Aliza Le Roux
University of The Free State – Qwaqwa Campus
At the end of a rather dry summer (Nov 2018-Feb 2019), we finally found the time to start playing with our new equipment – four new song meters! As we have extremely high winds in our mountains, I first wanted to test microphone gain settings before going to the wetland itself. For a few days, I therefore hid a song meter near our campus dam, and picked up a lovely array of warblers. To my surprise, I also picked up traffic noise from a fair distance away!
This try-out gave me the confidence to deploy our camera traps in the wetland itself.
A friend and I took an afternoon off and dug poles in the wetland using a soil corer and quite a bit of muscle power! Who knew how solid the clay-rich soil would be!
We put up our song meters in four likely-looking spots in the wetlands and let them roll for about 10 days, on a schedule of 20 minutes on, 40 minutes off, just to see how things might change over time. Sadly, I have not had a chance to look at these data at all, and we’ve been a bit afraid of putting up song meters in winter (fires regularly blast through the grassland).
But, the good news is that I’ve found some collaborators with expertise in Kaleidoscope, and they should be able to help me get over the learning curve when it comes to analysis. The best news is that these collaborators are in Japan. I see sushi in my near future!
Dr. Mark Hulme
University Of The West Indies, St. Augustine, Trinidad And Tobago
Since receiving the news of my Wildlife Acoustics Scientific Product Grant the Pawi project has been proceeding well. I now have an MSc student, Alisha Koulen, working on developing the methods to be used for the project and so far we have deployed Wildlife Acoustics SM4 recorders over 25 days at four different locations in the Northern Range of Trinidad know to have recent records of the Pawi (Trinidad Piping-guan). Three of these locations have resulted in positive detections, which is great news. The data for the fourth was retrieved recently and we are hopeful for more good news there. Analysis of the arrays of recorders at these locations and of planned playback experiments will help us to determine the detection distance for Pawi calls and wing drums in different forest habitats which will inform the survey design for next dry season, when the birds will start vocalising much more frequently than during the current wet season. We have started using Kaleidoscope software to automate the detection of Pawi calls and wing-drums, with some encouraging results. I will fine-tune this process and combine automation with manual identification. The sonograms for the piping calls and wing-drums are quite distinctive which makes our job a lot easier! The grant from Wildlife Acoustics, which has paid for the Kaleidoscope licenses, has added a vital element to the analysis and we hope the results will play an important role in the ongoing protection of this critically endangered species.
Georgia Southern University
During the first quarter of 2019, my Spring semester Field Biology class and I officially launched the SInGS (Singing Insects of Georgia Southern) project. During the initial phase, students learned basic GPS skills, how to describe habitats, and how to set up and install Song Meters. We identified five sites on the Statesboro campus that represented different habitat types (woodland, wetland, sand hill, disturbed, and urban; Fig. 1), and installed one Song Meter at each site on February 21 (Fig. 2). We set the meters to record five minutes every hour at a sample rate of 44,1000 Hz. We also set up a schedule to swap out the batteries and SD cards on a monthly basis (Fig. 3).
In the classroom, students learned the mechanisms and functions of sound production in animals, how to describe and analyze animal sounds, and how to use the Open Source audio analysis software Audacity to facilitate the location and characterization of insect calls. An earlier class surveyed the University of Florida’s “Singing Insects of North America” web site and constructed a list of 92 species of orthopterans (44 crickets and 48 katydids); this semester's class had the formidable task of characterizing the songs of each of these species (trills, ticks, chirps; peak frequencies, duration, complexity, variability, etc.) and assembling this information into a novel, spreadsheet-based identification aid. We engaged in a trial run of this Audacity-spreadsheet approach to audio identification by having the entire class attempt to identify two species of orthopterans in the same five-minute file. Based on the outcomes of this trial run, we tweaked the identification protocols as well as the guide itself. In late April students will each work through 24-25 files, identifying any singing insects they hear/see and identifying patterns of change over time (during a day, across the season) and differences among the five sites. During the April maintenance visit to each site, students will collect specimens using sweep nets, beater trays, and pitfall traps to compare and contrast with the audio surveys.
Luis E. Vargas-Castro
Foundation of the Distance State University for the Development and Promotion of Distance Education (FUNDEPREDI), Costa Rica
As one of the Scientific Product Grant Program recipients, 4th quarter of 2018, I am glad to share good news on how our citizen science project with high school kids is starting to develop. We have secured the participation of 5 local high schools (only one more pending!), in rural communities of Santa Cruz, Guanacaste province, Costa Rica. After a series of meetings with the principals and school teachers, I must say that we are truly amazed and motivated by the warmth and emotion with which they welcomed us at the different institutions visited.
In each one of these sessions, we explained why bats are key contributors to healthy ecosystems and presented the general plan of the research project. In addition, we described how innovative technological tools, such as the Echo Meter Touch 2s —kindly provided by Wildlife Acoustics— are useful to monitor wildlife. In this particular case, how students are going to be able to record bat ultrasounds just by conveniently connecting them to cellphones! I feel optimistic with the keen interest among our growing group of allies (from public and private sectors) in facilitating the students’ engagement with our project.
We have already set specific dates and coordinated most of the logistics for the upcoming workshops with the students, to teach them how to use the Echo Meter Touch 2s. Once they have received training and the equipment, we will start recording bats in a synchronized effort on multiple spots of the Santa Cruz landscape. Therefore, not only our research team will grow with their participation, but students will also benefit from experiencing science and technology first-hand. More importantly, project participants will then have the power to teach other people about the importance of protecting bats and the numerous benefits they provide. More soon!
Fairfax County Park Authority, Huntley Meadows Park, Virginia
Wetland losses have accelerated in the past 20 years resulting in significant habitat loss for obligate wetland species. Many marsh bird populations are declining as a result of wetland degradation and loss of wetland habitat. During the 1980’s and early 1990’s, the 50 acre Central Wetland at Huntley Meadows Park, in Fairfax County, Virginia, gained national notoriety for breeding marsh birds including rails, grebes and bitterns. Suburban development and stormwater pollution resulted in the degradation of the Central Wetland and the marsh birds stopped breeding in 1994. In 2014, the Central Wetland at Huntley Meadows Park underwent a large scale restoration project. The restoration project goals were to restore wetland ecosystem function, increase biodiversity and install control gates to allow staff to manage the wetland water levels.
David Lawlor is the Natural Resource Manager responsible for managing the wetland. Mr. Lawlor can influence vegetative communities and wildlife habitat by adjusting water levels. Water level management plans are created for each year and staff attempt to provide the best quality habitat possible for a list of target species. Marsh birds including American bitterns (Botaurus lentiginosus) , least bitterns (Ixobrychus exilis), Virginia rails (Rallus limicola), king rails (Rallus elegans) and pied-billed grebe (Podilymbus podiceps) are on the list of target species used to guide management decisions. These marsh birds have been seen and heard with more regularity since the restoration project completed and king rails bred in the wetland in 2016 for the first time in almost 20 years.
Mr. Lawlor and his team will use the Wildlife Acoustics SM4 recorders to monitor the Central Wetland for breeding calls of these secretive marsh birds to track their temporal use of the wetland. Mr. Lawlor intends to correlate the timing and frequency of marsh bird use of the Central Wetland with water level management practices. The information will be instrumental in guiding water level management plans in the future to provide optimal marsh bird habitat in the Central Wetland.
After identifying quality nesting habitat, the Huntley Meadows team set up Wildlife Acoustics SM4 recorders in the Central Wetland Park on March 27th in anticipation of the marsh bird’s arrival in early April. The data will be analyzed using Wildlife Acoustics Kaleidoscope Pro software with acoustic Cluster Analysis. Logarithms will be created using Kaleidoscope Pro software for breeding calls of each species. The species data will be analyzed for frequency of calls, temporal duration of stay and estimated location to help guide future water level management plans.
Manchester Metropolitan University (MMU) in the United Kingdom has been helping students for over twenty years gain practical experience before entering the workforce. Dr. Huw Lloyd, Senior Lecturer in Wildlife Ecology at MMU, conducts a 6-day field course, including one at the Caer Llan Field Centre in Monmouthshire, South Wales, for first year undergraduates (~19-21 years of age) on designing and conducting a field research project, which now includes bioacoustics. “Students get to work in small groups, learning new field skills and data analysis,” Dr. Lloyd explains. He continues, “In recent years, we have specialized in teaching key ecology employability skills to our first-year undergraduate students in not only species identification, traditional ecological field skills, and in the use of analytical software such as R, but also in the use of remote sensing techniques – particularly with the use of camera traps. Fortunately, in the last two years, we have been able to widen this approach and include bioacoustic monitoring.”
Originally, Dr. Lloyd and staff at MMU taught approximately fifty students at the Center, but now MMU runs two concurrent field courses for 150 student. Dr. Lloyd explains, “Students are faced with a number of challenges – scientific sampling design, data analyses, species identification, and the use of scientific literature. They are asked to conduct a field research project comparing the flora or fauna in two different woodland areas. Within the habitats, one being a protected area, students focus on one of several key taxa that they find interesting: birds, small terrestrial mammals, terrestrial woodland invertebrates, bats, etc.” He continues, “Students love working in a field environment, experiencing wildlife ‘close-up’ while using the latest remote sensing equipment. They work in small research groups with expert staff and get to know and bond with other students. For projects on bats, the SM4BAT FS and Kaleidoscope Pro enable them to learn and experience bats in a brand-new way.” The response from students has been positive. Dr. Lloyd reports “Student satisfaction with the field course and its other unit activities is currently high (>90%). Students who work on the bat project using the [SM4BAT FS] and Kaleidoscope software have produced excellent research project reports and verbal feedback has been extremely positive.”
Dr. Lloyd’s uses the SM4BAT FS and Kaleidoscope Pro software to teach bioacoustics; specifically monitoring woodland bat species. He recounts “During our field course in 2018, we managed to record 11 species of bats in just three nights of recording, including some species we have never recorded before (or did not realize were in the area), such [species] as Bechsteins, Greater Horseshoe and Barbastelle. The students loved these ‘discoveries’!” When asked about the challenge’s students face Dr. Lloyd explains, “Perhaps one of the greatest practical difficulties for students is learning about bat ecology and acoustic analyses in such a short space of time, but the utility of [Kaleidoscope] makes this possible.” He continues “This adds a new and significant student employability dimension to our field course (and other teaching activities). Combined with ground-based potential roost feature surveys, these technologies also offer us an opportunity to teach bat identification and ecology in a way that was not previously possible and help students develop skills relevant for ecological consultancy or academic research at a very early stage of their degree program.”
Dr. Lloyd has outlined how using Song Meters and Kaleidoscope software has made his class successful.
Learning to use real world equipment. Dr. Lloyd finds that students are enthusiastic about using Wildlife Acoustics equipment. They are excited when “…as researchers and lecturers we are able to show trust in them to use and service the recorders, manage the recordings and analyze the sound data”. However, students are not just handed recorders. Dr. Lloyd engages students in a small number of practice sessions in setting up the equipment and using the software. He finds “The Wildlife Acoustics tutorial videos (from the Wildlife Acoustics website) on Kaleidoscope are extremely beneficial in helping to teach sound analyses.”
A “non-traditional” approach to bat acoustics. Dr. Lloyd uses Kaleidoscope software to slow the recordings to a 1/8 speed. He speculates that this is “making the sounds a little more ‘tangible’ for our first-year students. So, we use, what I call an ‘ornithological approach’ to bat acoustics.”
Low Cost. Wildlife Acoustics offers free 15-day trials on Kaleidoscope Pro software. Dr. Lloyd recounts, “2018 was the first year we used Kaleidoscope Pro on our Caer Llan Field Course, and we only trialed the free 15-day version…this proved a great success amongst the students and now we have purchased annual licenses to continue using Kaleidoscope Pro for future years.”
MMU is now expanding the program to provide opportunities to train additional students in bioacoustic monitoring at other field centers using the SM4BAT FS.
Dr. Lloyd reports “We are currently expanding our first-year field course, as part of our new undergraduate Biology program. So we will be running an additional field course to Preston Montford, Shropshire, UK alongside our Caer Llan field course, for the foreseeable future. MMU has just purchased the first two annual [Kaleidoscope Pro] licenses and we will be using these and new SM4BAT FS recorders on some of our combined undergraduate/post-graduate field courses, such as the Tropical Ecology Field Course, at the Timburi Cocha Field Station, in the Amazonian basin in Ecuador.”
University of Ruhana, Department of Agricultural Biology
I received two SM4BAT recorders with two SMM-U2 Ultrasonic Microphones and an Echo Meter Touch 2 Pro in early October 2018. First, I tested each of the recorders overnight in fragmented forest patch at faculty of Agriculture, University of Ruhuna, Kamburupitiya, and further tested for different recording schedules. I have trained my research assistants, Mathisha Karunarathna and Chamara Amarasinghe, regarding every steps before install (includes opening recorder, insert batteries, insert memory cards, connect microphone cable, adjust different settings) and mounting recorders and microphones in the field. And also, we were learnt about how create recording schedules and what is the recording schedule of present study. Data analyzing part hasn’t been started yet. Test recordings were made using non rechargeable batteries and low capacity memory cards available with us. Rechargeable batteries, a battery charger and high capacity memory cards will be purchased in January 2019 from additional funds. Echo meter touch 2 pro was tested using Android operated smart phones by the team during same field testing sessions.
We are in a process to extend our permissions to conduct field works in all selected tea plantations from plantation managers and land owners and applied for extend our bat capture permit from Department of Wildlife Conservation, Sri Lanka. We hope to start out first field works on early February 2019 in 14 tea plantations representing all tea growing agro-ecological zones in Sri Lanka. Most of tea growing areas in the country have been affected by heavy rain falls and landslides during last few months. Weather in the country is presently becoming normal and hopefully we will gather very useful data regarding bat diversity and activity patterns soon.
We have started field work in mid February 2019 and field works conducted in seven sampling sites including Ginigathhena, Pundaluoya, Nuwara Eliya, Knuckles, Udapussellawa, Idulgashinna and Morawaka up to now. We have identified suitable recording sites using Echo meter touch 2 pro and two Songmeter SM4Bat FS detectors fitted with SMM-U2 ultrasonic microphones were mounted on shade trees inside tea plantations with positioning one bat detector at the edge of tea plantation and other one at the middle of tea plantation. Bat sounds were recorded in three consecutive nights in each site from sunset to sunrise to cover full nocturnal activity of bats. Assuming the night length to be 11 hours on an average, we collected roughly 231 hours of acoustic data. During the field works, our field assistants Chamara Amarasinghe, Mathisha Karunarathna and Sameera Suranjan were trained well about bat research. Now, they are well-trained not only in setting up bat detectors but also in identifying different genera of bats from recordings.
We have started analysing the recordings at University of Ruhuna using Kaleidoscope Pro software. Initial analysis suggests that we have recorded about 08 species of bats across different tea growing regions. Many feeding buzzes in the sound collection are indicating the promising use of tea plantations for bat foraging. Another interesting thing is different social calls of different bat species recorded during this sampling session. I hope that, we can learn a lot from these bat sound recordings about the secret lives of bats in tea plantations of Sri Lanka.
Wind power, the transformation of energy from moving air into electrical power, is a major step forward in reducing the effects of carbon emissions from the use of fossil fuels. Although the long-term benefits of harnessing wind power are great, there are some environmental costs that are inevitable including bat fatality.
Birmingham and Black Country Bat Group
Following the receipt of eight EchoMeter Touch 2 Pro bat detectors from the Wildlife Acoustics Scientific Product Grant in September, I have been working with volunteers to develop new methodology for surveying the use of linear features (canals and railways) by bats, looking for evidence of which bat species are using which types of feature to commute from their day roosts to their feeding grounds, and identifying important 'hop on' and 'hop off' points.
I designed the survey to utilise these detectors because they are full-spectrum, have an auto-ID feature, are user-friendly and would enable us to have GPS-tagged and time-stamped data. The idea was to spread out teams of recorders along a linear feature and (using both sound analysis and field observations) 'follow' the movement of individual bats as they passed each survey team.
The surveys have not been without their problems, and we have had to undergo a good deal of trouble-shooting, but I'm now delighted to say that the kinks are ironed out and we're gathering some useful data. Initially, we had some discrepancies between auto time-stamps between the phones people were using, as the difference in time between any two phones could be out by up to 5 or 6 seconds. This was enough of a discrepancy to skew my data, and we had to find a workaround: I purchased four Lenovo Tab 7 Essential tablets to use with the detectors, and I manually calibrate them prior to the survey to within 0.5 seconds of the atomic clock. This works a treat and I will be purchasing more tablets for the remaining detectors soon.
But having accurate GPS and time-stamps on my sound files was useless unless I knew how long it would take for a bat to fly between survey points. Published results on bat flight speeds vary greatly between species and geographical area. The Bats and The Millennium project in Scotland measured the speed of Daubenton's bats along canals as having an average speed of 5.3 metres per second (MPS). Was this a good analog for my bats along this particular stretch of canal? I had no fancy equipment like lasers or radio tags to find out, so I decided to test it out in a rather old-school way…
I positioned 6 surveyors at 20m intervals along a straight stretch of canal, covering exactly 200m. Using EMTouch2Pro detectors, red LED torches, stopwatches and walkie talkies, we timed Daubenton's bats to ascertain their speed (4.9 mps, which was pleasingly close to the BATM study figures).
Using that speed, I was able to figure out how long it should take each bat to travel from each point along the canal to the next survey point, and as such I could look for a corresponding Auto-identified call in the next team's Kaleidoscope report.
…and it works. The green cells you can see in the spreadsheet above represent calls of a Daubenton's bat as it passed survey points Golf, Foxtrot and Echo – heading north (as anticipated) at almost exactly 4.9mps.
I really feel as though we have our equipment and methodology sorted out and hope to roll out this survey method as soon as bats wake up from hibernation in April! I've even got something in the pipeline to develop an R-script to automatically search for my correlated species calls from different survey points. Something to work on for the winter months…
Dr. Kimberly Andrews
University of Georgia, Odum School of Ecology
We are in Q1 of our project investigating the vocalization of gopher tortoises (Gopherus polyphemus), so we have not yet received results from our study although we maintain confidence in our ability to succeed at our proposed goals. The occurrence of tortoise vocalizations simply has been documented but not characterized; hence, we are delving into when and under what circumstances these vocalizations occur. We are currently launching and testing our methodologies and exercising an adaptive approach to our study design accordingly. We initially deployed the Wildlife Acoustics units in a captive setting with young (~1 yr) gopher tortoises as a pilot setting. Following those tests, we then deployed the units in the field at a Georgia Department of Natural Resources Wildlife Management Area with the project goal of monitoring communication in wild populations. Specifically, we are interested in whether animals who were relocated from a mining site are interacting with resident males. This project uses Wildlife Acoustic units as a novel means of validation and is being used in concert with wildlife camera data. As directed by these two technological methods, we will collect genetic samples from hatchlings that are produced from nests where we heard and observed male-female interactions using the cameras and acoustic units.
The exploration into low-frequency (Less than 5 kHz) vocalizations in turtles and tortoises is a new frontier. These research endeavors add uniquely to our understanding of these animals' natural history. Further, this technology from Wildlife Acoustics allows us to quantitively and qualitatively study interactions in a manner that is biologically meaningful to the tortoises. By describing meaningful interactions among individuals, we can better interpret intra-populational interactions as indicators of true population health.
This work is conducted by the Andrews Applied Wildlife Conservation Lab (AWCL) at the UGA Odum School of Ecology. We operate out of a partner facility, the Marine Extension in Brunswick, GA. This Wildlife Acoustics project is a partnership with Southern Ionics Minerals, who executes a strong stewardship and wildlife conservation mission of translocating tortoises to lands where they can receive long-term protection. These recipient sites are managed by the Georgia Department of Natural Resources, who additionally engage in establishing our research priorities and providing our scientific collection permits that are necessary to conduct the work.
Our findings will absolutely influence existing conservation priorities and policy. We will use these data as a key method in an integrated approach to assess whether translocated and resident tortoise individuals are interacting and reproducing. If so, we can confirm that our mitigation and management efforts to translate tortoises are effective in meeting our goal of augmenting the sizes of resident populations on state lands. If population sizes meet those of the Minimum Viable Population classification set by the US Fish & Wildlife Service, these populations will count toward our goal of the species receiving a secure, rather than a threatened or endangered status, in the current petition review of the species for the Endangered Species Act.
As part of our research in the UGA Applied Wildlife Conservation Lab, we are continuing to monitor the activities of adult gopher tortoises with our SM4 recorders received from Wildlife Acoustics. These units are placed at the burrows of female gopher tortoises, some of which have been relocated from a heavy mineral mining site. We are interested in whether these newly established females are interacting with the resident males. Our monitoring process is adaptive as the level of tortoise activity varies in space and time and among individuals. As these radio-tracked individuals move among burrows, UGA researcher, Oscar Thompson, moves the recorders accordingly to "follow" these females. By determining which females have the highest number of male interactions, we increase our probability of capturing vocalizations between the sexes. We set the game cameras to look directly at the burrow to capture any social interactions that occur in front of the burrow, and then place our SM4 recorders to the side, where they will not obstruct our cameras but still capture any vocalizations made during interactions. By coupling our acoustic output with game camera data collected at the same burrows, we can isolate which vocalizations are tortoise-talk by pairing them with the images of tortoise interactions.
As we are early on in our acoustic research, this past quarter involved "training" our Kaleidoscope software to recognize tortoise banter. Initially, each of our 5 SM4 recorders was recording approximately 45 hours of audio files a week for a total of about 220 hours of audio recordings to analyze every week. Since gopher tortoise vocalizations have not been characterized previously, we are on the frontier of identifying the frequency and behavior of their vocalizations! Exciting stuff! To begin streamlining our searches, we referenced the camera data where we could confirm an interaction between two individuals and homed in on the audio recording for that date and time segment to identify vocalizations between individuals. Based on that characterization and using the Kaleidoscope Cluster Analysis function, we have been able to identify several different individual calls, including those that occur during mating. Our next step is to differentiate whether the differences in calls are attributable to differences in types of activities or based on individual variation.
In addition to capturing gopher tortoise vocalizations, we have been able to record numerous species of birds, as well as several different species of frog in the areas around the burrow.
This past quarter, we have continued to collect and analyze our acoustics data, all the while refining the cluster analysis classifier to increase the accuracy in our data sets. Based on the frequencies and patterns of the gopher tortoise vocalizations that we are attempting to isolate, we experience a high rate of false positives where Kaleidoscope is classifying other sounds with similar characteristics as gopher tortoise vocalizations. To ensure the accuracy of our data sets and eliminate the false positives, we are still manually identifying all vocalizations that Kaleidoscope classifies as tortoises, using the photos collected from our game cameras that are trained on the apron of each burrow to verify interactions. In a typical week’s data during the active tortoise season, we record and identify about 800-900 gopher tortoise vocalizations from our five SM4 recorders.
Additionally, this past fall, we conducted a trapping session to recapture the telemetered tortoises for equipment replacement. This telemetry equipment is central to the operation of this study as we move the cameras and acoustic units among burrows based upon movements confirmed through the GPS and VHF telemetry. Finally, we sent genetics samples to Dr. Stephen Spear, the lead geneticist at The Wilds in Columbus, OH for analysis. These samples will confirm which individuals are reproducing. We then can compare those data against the animals that we have seen on cameras and heard on the acoustic units for a more comprehensive integration of the behavioral and reproductive ecology of these gopher tortoises.
With lower temperatures in the 2nd half of November, the gopher tortoises at our study site have greatly reduced their activity levels and are settling into their burrows for the winter. Hence, we are receiving very few interactions or vocalizations on the cameras and recorders. Due to this reduction in activity, we decided to suspend our acoustic sampling until spring while maintaining our effort on further analyzing the almost 1,800 hours of audio data that we have collected with our five SM4 recorders. We are continuing with our project of matching individual vocalizations to game camera photos so that we can classify different vocalizations with specific behaviors. To date, we have been able to classify three vocalizations with specific behaviors. In addition, we have identified approximately 8-10 other vocalizations from the audio data, but still need to determine whether they are associated with specific behaviors. We hope that we can create an even more accurate Kaleidoscope-Pro cluster analysis file to better classify our data next year and reduce the number of false positives that are classified as gopher tortoise vocalizations.
In October, UGA researcher and project co-PI, Oscar Thompson, presented a poster on the Wildlife Acoustics project. This presentation outlined our methodology for deployment and analysis along with some preliminary results at the 40th annual Gopher Tortoise Council meeting at Archbold Biological Station, in Venus, Florida. The poster was very well received, and many people are looking forward to our results and the potential application in their studies with the species. A pdf copy of this poster is being submitted with this report. We are also targeting a publication to submit in 2019 outlining our application and methods.
Dr. Emilia Grzędzicka
Foundation for Silesia Park
The project began on 1st May 2018, with the preparation of a voice bank of 18 insect species belonging to the Tettigonioidea group, that live in the research area (S-E Poland). Files found using the Internet were used to learn how to distinguish species by their voices in the field. Since mid-June, 10 locations with xerothermic grasslands in the Nida Valley have been visited. Those are the positions of protected grasshoppers, the heath bush-crickets Gampsocleis glabra, found in earlier studies by other authors. On every location with protected grasslands, 3-5 research plots – each of which has an area of 1000 m2 – were designated for recording concerts of singing grasshoppers and describing plant vegetation. The first adult heath bush-crickets were found in the last week of June. Until 30 June, 10 grasshoppers’ concerts were recorded using the digital recorder Song Meter SM4, which is 25% of concerts planned to be recorded in the first dates of the field inspection (which is until 10th July). In the next dates, it is planned to record at least another 100-110 concerts of insects for analyses in the Kaleidoscope program. The year 2018 is dry in Poland, and the air temperature is often very high (above 25°C, even above 30°C), which positively affects the voice activity of Tettigonioidea, which do not sing below 17°C. Both the large habitat diversity shown at research sites, as well as the favorable weather conditions have so far promoted the feasibility and success of the project.
Since the submission of the previous grant report, field studies planned under the project have been completed. The number of singing males of the heath bush-cricket Gampsocleis glabra found in 2018 in Poland can be estimated at around 100, which means that the population size is around 200 insects assuming that every singing male lured the female, or even less if we assume that males were more numerous than females. The average density calculated based on all controls was 1 specimen/ 1000 m2. These data clearly indicate that the population in Poland needs urgent and thoughtful conservation strategy.
In the case of steppe animals, the best way of their conservation is to describe accurately their habitat preferences and plan such treatments (e.g. mowing and grazing) at locations that would increase the area of the most optimal habitat, which was the main goal of the project. Habitat of G. glabra was described on small squares 1×1 m around singing males. On each square, one phytosociological relevé was taken, consisting in listing all plant species present there with the scale of coverage of each plant species per square. For comparison, squares without heath bush-crickets were also designated, where the habitat was described similarly, as the example not preferred by protected insects. Since the plant censuses were updated during every control date (20.VI-10.VII; 15.VII-10.VIII, 1-20.IX), phytosociological relevés provide a complete picture of the vegetation. A strong preference for the steppe xerothermic grasslands from the Festuco-Brometea class was demonstrated for the heath bush-cricket. A total of 112 plant species were listed on the example 28 sites with G. glabra and 25 relevés without it, from one location. 49 plant species were xerothermic ones, and 63 were typical meadow plant species from the Molinio-Arrhenatheretea class. On the sites occupied by the heath bush-crickets, on average 55.8% were xerothermic plants, which was significantly more than only 21.8% of xerothermic plants per 1m2 observed on squares without the researched insect (Mann-Whitney test: Z = -6.23, P >0.0001, df = 1). This means that the phenomenon of expansion of meadow plants in the area inhabited by the heath bush-cricket is unfavorable for this species.
It has been shown that G. glabra lived in places where the vegetation below 10 cm had an average vegetation coverage of 98.7%, and at a height of 40 cm only 35.4%. The value in the second case was significantly lower than the average 60% vegetation coverage in squares without the protected species (Mann-Whitney test: Z = 6.05, P >0.0001, df = 1). This result suggests the heath bush-crickets’ preferences for dense vegetation near the ground (potential shelter, for example from the sun) and rarer vegetation a bit higher, e.g. to find a well-exposed blade of grass useful for a good voice communication (dense plants suppress acoustics).
Xerothermic grasslands, which are the optimal habitat of the heath bush-cricket, should be mown in a mosaic of patches mowing alternatively in different years. The gradual grazing from June to September is not recommended for the safety of insects that could fall prey to animals. The project also allowed to suggest the date of mowing – preferably after 25th August. The last day when G. glabra was heard was 29th August 2018, and only 3 specimens were found in one location. Although the recordings of various Tettigonidae were made at the September dates, same as habitat description, heath bush-crickets were no longer heard in September, although it could have been the effect of an exceptionally warm year that speeded up the phenology in nature.
The results of the research carried out during the project were presented in the oral presentation of the author, at the II. International Orthopterological Symposium in Smolenice in Slovakia (September 19-21, 2018). The speech met with great interest and the results were discussed with specialists. The next stage of the project will be the in-depth analysis of collected recordings of insects' voices, and the preparation of an article.
The preliminary analysis of the heath bush-crickets’ sound recordings has shown the dependence of their voice activity on the temperature noted on each day of study. It turned out that as soon as the sun was hiding behind the clouds or the temperature dropped below 20°C, the voice activity of insects was reduced. The phase duration (PD) relationship with habitat quality was also shown for 4-5 min. recordings of G.glabra voices (after cutting out fragments, when voice activity decreased due to the weather conditions). The higher coverage of xerothermic plant species, the longer the PD (Spearman correlation coefficient: rS = 0.39, P = 0.036), so in more xerothermic habitat communication between insects was more effective.
In the third reporting stage of the project, a more detailed analysis was prepared using W4V sound files, which were recorded with the digital Song Meter SM4. First, the author listened to the recordings to know exactly where the unnecessary disturbances were recorded, e.g. wind, voices of people or cars. Only carefully selected 4-5 minutes fragments were analyzed. In the Kaleidoscope Pro 4.5.5 program, the following parameters of the heath bush-crickets’ voices were measured: intensity in dB: minimal, maximum, medium; frequency in kHz: min. (lowest frequency LF), max. (highest frequency HF), mean frequency (MF) and the average frequency of “peaks”, which was defined as a dominant frequency (DF).
Seven GLM models were designed in the JMP 8 statistical program on N = 80 voice files with Gampsocleis glabra recordings from different dates, taking into account “recording date” as a factor (as the habitat changes dynamically throughout the season); the other two explanatory variables were: the type of habitat (1 – meadow, 2 – xerothermic) and distance to the edge of the crop (1 – far; 2 – near). No significances in voice frequency-related GLMs have been found, which means that the type of habitat (and therefore its smaller or larger degradation of xerothermic grassland towards the meadow) did not affect the frequency of male voices. The average singing intensity also did not depend on habitat, but only on its edge: it was lower at the border of steppes with cultivation (-17.57 dB) than in the middle of habitat (7.03 dB). This can be explained by the lack of a competitor on the outskirts of inhabited patches. Max. volume of voice was determined by the type of habitat – higher in the meadow (1.24 dB) than in the xerothermic grassland (-0.29 dB).
The most interesting and surprising result obtained within the framework of the project is the lack of a clear link between the presence of the studied G.glabra with bunchgrasses Stipa spp., which presence largely qualifies the given habitat as a steppe. It turned out that the coverage of Stipa capillata was significantly higher in patches inhabited by the heath bush-crickets than in the others (Mann-Whitney test: Z = -3.25; P = 0.001), but on the other hand – Stipa sp. grew only in 36 % of the research areas inhabited by G.glabra. The key species of grass in sites of the examined insect was the tor grass Brachypodium pinnatum – typical for xerothermic grasslands from the Festuco-Brometea class, which grew in 93 % of patches inhabited by G.glabra and only in 16 % of the other examined areas. Plant communities with this grass resemble the physiognomy of the steppes with tall, rather dense stems, freely moving in the wind, denser closer to the ground than above.
Furthermore, a negative correlation was found between the number of G.glabra vocal episodes per recording and the mean coverage of B.pinnatum in the patch (Spearman correlation: rs = -0.57, P = 0.002, N = 53), as well as a significant positive relationship between the total length of male singing in the recording (phase duration, PD) and the coverage of the tor grass (Spearman correlation: rs = 0.57, P = 0.001, N = 53), which suggests a large energy expenditure for singing in habitat dominated by B.pinnatum. This may result from the presence of competitors from the same species in xerothermic habitat with a high abundance of tor grass, which stimulates males to intensify their singing.
Recorded and listened concerts of the heath bush-crickets with males of other species belonging to the Tettigoniidae family in the background did not show interspecies competition in singing. It has not been found that G.glabra males were regularly interrupted when other species were singing. Other species of grasshoppers shown in the vicinity of the heath bush-crickets were mainly: Roesel’s bush-cricket Metrioptera roeselii, Metrioptera bicolor, dark bush-cricket Pholidoptera griseoaptera, wart-biter Decticus verrucivorus, Tettigonia caudata. Some of them do not have such habitat specialization as G.glabra for xerothermic grasslands; for example: M.roeselii with a very similar voice is a species typical for dry meadows but with small habitat requirements, D.verrucivorus prefers low vegetation and P.griseoaptera prefers meadows overgrown with shrubs – in contrast to the tested protected insect. There may be no voice competition between species, because they separate in space while living in other habitats. The only exception is M.roeselii, who occupied habitat patches similar to those in which G.glabra lives, in locations without the second species. The progressive degradation of xerothermic grasslands may, therefore, decline the heath bush-cricket through the expansion of less demanding habitat grasshoppers, but not through the voice competition between them. Since there was no regular voice competition between different species within the project, it can be concluded that disappearance of vegetation with the physiognomy of high grassland steppes and strict specialization of G.glabra contribute to the decline of this species in Poland.
The results of the project were discussed in detail during seminar at the Institute of Systematics and Evolution of Animals of the Polish Academy of Sciences in Krakow on December 11, 2018.
Steppes and xerothermic grasslands are hotspots of biodiversity, but they are among the most endangered habitats in the world. The main threats are habitat degradation and fragmentation. Non-mobile species, and at the same time those inhabiting patches isolated from a compact range, are most vulnerable to extinction. An example is the heath bush-cricket Gampsocleis glabra. It figures in several European national Red Lists as an endangered species. In Poland, it reaches the northern edge of its range, and Polish population is also isolated from a compact range. Research carried out during the project showed that sites chosen by the heath bush-crickets differed significantly from the unoccupied ones. It turned out that even on a patch in Poland, isolated from a compact range for many years, G. glabra still maintained clearly defined preferences for steppes and xerothermic grasslands from the Festuco-Brometea class, which affects its acoustic communication and survival. Detailed studies of habitat preferences and bioacoustics of endangered populations on isolated locations – like this project – should be a prelude to the restoration of similar locations in Poland and the whole Europe that have disappeared and to the development of a global strategy to protect the described species. The results obtained under the project will be published in two international articles, and the first has already been written and sent to the journal in March 2019.
Author of the project kindly thanks Wildlife Acoustics for the support that allowed to carry out the research, which will help to protect the beautifully singing insect threatened with extinction.
Diego Llusia, Manuel B. Morales & Juan Traba
Universidad Autónoma de Madrid
Spring is arriving at northern Spain and the research activities of our Wildlife Acoustics Scientific Product Grant have already begun. Let's get started on searching for the ghost of the moor and habitat corridors for its conservation. The Dupont's Lark (Chersophilus duponti), a highly cryptic bird, is endemic of Mediterranean steppe habitats and currently one of the most endangered passerines in Europe. Mainly due to habitat loss, its distribution range is now strongly fragmented. To assist in conservation actions, the first stage of our project was devoted to identify potential corridors for the Dupont's Lark that can serve as bridges connecting isolated populations. These corridors have been defined based on available environmental data sets and well-established scientific knowledge about species' habitat selection, behavior and population dynamics. Then, the Wildlife Acoustics SM4 took action. Using the three automated recorders kindly granted by Wildlife Acoustics, pilot acoustic surveys have recently been conducted in several locations of the study area with known presence of the species in order to test diverse audio settings (gain, sample rate, etc.) and recording schedules. Deployed in hidden spots on Dupont's Lark habitats, these devices carried out continuous recordings during the first hours before sunrise. Thereby, we can establish optimal sampling protocols for future acoustic surveys, ensuring best detection probabilities. The next step of the project, now when spring starts, will be to confirm whether the ghost of the moor uses these potential corridors, where the species is usually extremely difficult to detect.
When nights are still cold and long, nocturnal choruses of the Dupont's Lark (Chersophilus duponti) begin to be heard in moors of the Iberian Peninsula. Males of this cryptic passerine exhibit their acoustic displays one or two hours before sunrise, by producing a metallic and high-pitched song while flying around their territories. Taking advantages of this phenomenon, Wildlife Acoustics SM4 were installed at potential corridors for the species during the last three months. These corridors were identified in a previous phase of the study. The large autonomy and programmable recording schemes of the SM4 enabled us to obtain 2-hours continuous recordings at dawn throughout the breeding season. Using this technology, we were also able to conduct the acoustic surveys at several sites simultaneously, while the efficient camouflage of these devices prevented changes on the behavior of the study species. Doing so, we aimed at recording the singing activity of the ghost of the moor and confirming whether it uses these corridors during mating and dispersal, which can be crucial information for the conservation plans of this endangered species. Sound files corresponding to hundreds of hours of environmental soundscapes were created during this sampling period. Next efforts will be focused on detecting the presence of the species in such a large acoustic data set.
Photo credits: Adrián Barrero
Globally, the growth rate of suburbanization is greater than the human population growth rate, and suburban cover now exceeds 25% of land in most developed countries. Suburban sprawl, essentially landscape conversion, is a major issue effecting biodiversity loss. Amphibians are known to be the most rapidly declining taxa and landscape conversion is recognized as a driving factor in this decline. However, wood frogs (Rana sylvatica) have been studied as a suburban -tolerant species. In fact, they can be found breeding in ponds surrounded by over 70% suburban cover.
Ask any biologist about their fieldwork and war stories of nature's fury will surely arise. The Kaua'i Endangered Seabird Recovery Project have their own stories to tell. The pictures may look idyllic, but the terrain they work in is extremely challenging. Dense vegetation, steep ridges and deep drainages make up their research areas. In addition to this, heavy rain and dense fog is a constant struggle. The project's main focus is the conservation of three endangered seabirds; Newell's Shearwater Puffinus newelli, Hawaiian Petrel Pterodroma sandwichensis and the Band-rumped Storm-petrel Oceanodroma castro on the island of Kaua'i, Hawai'i.
A joint project of the Hawai'i Department of Land and Natural Resources (Division of Forestry and Wildlife) and the Pacific Co-operative Studies Unit of the University of Hawai'i, Kaua'i Endangered Seabird Recovery Project's (KESRP) main aims are to monitor island-wide population trends, undertake monitoring in remote colonies and conduct research on the threats facing these endangered birds (particularly related to power line collisions, light attraction and introduced predators). With information in hand, they work with land managers, the State of Hawai'i, US Fish and Wildlife Service and private entities to figure out the best ways to protect the endangered seabirds from these threats.
Acoustics plays a major role in understanding threats facing seabirds. Field testing determined that acoustic monitoring is one of the most effective ways to answer many conservation questions. This is because all three of the seabird species are a) only active at night, b) nest in underground burrows, and c) largely restricted to rugged montane habitat on the island- making traditional surveys very challenging.
Wildlife Acoustics Song Meters were deployed to help answer questions about the extent of powerline collision impacts to the long-term survival of Newell's Shearwater and Hawaiian Petrel and the effectiveness of predator control management strategies being under taken within key seabird colonies. In addition to this, acoustics is being used as an exploratory tool to locate new colonies of all three species in remote mountains of Kaua'i. "We started out using SM2+ and have something like 200 of them - quite a big operation." says Dr. Andre Raine, project coordinator. After trying SM3s the team settled on Wildlife Acoustics SM4. "The SM4, that was a huge step forward - more reliable, better battery power, better microphones." As the stock of SM2s that the project owns become older and eventually cease functioning Dr. Raine will continue moving forward with the SM4s, "We have done some side-by-side comparisons with our SM2 units to make sure there aren't significant differences in how many seabirds calls the SM4s record, as otherwise we would need a correction factor for our year on year comparisons. Seeing as there aren't differences we are happy to replace our SM2s with SM4s in the future."
The Kaua'i Endangered Seabird Recovery project isn't the only community interested in understanding more about powerline collisions. The Kaua'i Island Utility Company is eager to understand seabird powerline strikes and understand how best to reduce their take of endangered seabirds. Song Meters were placed under powerlines across the island of Kaua'i. "Although this may sound like an odd application, the fact is that these endangered seabirds make a unique noise when they hit power transmission lines when they collide with them at night!" says Dr. Raine. The unfortunate reality of understanding powerline collisions is that there are 100s of kilometers of powerlines on Kauai and so documenting them can be expensive, logistically challenging and would require large numbers of human observers operating all night throughout the year. Dr. Raine goes on to explain "The automated Song Meters and analysis have allowed us to increase the spatial and temporal survey effort across the island tolling survey efforts of 250,000 hours over the last 5 years... This would not be possible with human observers unless very large levels of funding and people were available. As the units are standardized it also prevents any issues one might have with observer bias."
For colony monitoring Song Meters are stationed for three months at a time at static locations within each colony. For exploratory work, Song Meters are even deployed from helicopters using grappling hooks! Specially designed deployment boxes were invented to deploy and retrieve Song Meters over terrain too difficult for observers to get to. Dr. Raine found that this method of helicopter deployment and retrieval was highly effective in these types of areas. However, he cautions "this is a complex and challenging method that needs to be considered carefully before being used."
Annually the Kaua'i Endangered Seabird Recovery Project deploys about 200 Song Meters. For them, environmental conditions are the most challenging aspect of using Song Meters. The terrain is difficult to work in and extremely wet. In fact, Kauai is the eighth wettest place on earth. Earlier in the project, this led to challenges of data loss due to saturated microphones. Dr. Raine, however, found that they could significantly reduce data loss by adding rain shields and spraying the microphones lightly with Scotch Guard.
Through the use of Song Meters, the Kaua'i Endangered Seabird Recovery Project, with help from Conservation Metrics Inc. (who analyze all the data), has generated models that highlight the extent of powerline collisions on Newell's Shearwater and Hawaiian Petrels, and also pinpoint key collision hotspots to be targeted for minimization actions. They have also been able to monitor the change in call rates over a seven-year period at key colonies to estimate the effectiveness of predator control efforts. Lastly, Song Meters have been key in locating new unknown colonies of all three endangered seabird species.
Funders for the Kauai Endangered Seabird Recovery Project include: State Wildlife Grants, funds from the Kaua'i Island Utility Co-operative Habitat Conservation Plan and the National Fish & Wildlife Foundation.
Photography Credit: Dr. Andre Raine
Thanks to Dr. Andre Raine from the Kaua'i Endangered Seabird Recovery Project team who provided most of the content for this case study.
Kasey Cope and Slaney Stringer
El Dorado High School Natural Resources Program
Receiving this grant has definitely been the highlight, as well as the turning point of our senior project. We had no idea how easy it would be to collect so much data in such a short period of time; it has made every aspect of our population more successful.
The Song Meter SM4 has worked amazingly well; it was extremely easy to program the recorder to record for 30 minutes off and on every day. This fixed one of our main issues, which was not being able to survey bird life at sunrise and sunset, when most of the birds are out. Now the data we have collected from one of our forests, a sugar pine grove, is much more consistent, unbiased, broad, and accurate. We mounted the Song Meter approximately 11 feet above the ground in the middle of the forest after programming it, and left it out for several weeks. After plugging the SD cards into our computer, we were able to see the all of the files with bird audio data. Since then, we have undergone a few struggles using the software. We had difficulty figuring out what all of the numbers in the data sheets meant, how to read the frequency distributions, and how to lower the sound contrast so that it is easier to hear the bird sounds. However, we learned how to do all of these things by talking to Chris from Wildlife Acoustics customer support. He was extremely helpful and now we have no problem listening to the audio files, identifying them with the help of the Song Sleuth mobile app, and sorting similar files into clusters. At the end of this year our data will be very substantial for our campus so that future students that take on this project have a strong foundation to build off of.
One thing that we had the privilege of doing in January is visiting a class of 7th graders to discuss our project and things we have learned. We gave a presentation about the importance of biodiversity, as well as explained the concept of our population study. We then had the kids participate in a scavenger hunt to identify birds at different stations that had pictures, recordings, and feathers. They learned how scientists can identify and record information about wildlife using field guides, data sheets, and audio recorders, like the one we have. It was very rewarding for us to see how much fun they had because of the knowledge we have gained over the past several months.
Finally, we have another event coming up that is an opportunity for us to further share this knowledge. On April 13th, our Natural Resources program hosts Natural Connections Day; this is when many classes from middle schools in our area come to our campus for a day and learn about various topics related to Natural Resources.
Devon Wildlife Trust
Since the grant was awarded we have been busy using our SM4 detectors and the new microphones. They have been out as part of two citizen science winter research surveys – why leave the detectors idle all winter?! – looking at landscape usage by greater horseshoe bats in the colder months. We are just starting to analyze the results and have picked up lots of recordings. Unfortunately we have lost some as the batteries are losing voltage in the really cold weather – but we hope to be able to report on the findings over coming months.
The project team are just gearing up to the start of our main citizen science programme – the Devon Bat Survey! The idea behind this is that anyone can take part by borrowing a bat detector from one of our 20 monitoring centres and surveying a chosen 1km grid square. Bookings opened two weeks ago and over a third of the 991 slots are already booked for this summer! The detectors and all the kit are in the process of being taken out to the monitoring centres, ready for the first sessions to start on March 29th. We are looking forward to getting the first sound files back for analysis and seeing if we can add to our knowledge of where Devon's bats are!
With only five weeks to go until the end of the 2018 Devon Bat Survey, we have received 622 SD cards back from participants, processed 650,000 sound files to look for bats and sent out 528 reports! We have two dedicated volunteers who are helping with the survey, one of which has already verified 1,327 greater horseshoe bat passes. We have uncovered new hotspots of activity in the county and will use these to focus our research work in 2019. We aim to have updated hotspot maps for greater horseshoes on our website by the end of 2018.
Our winter research surveys revealed some interesting behaviour. Greater horseshoes were recorded 1.15km away from their known hibernation roost, and the average temperature on the night with the highest activity (31 passes) was just 30C. This has led to more questions and we hope to be able to extend the survey this winter via a passive surveillance method of selecting twenty sites around the roost and leaving the detectors in situ for three months. Results of this will be available by mid-2019.
We're now two months into the 2018 Devon Bat Survey and 658 people have requested a square to survey – an amazing two-thirds of available booking slots! The project team has been busy supporting the 20 Monitoring Centres (see map with this report), dealing with any queries from surveyors and processing the returned data cards. A volunteer assists in downloading the data and returning the SD cards to the centres to ensure the smooth running of the survey. Tweaks and updates to last year's survey have helped to improve the efficiency and running of the survey.
Feedback from surveyors is very positive overall – they find that the instructions are clear and the equipment is easy to use. We have started to send out reports to those who have taken part – most people are amazed at the variety of bat species using the countryside near their homes – up to 10 or 12 species in some cases. Data from the winter surveys will be collated and analyzed; this all takes time as records needs verifying. Overall, this is a popular project that people all across the county are keen to get involved in.
The Devon Bat Survey’s 2018 season ended on November 2nd, with 728 people having taken part and returned sound recordings. This generated just shy of a million sound files! The team are still in the process of verifying the number of bat passes, but initial analysis shows that there is likely to be in excess of 500,000 confirmed passes. This year we recorded 3,376 greater horseshoe passes at 270 locations – a much higher figure than in 2017. This included two new hotspots that the project was previously unaware of, and these will be investigated further in 2019 with targeted surveys. Results from 2018 can now be found on our website.
All the data for non-horseshoe bat species is currently being manually checked by our project volunteers to confirm the species identification assigned by our automated classifier. Volunteers have also received training on sonogram analysis, starting with AnalookW software and progressing to Kaleidoscope. Once checked the records are sent to the Devon Biodiversity Records Centre where they are available for use to inform conservation priorities in the county. The greater horseshoe records are already contributing to a new Supplementary Planning Document for one area of Devon, providing additional protection to populations at risk from housing developments.
All greater horseshoe records are helping the project to focus its land management advisory work. It allows us to link up areas of known greater horseshoe use, providing the bats with additional routes through the countryside, potentially opening up new feeding grounds to them. It is also opening up investigatory routes to look for new roosts. Some of the records from 2018 will now be cross- referenced to the database of existing roost location records. Where no roosts are currently known in the locality, we will focus recording efforts in 2019 and 2020 to try to establish where these bats are living.
The winter 2017/18 detector survey provoked some interesting questions about landscape usage during what is normally assumed to be a hibernation period for greater horseshoe bats (Braunton report attached). Because of this, a second winter survey has been set up to attempt to answer further questions in 2018/19. Twenty SM4 detectors have recently been placed in static locations within the countryside around a known hibernation roost (including a detector at the roost exit). The detectors will record for at least three months during the main winter period, and all activity will be compared to weather data and habitat type. Any significant findings will help to tailor our land management advice around hibernation roosts and will be disseminated to project partners and the wider public.
Rohit Chakravarty and Dr. Anand Krishnan
Indian Institute of Science Education and Research-Pune
We received our SM4BAT recorders and an Echo Meter Touch 2 Pro in early February, and have been hard at work getting them tested and recording bats in Pune, prior to fieldwork in the Himalayas. First, we tested each of the recorders overnight on the IISER Pune Campus, and recorded a great deal of bat activity as the weather warms up! We have trained a student volunteer, Ram Mohan, in the use of these bat detectors and in basic analytical tools, and he will play a major part in this season's fieldwork. To get our educational and outreach activities started, we also conducted a bat walk on campus using the Echo Meter Touch 2 Pro. During both these activities, we identified and recorded calls of at least five bat species, including the Indian pipistrelle (Pipistrellus coromandra), the greater yellow house-bat (Scotophilus heathii) and the Egyptian free-tailed bat (Tadarida aegyptiaca).
All the other equipment for fieldwork has also been procured, and RC has now left for the Himalayas in Uttarakhand to begin our first field season. This work will last until mid-June at least, and will involve both our student volunteer and two field assistants (both of whom will also be trained in the use of recorders). Fieldwork from now on will focus on identifying suitable recording sites at four different elevations and getting acoustic data. Bat activity is likely to pick up by late March, so hopefully we will gather useful data on distributions and activity patterns soon!
In mid-March we were into the most anticipated leg of our project: field work! We reached Kedarnath Wildlife Sanctuary on 13 March and conducted fieldwork up till 15 May. After nine days of reconnaissance, we had finalised our recording sites. In order to have coverage of various habitat types and species, we placed our recorders in three habitat types: forest, forest edge and open areas. Our sampling locations also covered an elevational gradient from 1400 to 3700 m above sea level. Depending on the area of the sampling location and the habitat heterogeneity at various elevations, we had up to three spatial replicates of each habitat type. A breakdown of our recording sites is given in the following table. We recorded for two consecutive nights at each recording site. Assuming the night length to be 10 hours on an average, we collected roughly 760 hours of acoustic data!
During the course of fieldwork, we trained our field assistants Zareef Khan Lodha and Baseer Baniya Gujjar. Zareef and Baseer are from a small village in Uttarakhand and have been assisting biologists for the last five years. We have trained them in all aspects of bat research, and they are now well-trained not only in setting up bat detectors but also in identifying different genera of bats from recordings!
We are now back at IISER Pune and we have started analysing the recordings. Our intern, Ram Mohan is playing an important role in this step. Preliminary checks suggest that we have recorded about 15 species of bats across the elevational gradient, including the highest elevation record of the European Free-tailed Bat (Tadarida teniotis). We also have possibly the first recordings of social calls of bats from the Himalayas. We cannot wait to unravel more exciting distribution and activity patterns!
Dr. Michael Schöner
University of Costa Rica
The aim of our project, effectiveness of artificial roosts for Neotropical bat species is to efficiently attract especially vulnerable bat species to artificial roosts via sensory cues. Currently, we are running pre-experiments to find the most promising sensory cues before we start opening the artificial roosts. As a model species we chose wrinkled-lipped bats (Trachops cirrhosus). Using Wildlife Acoustic SM4s we recorded individuals in their roosts during the early morning hours when the individuals start coming back to their roosts. As groups of T. cirrhosis usually roost in relatively stable groups, we assume that conspecifics attract each other via calls. We then caught individuals in their roosts and brought them to a flight arena where we had set up two artificial roosts. From one we played back purely social calls (contact calls), from the other a mix of contact and echolocation calls was broadcasted. So far we found that although the contact calls are more attractive to the individuals (as indicated by the number of approaches to the referring artificial roosts), in the end the bats preferred to stay inside the roosts where the mixture of calls had been broadcasted. Moreover, we tested if olfactory cues also might be effective in attracting the individuals. As T. cirrhosis is usually roosting in mixed species groups, e.g. with Micronycteris spp., we tested pure T. cirrhosis feces against a feces mix of different bat species that we had freshly collected inside the roosts. It seems that the T. cirrhosis individuals prefer feces of their own species. We will continue testing further sensory cues until we have a large enough sample size to ensure that we collected the best working ones. After that we will start opening the artificial roosts in the wild to experimentally test which sensory stimulus (acoustic, olfactory or a mixture) is most reliable in attracting wild bats to novel roosts.
With our project, Effectiveness of artificial roosts for Neotropical bat species" we want to attract bats to artificial roosts via sensory cues. For this aim, we use fringe-lipped bats (Trachops cirrhosus) as study species. Currently, we are still running pre-experiments to find the most attractive acoustic and olfactory cues. This has turned out to be more challenging than previously thought. To find optimal cues, we are running pre-experiments in a flight cage where individual T. cirrhosus can select between roosts with different acoustic cues (playbacks of T. cirrhosus social calls vs. a mix of social and echolocation calls). However, we needed to change the acoustic set-up several times and are still searching for the best possible acoustic design. Because finding an attractive sensory lure is so critical to the success of the project, we are investing considerable time and care in these pre-experiments to ensure a well-working study design once we open the artificial roosts. Additionally, we have started to conduct a second type of pre-experiments in old bunkers that are frequently used as roosts by wild-ranging T. cirrhosus. During the last months, we rarely recorded any individuals of T. cirrhosus with the SM4s inside the bunkers but our impression is that the individuals nevertheless preferred those bunkers where we played back a mix of social and echolocation calls of conspecifics compared to control bunkers without any playbacks. We will need more time and more recordings of individuals inside the bunkers to evaluate this statistically.
During the last months we were very successful and could record many videos from the pre-experiments, which aim to evaluate the most promising sensory cues to be tested in the field.
I am currently analysing the videos, which takes a lot of time as one video lasts 8 to 12 hours. In a flight cage we have set up two artificial roosts from where different sensory cues are displayed (e.g., pure Trachops social calls vs. a mix of social and echolocation calls). For the video analysis I evaluate which roost/sensory cue is visited most often and which eventually serves as roost, i.e. where does the bat stay in the end. I will then run the according statistics.
We are about to finish the pre-experiments within the next one or two weeks. My colleagues could catch a lot of Trachops individuals for the pre-experiments and most of them were cooperative. When broadcasting bat calls with a BatLure from out of artificial roosts inside a flight cage, it seems that the Trachops prefer the mixed calls (social + echolocation calls) over the pure social calls. This would be close to what happens in nature, where there are also no pure calls of a certain type (social vs. echolocation call). We will need a few more of these pre-experiments to get significant values.
Situation is different when we are testing olfaction cues in further pre-experiments. Here, the bats randomly choose one of the presented olfactory cues (pure feces from Trachops vs. a mix of feces from Trachops and other bat species that can be found roosting together). It is difficult to say if olfaction does not play a role for roost selection or if the Trachops simply do not care. I hope that the field-experiment will tell us more on this question. For the field experiment, we are as well going to use a feces mix (Trachops + other bat species), as this resembles the most natural situation.
Finally, as we are so close to start with the field experiment, we are testing the set-up within the artificial roosts in our study sites and how to arrange the devices inside the roosts (e.g., we need to avoid that the SM4s constantly record the bat calls emitted by the BatLures. I have attached a short graph on how we are planning the set-up). This way, we will be able to directly start with the field-experiment once the last pre-experiment has been conducted.
I am very confident that we can finally start with the field-experiment mid of November.
Habitat loss, conversion and fragmentation have posed major threats to bat species worldwide. This is especially true for bats in tropical rainforests. Many tropical bat species rely on intact forests not only for foraging but also, critically, for roosting. Several studies from Europe and North America have tested the effectiveness of artificial bat roosts (ABRs) as surrogates for the tree cavities found in older growth forests, critical roosting resources that are often lacking in forests suffering from anthropogenic impact. In contrast, in the tropics ABRs have rarely been offered to bats; knowledge on their effectiveness is lacking. Our project, “Effectiveness of artificial roosts for Neotropical bat species,” aims to investigate natural colonization of ABRs (Fig. 1), and to test whether the addition of bat-specific sensory stimuli enhance the roost colonization process. In addition to daily acoustic and visual monitoring of ABRs, we conducted field experiments with sensitive gleaning phyllostomids. We focus on Neotropical fringe-lipped bats (Trachops cirrhosus) as a model species to investigate which stimuli effectively attract individuals to ABRs. Knowledge gained from these investigations will offer valuable insight for conservation strategies that can be widely applied.
We hypothesized that 1) certain bat species would colonize ABRs more quickly than others and 2) these colonization processes might reflect succession patterns, with certain species depending on others for roost discovery: highly exploratory species colonizing ABRs first, less exploratory species following only once others had become established within a roost. 3) We further hypothesized that species which are less likely to use ABRs are at more risk from habitat loss, because they are more likely to rely on specific characteristics for roost finding, and are less flexible in adapting to changing environmental features. We predicted that by introducing sensory lures we could help close this gap, making new, artificial roosts attractive to sensitive species as well. We specifically predicted that multi-modal sensory lures (acoustic + olfaction cues combined) would be more effective in attracting bats than uni-modal lures (acoustic or olfactory cues alone), which in turn should be more effective than controls with no added sensory cues. Finally, we predicted that ABRs would be more effective when situated in disturbed forests where natural roosts are rare.
The project is located in the secondary tropical forests of Soberanía National Park near Gamboa, Panama (28 ABRs; Fig. 2), and in Osa, southwestern Costa Rica (40 ABRs). We are currently conducting experiments in the Panama study site; we focus on these results for this report. Moderate to more extensive land use characterizes the chosen study areas. For a comparative approach between disturbed and intact forests, the same experiments will be conducted on Barro Colorado Island, which is the site of more pristine, undisturbed forests. Afterwards, we will repeat the experiments in Costa Rica to investigate if the results transfer to other regions.
Over 70 species of bats can be found in the forests around Gamboa, including the fringe-lipped bat, Trachops cirrhosus (Fig. 3), which is known for eavesdropping on the mating calls of its frog and insect prey. It is particularly known for feeding on the túngara frog, Engystomops pustulosus.
To select the sensory stimuli most effective at attracting our focal bat, T. cirrhosus, we tested different acoustic and olfactory cues. From earlier studies we knew that individuals of T. cirrhosus can be attracted with acoustic lures broadcasting the mating songs of túngara frogs. Such playbacks have been used for behavioral experiments in the context of foraging, but did not make sense in the context of roost finding. For roost attraction we instead used the calls of conspecifics. Using mist nets, we captured T. cirrhosus from their natural roosts and foraging sites around Gamboa, and brought them to our lab. After collecting standard measurements (e.g. forearm, weight, reproductive status, etc.) and marking them with PIT-tags for individual recognition, we fed them fish and offered water ad libitum. At dusk we put the bats in a flight cage in which we had set up an artificial roost. As soon as the bats had started to occupy the artificial roost, we recorded their calls (Avisoft Bioacoustics, Germany: USGH with condenser microphone CM16; Wildlife Acoustics, US: SM4BAT FS with SMM-U1 external ultrasonic microphones). We then released the bats into their natural habitat again.
To test which types of calls attracted bats to the roost, we conducted a series of behavioral choice experiments with new individuals (Fig. 4). We set up two artificial curtain roosts inside the flight cage and placed one ultrasound loudspeaker (Avisoft Bioacoustics, Germany: UltraSoundGate Player 416 H with Ultrasonic Dynamic Speaker Vifa; Apodemus, Netherlands: BatLure) behind each curtain. Each loudspeaker played back a different type of bat call. The test stimuli included social calls, echolocation calls, and a mixture of echolocation and social calls.
Similarly, we tested bat responses to different olfactory stimuli. We first collected feces from T. cirrhosus individuals in the lab and from a natural roost exclusively used by T. cirrhosus. These pure T. cirrhosus feces were tested against a mix of feces from species that commonly roost together (e.g., T. cirrhosus, Micronycteris spp. and Saccopteryx spp.), freshly collected from natural roosts. We placed each of the two olfactory stimuli in one of the two arms of a Y-maze and placed a T. cirrhosus individual in the starting arm (Fig. 5). Beginning at approximately midnight each bat had 7 hours to decide if it stays in the starting arm, in the arm that contained pure Trachops feces, or in the arm with the mixed species feces.
In all experiments the different stimuli were randomly allocated to one of the two sides. All experiments were filmed with camcorders and infrared lights to see for which stimulus the bats finally decided as indicated by their final choice in the early morning hours.
ABRs are located in sets of four in the same area (plots of 100 m²) to minimize the effects of environmental variation on colonization rates. Within a set we randomly assigned each ABR to one of four treatments to determine what sensory stimuli best attract bats. ABRs were fitted with (1) an acoustic lure (Apodemus, Netherlands: BatLure) broadcasting the bat calls found to be most attractive in our lab experiments, (2) an olfactory lure, using the fecal cues found to be most attractive in our lab experiments, (3) a multi-modal lure (both acoustic + olfactory lures), and (4) no sensory lures, as a control. ABRs are monitored daily by visual inspection and acoustically using ultrasonic recorders (Wildlife Acoustics, US: SM4BAT FS with SMM-U1 external ultrasonic microphones) to assess the colonization process. We opened the first set of ABRs November 2018. We plan to continue opening the remaining ABRs in groups of four as described above, and monitor each set for a minimum of 8 weeks.
We recorded echolocation (Fig. 7) and social calls (Fig. 8) from T. cirrhosus individuals. By presenting these calls to new individuals (n = 10), we were able to select attracting (and not repelling) social calls. When testing these attracting social calls against echolocation calls, we found that the bats are generally more attracted by the social calls than by echolocation calls as indicated by the number of approaches to one of the two artificial roosts inside the flight cage. However, after initial approach bats were reluctant to stay inside artificial roosts. We then tested the same social calls against a combination of echolocation and social calls. Still, the bats approached more often to roosts where the social calls were presented. However, when it came to roosting, the bats preferred to stay in the roost with the combination of echolocation and social calls. While these results are preliminary and we are continuing to run tests with more individuals, this is a strong hint that the bats prefer the most natural situation where individuals inside a roost display a mixture of echolocation and social calls and not only one call type.
Regarding the olfaction stimuli, the results from the preliminary experiments are less clear as the tested individuals (n = 6) randomly selected pure T. cirrhosus feces or the feces mix. Because a mixture of feces from different species most closely resembles natural conditions in many of the roosts, we decided to use the feces mix as olfactory stimulus in the field-experiments.
We currently only have one set of opened ABRs, so it is too early to draw conclusions from the field experiments. We do see some interesting preliminary findings, however. As predicted, acoustic monitoring with SM4s shows the highest bat activity at the ABR where acoustic and olfactory stimuli are presented together, followed by the ABR with acoustic stimuli alone, which is in turn followed by the ABR with olfactory stimuli alone. Lowest bat activity was measured at the control ABR which had no sensory lures.
We were excited to see that not only did bats inspect the ABRs as evidenced by the acoustic recordings, they also very quickly moved in. We found our first bat residents 5 days after opening the roosts. During our daily visual checks of the roosts, we have found a total 12 Micronycteris (gleaning insectivorous bat), 2 Glossophaga (nectarivorous bat), and 1 Carollia (frugivorous bat) roosting in the ABRs since roost opening. These species are known to be exploratory and rapid roost colonizers, so it confirms our predictions that they would find our roosts first. We hope that with more time, and with these pioneer species residing in the ABRs and thus also acting as attractant lures, the more sensitive bat species such as T. cirrhosus will also find these new roosting resources. Opening the other ABRs and monitoring colonization of these roosts by different species will enable us to better implement ABRs in tropical forests, thereby protecting those vulnerable bat species which are affected most by roost destruction. By doing so, we will be able to make concrete recommendations for applied conservation projects, helping bats recover from anthropogenic impacts.
For all their help in the field and/or ideas and suggestions we are deeply grateful to Detlev Kelm, Nikolai Meyer, Ram Mohan, Michelle Nowak and Adriana Tapia. We cordially thank Wildlife Acoustics for providing us with four SM4BAT FS and associated acoustic equipment, especially Alexandra Donargo for her help throughout this project.