Intra- and extra-pair copulations and female refusal of mating in Montagu's Harriers

We studied the mating behavior of Montagu's Harriers (Circus pygargus) and recorded the incidence of extra-pair copulations (EPC) and refusal of femal es to copulate. The average duration of copulations was 4.9 sec and they we re most frequent between 1000-1400 H. Each pair averaged 105 successful cop ulations per clutch (range = 31-245). About 59% of 114 within-pair copulati on (WPC) attempts were unsuccessful and, in 14 cases, the female rejected i ts mate. For the majority of cases, the cause of copulation failure was not identified. While the frequency of copulation attempts was not correlated with food-pass frequency, the duration of copulations was influenced by the presence of food brought by the male. Copulation attempts peaked early in the breeding season (3 wk prior to the beginning of egg laying) and outside the fertile period of females. Successful copulations peaked early in the breeding season (wk 4) and during the females' fertile period (wk 1). Copul ation early in the breeding season may function to assess male competence i n Montagu's Harriers allowing a way for females to evaluate the quality of males. Refusal is an aspect of female behavior that could help us to unders tand if, and in what way, female choice is based on the capacity of the mal e to successfully transfer sperm.