Date: May 2, 2019
Source: Oxford University Press USA
A new
study in The Auk: Ornithological Advancessuggests that some birds
prioritize social information over visual evidence when making breeding
choices.
The
quality of an environment can be difficult for a bird to assess and, therefore,
continuously gathering information is a good way to stay up-to-date with
breeding conditions. In this field study, researchers tested how the wild Zebra
Finch (Taeniopygia guttata) is
attracted to successful nest sites. They presented the Zebra Finch with
different visual or acoustic cues in nest boxes, simulating the presence of
small or large broods, in order to test how birds assess the quality of a
potential breeding site.
When
discussing the costs and benefits of social information, scientists often argue
that socially acquired knowledge is less reliable and more prone to deception.
The sounds made by nesting birds, however, are honest indicators of the number
of chicks. Predators can use these cues to locate nests. While the calls of
chicks serve as signals for the parents and siblings and (inadvertently) also
as cues for predators, it is unknown whether chick calls can also function as
cues for prospective breeders.
Researchers
here aimed to test which social cues from the nests of Zebra Finches attract
other Zebra Finches. In two separate experiments, they presented wild Zebra
Finches with either acoustic cues (playback of chick calls) or visual cues
(eggs) with either small or large broods. Using playbacks of chick calls or
nests with unhatched eggs, respectively, allowed them to completely discern
brood size from parental activity.
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