Time constraints may pace the ontogeny of movement behaviour

Anne G. Hertel, Ron Efrat, Korin Reznikov, Nir Sapir, Oded Berger-Tal, Thomas Mueller

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


During early development, juvenile animals need to acquire a diverse behavioural repertoire to interact with their environment. The ontogeny of animal behaviour, is paced by the motivation to improve, e.g. internal clocks, and limited by external constraints, e.g. weather conditions. We here evaluate how naive Egyptian vultures (Neophron percnopterus) improve in locomotor performance, measured as daily maximum displacement, prior to their first migration under three different time constraint regimes: we compared wild hatched vultures, migrating one month after fledging, with captive-hatched vultures, released in spring four months or in winter nine months before migration. We found that the time until migration paced the development of movement behaviour: wild birds rapidly increased displacement distances within the first two weeks after fledging, while spring and winter released vultures delayed movement increases by two and four months, respectively. Under relaxed time constraints captive-hatched vultures displayed diverse functional forms of performance enhancements and therefore great variability in individual ontogeny of movement behaviour. While weather conditions in winter could limit flight movements, some birds indeed moved immediately after their release, indicating that weather may not be limiting. Our findings promote the idea that relaxed ecological constraints could uncover hidden phenotypic flexibility in ontogeny, which could present a greater potential for adaptability under environmental change than currently expected.

Original languageEnglish
Article number20222429
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1996
StatePublished - 12 Apr 2023


  • behavioural development
  • egyptian vulture
  • locomotor performance
  • migration
  • soaring flight

ASJC Scopus subject areas

  • General Agricultural and Biological Sciences
  • General Environmental Science
  • General Immunology and Microbiology
  • General Biochemistry, Genetics and Molecular Biology


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