title: Realized reproductive success of polygynous red-winged blackbirds revealed by DNA markers.
abstract: Hypervariable genetic markers, including a novel locus-specific marker detected by a mouse major histocompatibility complex probe, reveal that multiple paternity is common in families of polygynous red-winged blackbirds (Agelaius phoeniceus). Almost half of all nests contained at least one chick resulting from an extra-pair fertilization, usually by a neighboring male. Genetically based measures of reproductive success show that individual males realize more than 20% of their overall success from extra-pair fertilizations, on average, and that this form of mating behavior confounds traditional measures of male success. The importance of alternative reproductive tactics in a polygynous bird is quantified, and the results challenge previous explanations for the evolution of avian polygny.
authors.forename: H L
authors.initials: HL
authors.lastname: Gibbs
authors.forename: P J
authors.initials: PJ
authors.lastname: Weatherhead
authors.forename: P T
authors.initials: PT
authors.lastname: Boag
authors.forename: B N
authors.initials: BN
authors.lastname: White
authors.forename: L M
authors.initials: LM
authors.lastname: Tabak
authors.forename: D J
authors.initials: DJ
authors.lastname: Hoysak