NO RELATIONSHIP BETWEEN TERRITORY SIZE AND THE RISK OF CUCKOLDRY IN BIRDS

It has been suggested that male birds adjust their territory size in o rder to prevent potential intruders from gaining extra-pair copulation s. The risk of cuckoldry is supposed to be highest when the distance b etween a female and the neighbouring males is shortest. This paper des cribes the variation in territory size of the chiffchaff, Phylloscopus collybita, in relation to the breeding cycle. Contrary to the risk of cuckoldry hypothesis, chiffchaff territories were larger prior to the fertile period of the females and at a minimal size during the fertil e period. A review of the literature shows little, if any, evidence of a peak in territory size during the fertile period of the females for most species studied. It is suggested that territoriality is in need of an operational definition. Without such a definition, it is difficu lt to make and test predictions about the adaptive basis of variation in territory size. (C) 1998 The Association for the Study of Animal Be haviour.