COPULATORY-BEHAVIOR AND PATERNITY DETERMINED BY DNA-FINGERPRINTING INKESTRELS - EFFECTS OF CYCLIC FOOD ABUNDANCE

It has been proposed that mate guarding is the primary paternity insur ance in birds, and only those species in which the male is compelled t o leave his mate unattended during the fertile period resort to freque nt copulation as a means of assuring paternity. A higher frequency of both extra-pair copulation (EPC) and extra-pair paternity (EPP) has be en predicted in non-guarding species. These predictions were examined in Eurasian kestrels, Falco tinnunculus, breeding in western Finland. During the course of a 3-year vole cycle, the mean within-pair copulat ion frequency was 0.72 per h and the mean number of extra-pair intrusi ons 0.07 per h. The proportion of EPCs was only 1% of copulations. The within-pair copulation frequency was higher in a year of increasing f ood abundance (1991) than in the years of decreasing (1992) and low fo od abundance (1990), although the kestrel breeding density was lower i n 1990 than in 1991-1992. Males spent more time mate guarding in 1991- 1992 than in 1990 (overall mean 40%). Single-locus DNA profiling revea led EPP in 7% of 27 broods and 5% of 112 offspring in 1991 but none in 1990 or 1992 (19 and 29 broods, respectively). Kestrel males successf ully used both frequent pair copulation and mate guarding as complemen tary paternity guards. The low frequency of EPP may reflect the import ance of male parental care in determining the reproductive success of raptors. Females may jeopardize future aid from their mates by solicit ing EPCs from intruders. This strategy might markedly reduce female fi tness, because the male is the main provider for female and young from before egg laying until the late nestling period. (C) 1996 The Associ ation for the Study of Animal Behaviour