▪ Abstract Extra-pair paternity (EPP) is extremely variable among species of birds, both in its
frequency and in the behavioral events that produce it. A flood of field studies and …

Previous studies have shown that some female black-capped chickadees (Poecile
atricapillus) solicit copulations from males that rank higher in winter flocks than their social …

This study investigates the importance of mate guarding for males and females in the
facultatively polygynous blue tit Parus caeruleus. We present observational data in …

Abstract. Several of the reported costs and benefits of testosterone-induced changes in
avian breeding behaviour may be mediated by the hormone's effects on spatial activity …

METHODS I performed the two experiments during the summers of 1990 and 1991 as part of
a larger study of reproductive behavior in a population of red-winged blackbirds located just …

In a number of passerine bird species, mated males sing at dawn and this song activity
peaks in the fertile period of the mate. We present the hypothesis that an important function …

For many species of animals, mating serves more than a procreative function, and much
more than gametes are exchanged between partners (Wilson, 1978). Females are expected …

In many socially monogamous birds, males maintain close proximity to their mates during
the fertile period. This is often considered an effort on the male's part to prevent other males …

We carried out DNA fingerprinting on 553 young (130 broods) great reed warblers
(Acrocephalus arundnaceus) in 1987–1991. In the study population, where 40% of the …

We removed the mates of ten male black-capped chickadees (Pares atricapillus) during the
nest-building period to determine the effect of female presence on dawn singing. During the …