Temporal pattern and efficiency of escorting behaviour in the Spotless Starling (Sturnus unicolor).

Published:

Volume 45(2), December 1998. Pages 143-150.

Language:

English

Keywords:

escorting behavIour, extra-pair fertilisation, fertile period, mate guarding, Sturnus unicolor.

Abstract:

The study of escorting behaviour by the Spotless Starling Sturnus unicolor was performed in a nest-box colony in a Spanish dehesa (extensively grazed open holm oak woodland). Daily observations realised on ten focal pairs showed that escorting behaviour began 4-5 days before egg laying and declined markedly between the second and third days of the laying period. Males followed their females more than the reverse, and spent up to 90% of time in the colony with the female during her fertile period. Arrivals of both mates at the colony were significantly more synchronous during the fertile period. Escorting males chased off actively other males to prevent them approaching their mate. Copulations occurred mostly during the escorting period. As males escorted their females only during the fertile period, it is suggested that escorting can be interpreted more as mate guarding behaviour aimed at avoiding extra-pair fertilisations than at protecting the pair bond. Females often succeeded in escaping their mate vigilance. Thus, our data suggest that males guarded in order to keep other males away from their female, but also to prevent females from approaching other males.