The limits of egg recognition: testing acceptance thresholds of American robins in response to decreasingly egg-shaped objects in the nest.

ABSTRACT: Some hosts of avian brood parasites reduce or eliminate the costs of parasitism by removing foreign eggs from the nest (rejecter hosts). In turn, even acceptor hosts typically remove most non-egg-shaped objects from the nest, including broken shells, fallen leaves and other detritus. In search for the evolutionary origins and sensory mechanisms of egg rejection, we assessed where the potential threshold between egg recognition and nest hygiene may lie when it comes to stimulus shape. Most previous studies applied comparisons of egg-sized objects with non-continuous variation in shape. Here, instead, we used two series of three-dimensional-printed objects, designed a priori to increasingly diverge from natural eggs along two axes (width or angularity) of shape variation. As predicted

SUBMITTER: Hauber ME 

PROVIDER: S-EPMC7890492 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature