title: Unpredictable environments lead to the evolution of parental neglect in birds.
abstract: A nest of begging chicks invites an intuitive explanation: needy chicks want to be fed and parents want to feed them. Surprisingly, however, in a quarter of species studied, parents ignore begging chicks. Furthermore, parents in some species even neglect smaller chicks that beg more, and preferentially feed the biggest chicks that beg less. This extreme variation across species, which contradicts predictions from theory, represents a major outstanding problem for the study of animal signalling. We analyse parent-offspring communication across 143 bird species, and show that this variation correlates with ecological differences. In predictable and good environments, chicks in worse condition beg more, and parents preferentially feed those chicks. In unpredictable and poor environments, parents pay less attention to begging, and instead rely on size cues or structural signals of quality. Overall, these results show how ecological variation can lead to different signalling systems being evolutionarily stable in different species.
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
authors.forename: Shana M
authors.initials: SM
authors.lastname: Caro
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
authors.forename: Ashleigh S
authors.initials: AS
authors.lastname: Griffin
authors.affiliation: Behavioural Ecology Group, Department of Animal Sciences, Wageningen University, PO Box 338, 6700 AH Wageningen, The Netherlands.
authors.forename: Camilla A
authors.initials: CA
authors.lastname: Hinde
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
authors.forename: Stuart A
authors.initials: SA
authors.lastname: West
mesh_terms: D000819:Animal Communication; D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D001717:Birds / Q000502:physiology*; D003463:Cues; D004777:Environment; D013045:Species Specificity