Variable but predictable prey availability affects predator breeding success: natural versus experimental evidence

A. Millon, B. E. Arroyo, V. Bretagnolle

Research output: Contribution to journalArticle

28 Citations (Scopus)


Food supply is a major source of variation in breeding success for predators, and to what extent individuals are able to cope with temporal variability in food availability remains an outstanding question in life-history studies. We confronted the natural variation in clutch size and breeding success with results from a food supplementation experiment during egg formation, conducted over several contrasted years of natural food supply in an avian specialist predator, the Montagu's harrier Circus pygargus. This raptor mainly preys on common vole Microtus arvalis a cyclic microtine under temperate latitudes. Vole abundance together with timing of breeding accounted for most of the variance in clutch size and number of fledglings. Results from empirical and experimental data were overall in agreement. Fed pairs consistently increased clutch size compared with controls in all experimental years, whereas no effect of food supplementation on egg volume was detected. Supplemented pairs, however, did not fledge significantly more chicks than controls. The costs entailed by the increase in clutch size appear nevertheless to be limited compared with previous studies. Food supply seemed therefore to display sufficient predictability throughout a breeding season to afford individuals the opportunity to adjust their breeding effort to an optimal number of offspring, in agreement with Lack's anticipation hypothesis.

Original languageEnglish
Pages (from-to)349-358
Number of pages10
JournalJournal of Zoology
Issue number4
Early online date14 May 2008
Publication statusPublished - Aug 2008


  • circus pygargus
  • clutch size
  • Microtus arvalis
  • vole cycle
  • harrier circus-pygargus
  • fluctuating food conditions
  • kestrel falco-tinnunculus
  • population-cycles
  • rearing capacity
  • strix-uralensis
  • tengmalm owl
  • laying date
  • birds


Dive into the research topics of 'Variable but predictable prey availability affects predator breeding success: natural versus experimental evidence'. Together they form a unique fingerprint.

Cite this