For most avian species, social behavior is critically important for survival and reproductive success. Many social behaviors in birds are culturally transmitted, and as bird populations decline across the globe, important elements of these behaviors may be lost. The Hawaiian crow or ʻalalā, Corvus hawaiiensis, is a socially complex avian species that is currently extinct in the wild.

As in other oscine passerines, vocalizations in the ʻalalā may be culturally transmitted. We compared the vocal repertoire of three of the last four wild ʻalalā pairs from the early 1990s to three current captive pairs at the Keauhou Bird Conservation Center in Volcano, Hawaiʻi to determine how acoustic behavior has been affected by changes in their social and physical environment.

Our results showed that measures of acoustic richness and diversity were similar between the aviary and wild population, however, there were some very notable changes in call rates as well as the types of calls being made. We found that the wild ʻalalā had a significantly higher call rate (calls per minute) than the ʻalalā in the aviaries. There were also repertoire differences, which included the loss of alarm and the complete loss of broadcast/territorial calls in aviary ʻalalā. Our results show how socially learned behaviors may change over relatively short periods for an entire species. Understanding how the vocal repertoire and the functional context of vocalizations change may provide useful information for ongoing efforts to reintroduce the ʻalalā into the wild.

Read abstract or the links below to read full article:
phys.org/news/2017-01-alala.html

UH Hilo Stories: Climate Change Research at UH Hilo: Tree rings and Bird song (February 21, 2017)
hilo.hawaii.edu/news/stories/2017/02/21/climate-change-research-at-uh-hilo-tree-rings-and-bird-song/

American Association for the Advancement of Science (AAAS) Science Update (Podcast): Endangered Crow Calls (February 15, 2017)
www.scienceupdate.com/2017/02/call/