A higher perching position may permit males to more easily defend their territories, observe neighboring females for extra-pair mating opportunities and be vigilant for predators (Carlson et al.
Pre-dawn infidelity: females control extra-pair mating in superb fairy-wrens.
Females increase offspring heterozygosity and fitness through extra-pair matings
, male plumage coloration and sexual selection in Yellow Warblers (Dendroica petechia).
Several factors may be contributing to the lack of consistent identification of traits that are sexually selected through extra-pair mating.
However, studies that have been able to assign sires to most or all of the extra-pair young show that extra-pair mating often occurs between territorial neighbors (or within one territory; reviewed in Sardell et al.
2004a) suggested that high altitude Rufous-collared Sparrows likely have an extra-pair mating system and the sustained levels of testosterone may reflect a genetically polygynous population where males would be favored to have elevated concentrations of testosterone throughout the breeding season (Moore et al.
We emphasized that extra-pair mating systems result in increased male-male competition, but more than simply male/male aggression and territoriality.
This species' mating system is characterized by monogamy and biparental care, but extra-pair mating
(Yezerinac and Weatherhead 1997, Yezerinac et al.
Indeed, extra-pair copulations can be difficult to observe, and many researchers have used radio telemetry for following both male and female birds during their extra-territorial forays in an attempt to document extra-pair mating
behavior (Smiseth and Amundsen 1995, Neudorf et al.
For example, some males of a tropical congener species that forms permanent pair bonds may initiate duets in order to limit extra-pair mating
and divorce (Gill and Stutchbury 2005), and, in some passerine species that form lifetime pair bonds, both sexes may actively guard their mates (Hall 2000, Gill 2003).
he promiscuous nature of commonly monogamous female birds has puzzled researchers, but studies had earlier showed that the offspring of these so-called extra-pair matings
were bigger, had better immune response, and were more likely to survive.
and mate guarding in the Common Murre Uria aalge.