Alarm calling in Sri Lankan mixed-species bird flocks

Eben Goodale*, Sarath W. Kotagama

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

99 Citations (Scopus)

Abstract

Vocal alarm calls are important to the vigilance and likely the organization of mixed-species flocks, but community-wide studies of alarm calling in flocks are lacking. We investigated which species alarm-call, and the characteristics of their calls, in a large flock system of a Sri Lankan rainforest. We recorded naturally elicited alarm calls during several attacks by Accipiter hawks and while following flocks for 10 h. We then artificially elicited alarms by throwing a stick to the side of the flock, in a total of 70 trials at 30 flock sites. The Orange-billed Babbler (Turdoides rufescens) was the most frequent caller to both the artificial and natural stimuli, followed by the Greater Racket-tailed Drongo (Dicrurus paradiseus). Several other species also called, and multiple species often called to the same stimulus (in 23 trials, and in all of the hawk attacks). The species differed in their rapidity of response and in their sensitivity to different natural stimuli. Calls of the gregarious babbler usually provided a first, unreliable warning of an incoming threat, whereas later calls of other species emphasized the seriousness of the threat. We suggest that birds in mixed-species flocks may be particularly aware of aerial predators for two reasons: (1) a "numbers effect," whereby nongregarious species are more aware of predators when surrounded by large numbers of other species; and (2) an "information effect," whereby species differ in the information available in their alarm calls, leading to an accumulation of information in a mixed-species flock.

Original languageEnglish
Pages (from-to)108-120
Number of pages13
JournalAuk
Volume122
Issue number1
DOIs
Publication statusPublished - Jan 2005
Externally publishedYes

Keywords

  • Accipiter hawks
  • Alarm calls
  • Community ecology
  • Dicrurus paradiseus
  • Greater Racket-tailed Drongo
  • Mixed-species flocks
  • Orange-billed Babbler
  • Predator vigilance
  • Sri Lanka
  • Turdoides rufescens

Fingerprint

Dive into the research topics of 'Alarm calling in Sri Lankan mixed-species bird flocks'. Together they form a unique fingerprint.

Cite this