Pj. Weatherhead, Sequential mating patterns suggest extra-pair mating is not part of a mixed reproductive strategy by female red-winged blackbirds, P ROY SOC B, 266(1423), 1999, pp. 1027-1031
Citations number
19
Categorie Soggetti
Experimental Biology
Journal title
PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES B-BIOLOGICAL SCIENCES
Studies aimed at determining why female birds often produce offspring sired
by males other than their social mates generally compare traits of social
and genetic mates. Here I examine paternity patterns in nests of the same f
emale red-winged blackbirds (Agelaius phoeniceus) in successive breeding se
asons. Returning females preferentially selected their former social mates
as their new social mates when those males were present. However, paternity
patterns were much less consistent. A female's behaviour (faithful versus
unfaithful) in one year did not predict her behaviour the following year. F
emales unfaithful in successive years did not prefer the same extra-pair ma
les. Females unfaithful in one year that switched social mates the next yea
r did not preferentially choose their former extra-pair mates as their new
social mates. By switching genetic mates, females did not generally improve
the quality of their mates. These results, together with previous analyses
, suggest that female blackbirds in this population have little control ove
r extra-pair mating. Although females may benefit from extra-pair mating be
cause extra-pair males are generally longer lived, paternity patterns in th
is population are not consistent with extra-pair mating being part of a fin
ely tuned female reproductive strategy.