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.
The Role of Song Meters
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."
Advice for deploying Song Meters
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.
Results to Date
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.
As told to Wildlife Acoustics
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.