Mating system and social behavior of rusty blackbirds on Yukon Flats National Wildlife Refuge

Thesis (M.S.)--Humboldt State University, Natural Resources: Wildlife, 2013Embargoed for one year from date added to Humboldt Digital Scholar (2013-05-21).Released from embargo May 27, 2014.Many aspects of the breeding biology of the rapidly declining Rusty Blackbird (Euphagus carolinus) are unknown. I used behavioral observations and genetic analyses to gain a better understanding of their mating system, on Yukon Flats National Wildlife Refuge, Alaska, USA. Four polymorphic microsatellites developed for other avian species (QmAAT21, QmAAT37, Aph54, and Mp2-43) were used to assess rates of extra-pair paternity, polyandry, and egg dumping. Behavioral observations were employed to identify the social mating system and parental nest investment in relation to genetic contributions. In contrast to previous studies, my results indicate that male Rusty Blackbirds are not socially monogamous; over 15% of nests belonged to polygynous males. There was no evidence of polyandry or egg dumping, but extra-pair paternity (EPP) occurred in ??? 33% of nests. There was no correlation between the proportion of young that a male sired in a nest and either feeding rate or nest defense. Further studies are needed to investigate the role of environmental and social factors on mating systems and the rates of polygamy and EPP in Rusty Blackbirds