Great Tit Parus Major Population Research Articles

Genetic evidence for extra‐pair fertilizations in a monogamous passerine, the Great Tit Parus major

The incidence of extra‐pair paternity in a Great Tit Parus major population at Wytham Wood, Oxford, in 1985–1987 was determined using two polymorphic allozymes. In 831 nestlings from 94 broods, 27 genetic exclusions were detected in 25 (3%) nestlings from 16 broods. Seven (44%) of these broods contained offspring that excluded the putative male parent from being the genetic parent. The distribution of exclusion types indicated that excluded offspring were the result of fertilizations by extra‐pair males and not of egg‐dumping. The true frequency of extra‐pair paternity was estimated as 14% of offspring. These results suggest a mixed reproductive strategy for males in which they breed mo‐nogamously whilst simultaneously seeking extra‐pair matings with females of other pairs.

The effect of direct supplementary feeding of nestlings on weight loss in female Great Tits Parus major

Experimentally hand‐feeding nestlings of enlarged (+3 nestlings) broods reduced female weight loss during the nestling period in a single‐brooded Great Tit Parus major population in Scotland but did not affect nestling size. The result is consistent with the existence of a trade‐off in parental care between reproductive costs and benefits.