Realized Reproductive Success of Polygynous Red-Winged Blackbirds Revealed by DNA Markers

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 …