Wybór partnera u kormoranów w warunkach ogrodu zoologicznego

Bibliogr. s. 78

Streszcz. pol.

Bibliogr. p. 78

S. [73]-78 : il. ; 27 cm

Study (1982-1997) in the small cormorants' colony of the Amsterdam Zoo addressed the question of what factors determine between-season divorce. The proportion of pairs splitting up the next year was 0.46, i.e. less than in wild populations. Low divorce rate could not be explained by the small population size. Computer simulations showed that if pair-formation in the zoo occurred at random, divorce rate would be higher. Occurrence of divorce was unrelated to previous breeding success or age of pair mates. The only variable that could predict divorce was the frequency of interactions of pair mates after breeding. Pair mates that were not seen together after breeding were more likely to split up the next year. Thus mate retention probably involved some process of choice by the partners. This led to the suggestion that mate retention in the wild is constrained, since contact between mates is lost during migration. We also found that extra-pair copulations (EPCs) played a role in the assessment and choice of the mate. Female Cormorants pursued EPCs mostly when they were presumably not fertile. Involvement in EPCs increased the probability that the female subsequently paired with the male concerned. It is proposed that EPCs may have the additional function of assessing the quality of potential mates for future pair-formation.

Referat wygłoszony na Second Meeting of the European Ornithologists' Union

P. [73]-78 : ill. ; 27 cm

Abstract in Polish