Standing on the Side of Science, Freedom, and Democracy: A Message from Our CEO
The Mariana Crow (Corvus kubaryi), locally known as Aga, is a critically endangered forest crow found only on Guam and Rota. With fewer than 200 individuals remaining, urgent conservation efforts are underway, including a captive rear-and-release program that began in 2016. This program hand-raises chicks from wild-collected eggs but lacks natural parental vocal interaction—an element known to affect long-term social behavior and reproductive success in corvids.
Characterize nesting-related vocalizations of wild Aga.
Identify stage-specific parent-offspring vocal exchanges.
Compare wild and captive-reared juvenile vocal behavior.
Wild Aga Nests:
20 nests monitored with SM3/SM4 ARUs and SMM-A2 extended microphones.
Over 4,160 hours of audio collected from nests (7 to 67 days each).
Recording times adjusted to capture early morning calls and improve frequency range (44.1kHz–48kHz).
Vocalizations were detected using Kaleidoscope Pro software.
Captive-reared Chicks:
13 chicks monitored from hatching through 2 months, with follow-up at 5–8 months.
390 hours of recordings collected during indoor feeding and outdoor aviary sessions.
Post-20-day analysis excluded due to mixed vocal environments.
Selected acoustic features (e.g., peak frequency, duration) analyzed using Raven Pro and R statistical software.
Applied ANOVA and Bonferroni corrections to test effects of age, sex, and weight.
Development of Captive-reared Vocalizations
Figure 1: Vocalizations per hour at each of nine AÌga nests. Values represent percent of vocalizations during each hour, totaling 100% for each nest. As the hour bars represent the sum of percent for each site in that hour, some hours exceed 100%.
Figure 2: Peak frequency (Hz) measurements of two male and two female captive-reared AÌga at four time-points in development. While frequency generally decreases with age, males and females see the highest rate of change at different ages.
Conclusion