Referential calls coordinate multi-species mobbing in a forest bird community

Area of Science:

• Animal behavior
• Bioacoustics
• Ecology

Background:

• Birds use alarm calls to communicate threats to conspecifics.
• Referential communication, where signals convey specific information, is known in some species.
• The role of such calls in coordinating multi-species interactions is less understood.

Purpose of the Study:

• To investigate if Japanese great tits' mobbing calls convey specific predator information to other species.
• To determine if these calls influence the formation and behavior of mixed-species mobbing groups.

Main Methods:

• Playback experiments using recorded mobbing calls from Japanese great tits (Parus minor).
• Observation of heterospecific bird responses to snake-specific vs. non-snake-specific mobbing calls.
• Analysis of mobbing bird proximity and search behavior in response to different call types.

Main Results:

• Snake-specific mobbing calls attracted heterospecific birds closer to the sound source.
• Non-snake mobbing calls attracted heterospecific birds from a greater distance.
• Different call types elicited distinct mobbing formations and search behaviors in mixed-species groups.

Conclusions:

• Japanese great tits possess a referential mobbing call system that is understood by other bird species.
• Referential calls are crucial for coordinating complex, multi-species anti-predator behaviors.
• This study provides the first evidence of referential signals shaping the structure of mobbing parties.