Greater Scaup (Aythya marila) Allen T. Chartier
increased from 12-13 to 14-20. The overall number of individuals wintering on the Great Lakes also seems to be increasing, which may be related to ice cover throughout the winter, and possibly other causes.
During the MBBA I period, five Upper Peninsula and eight Lower Peninsula counties reported Greater Scaup. Most observations were of one to five birds per sighting, but one observation was 50 birds in St. Clair County. No records of Greater Scaup were submitted from Hamilton, ON 3/14/2009 © Greg Schneider Monroe County during MBBA I, and none were
reported in the summer Michigan Bird Surveys Not easy to distinguish from its close relative, from 1983-1988. From 1993 and during the the Lesser Scaup, the Greater Scaup is a fairly MBBA II period (through 2008), however, common migrant and fairly common to common summering Greater Scaup were reported in the winter resident in Michigan. Michigan harvests Michigan Bird Survey in every year. The more Greater Scaup than any other state in the majority of summer records (15 of 24) were Mississippi Flyway (B. Avers-DNRE, pers. from Pte. Mouillee State Game Area, Monroe comm.). Migrants occur primarily on the Great County, where they were reported annually Lakes and occasionally larger inland lakes from 1993-2008. The number reported has (Payne 1983, Chartier and Ziarno 2004). The ranged from two individuals in 2005 (Byrne primary breeding grounds are in Alaska (Kessel 2006) to 15 individuals in 2003 (Byrne 2004). et al. 2002). In the Great Lakes region, the These reports have often included both males Greater Scaup breeds primarily in the Hudson and females, meeting the atlas definition for Bay lowlands of Ontario in wetlands in taiga, Possible breeding. A few other individuals were tundra, and muskeg (Kessel et al. 2002, also reported in early June during the MBBA II Badzinski 2007). period from Bay, Oakland, St. Clair, Muskegon, Alpena, Delta, and Houghton Counties, but Depending on ice cover, variable numbers of were likely tardy migrants. The increasingly Greater Scaup have wintered on Lakes Erie and frequent observations of summering pairs and Ontario since the 1980s (Kessel et al. 2002). groups of Greater Scaup should be monitored The peak number found on Christmas Bird carefully in the future for a potential first Counts (CBCs) in Michigan since 1993 was breeding record for the state. 20,917 in the winter of 2005-2006 (Palmgren 2006). While these counts often occur before The population and trends of Greater Scaup are Lakes Erie and St. Clair freeze up completely, largely unknown as surveys (mainly aerial) do other high counts have been recorded later in not distinguish between the Greater and Lesser winter if these lakes do not freeze up Scaup. The continent-wide breeding ground completely. These later-season high counts population estimate in 2001 was 634,000, while include 7,000 on 16 February 1995 on Lake St. the total U.S. midwinter estimate for 2000 was Clair (McWhirter 1995) and 4,750 on 21 192,000 (Kessel et al. 2002). It is estimated that February 2008 on the Detroit River at Grosse approximately 11% of the continental scaup Ile, Wayne Co. (Wuepper 2008). From 1993- population, estimated at 4.2 million in 2009 2008, the average number of CBCs recording which represented a decline of 18% from the Greater Scaup in Michigan each year has
© 2011 Kalamazoo Nature Center Greater Scaup (Aythya marila) Allen T. Chartier long-term average, are Greater Scaup (USFWS Dept. of the Interior, Washington D.C., 2009). Better survey methods for distinguishing USA. Greater from Lesser Scaup are definitely needed Wuepper, J.T. 2008. Michigan Bird Survey: in order to ascertain its true status. Winter 2007-2008 (1 Dec – 29 Feb). Michigan Birds and Natural History 15(3): Literature Cited 100-123.
Badzinski, S.S. 2007. Greater Scaup (Aythya Suggested Citation marila). In Cadman, M.D., D.A. Sutherland, G.G. Beck, D. Lepage, and A.R. Couturier Chartier, A.T. 2011. Greater Scaup (Aythya (eds.). 2007. Atlas of the Breeding Birds of marila). In Chartier, A.T., J.J. Baldy, and Ontario, 2001-2005. Bird Studies Canada, J.M. Brenneman (eds.). 2010-2011. The Environment Canada, Ontario Field Second Michigan Breeding Bird Atlas. Ornithologists, Ontario Ministry of Natural Kalamazoo Nature Center. Kalamazoo, MI. Resources, and Ontario Nature. Toronto, Accessed online at:
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