Begging calls provide social cues for prospecting conspecifics in wild zebra finches

Social information can spread fast and help animals adapt in fluctuating environments. Prospecting on the breeding sites of others, a widespread behavior, can help to maximize reproduction by, for instance, settling in the same area as other successful breeders. Previous studies have shown that successful broods have the highest number of prospectors and that they are visited most when offspring in nesting sites are already old, making the information more reliable. In this field study, we experimentally tested how prospectors are attracted to successful nest sites. We presented wild Zebra Finches (Taeniopygia guttata) with different visual or acoustic cues in nest boxes, simulating the presence of small or large clutches or broods. More Zebra Finches visited experimental nests that were associated with playback recordings of begging calls of large broods (7 chicks) as opposed to begging calls of small broods (3 chicks) and controls (white noise and silence). On the other hand, visual cues (nests with different numbers of eggs or rocks), representing nests at early stages, did not influence either the probability of visits, nor number or duration of visits. We present the first evidence that begging calls of chicks in the nest, a signal intended for kin communication, can also provide social information to unrelated prospecting conspecifics. This information could potentially be used for a fast initial assessment of the quality of a breeding site.