Increased Bufflehead ( Bucephala albeola ) Breeding Activity in Minnesota SUSAN N. E LLIS -F ELEGE 1, 4 , C ASSANDRA G. S KAGGS 1, 3 , and GREGORy A. K NUTSEN 2 1Biology Department, University of North Dakota, 10 Cornell Street, Stop 9019, Grand Forks, North Dakota 58202-9019 USA 2U.S. Fish and Wildlife Service, Glacial Ridge and Rydell National Wildlife Refuges, 17788 349th Street SE, Erskine, Minnesota 56535 USA 3Louisiana State University, School of Renewable Natural Resources, LSU Agricultural Center, Baton Rouge, Louisiana 70803 USA 4Corresponding author:
[email protected] Ellis-Felege, Susan N., Cassandra G. Skaggs, and Gregory A. Knutsen. 2017. Increased Bufflehead ( Bucephala albeola ) breeding activity in Minnesota. Canadian Field-Naturalist 131(4): 338 –343. https://doi.org/10.22621/cfn.v131i4.1963 Buffleheads ( Bucephala albeola ) predominantly nest in the boreal forests and aspen parklands of Canada and Alaska. Historically, Buffleheads were common migrants but not summer residents in Minnesota. However, recent observations in Minnesota and surrounding states suggest increased breeding activity in the region. In 1978, the first Bufflehead brood in Minnesota was recorded at East Park Wildlife Management Area. Annually, Agassiz National Wildlife Refuge (NWR) has conducted pair and brood surveys, with species-specific records available from 1990 to 2014. We report an increase in numbers of Bufflehead breeding pairs and broods at Agassiz NWR and new pair observations in surrounding areas. Key Words: Breeding range; Bucephala albeola; Bufflehead; cavity nesting; expansion; Great Plains; upper midwest Introduction Recent observations have documented Bufflehead Buffleheads ( Bucephala albeola ) are a secondary breeding activity in the southern half of Minnesota, in - cavity-nesting species that frequently use the cavities of cluding a 2012 brood in Cottonwood County in south - Northern Flickers ( Colaptes auratus ) and, to a lesser ex - ern Minnesota (Pfannmuller et al.