From mating to laying: genetic and environmental variation in mating datesand prelaying periods of female pied flycatchers Ficedula hypoleuca

The duration of the period comprised between mating and the onset of laying and its correlates and consequences for aspects of female breeding perform ance are investigated in a population of pied flycatchers studied for 5 yea rs. That duration may represent a compromise between the selective pressure on females to breed as early as possible and the need for females attempti ng to breed to be in prime nutritional condition. It is shown that the dura tion of the prelaying period is shorter for late breeders, but is apparentl y unrelated to subsequent condition of the female and indices of breeding p erformance. A low, significant between-year repeatability (R = 0.16) in the duration of female prelaying period was detected. However, there was a lar ge component of environmental, as opossed to genetic, variation which may r eflect stochasticity affecting timing of breeding and age factors. Overall, the evidence supports models of strategic adjustment of breeding date to o ffspring prospects, rather than those based on condition-constrained breedi ng date.