Asymmetrical interspecific communication in avian mixed species colonies

Sympatric species derive benefits by attending to information conveyed by heterospecifics. We previously reported reduced vigilance among jackdaws (Corvus monedula) and lesser kestrels (Falco numanni) residing in mixed species colonies and conducted the present study to test for interspecific communication of threat associated with European magpies (Pica pica) as nest predators. After quantifying structural differences in jackdaw and lesser kestrel calls relative to European magpie versus non-predator models, we played back calls of jackdaws and lesser kestrels representative of the different model types to test whether receivers perceive threat-related variation in either conspecific or he…