Aythya affinis

Status:  Common, locally abundant, regular spring and fall migrant statewide. Rare casual summer visitor statewide. Uncommon regular winter visitor west, south, and east, rare casual elsewhere.

Documentation: Specimen: UNSM ZM 7679, 11 Apr 1913 Lancaster Co.

Taxonomy:  No subspecies are recognized.

Changes since 2000:  Baldassarre (2014) stated that the total population of Lesser Scaup has “declined markedly” between 1974 and 2009; such declines, however, have largely gone undetected in Nebraska.

Spring:  Feb 3, 3, 6 <<<>>> Jun 16, 17, 19

Arrival occurs as frozen water bodies open with warming temperatures. Earlier dates are 60 on 27 Jan 2016 Lake Ogallala, Keith Co, 29 Jan 2012 South Sioux City, Dakota Co, and 1 Feb 1989 Douglas-Sarpy Cos. Peak numbers occur in late Mar and early Apr, and small numbers may persist into late May and early Jun. Late dates above are from southern and eastern Nebraska.

• High counts: 3650 in Lancaster Co 25 Mar 2001, 3400 in the eastern Rainwater Basin 17 Mar 2001, 3000 at Gavin’s Point Dam, Cedar Co 23 Mar and 10 Apr 2018, and 2880 at Crescent Lake NWR, Garden Co 25 Apr 1995.

Summer:  There is no conclusive evidence that this species breeds or has bred in Nebraska (Wayne Mollhoff, personal communication); currently the nearest regular breeding is in extreme northeast South Dakota (Tallman et al 2002). See Comments.

There are nevertheless numerous summer reports for the western Sandhills, notably for Garden Co, where there have been counts from Crescent Lake NWR of up to 48 on 16 Jun 1996 and 26 on 17 Jun and 12 Jul 1995; one was there 6 Sep 2012, and a male was at Oshkosh SL, Garden Co 2 Sep 1993 (Rosche 1994).

There are 26 additional summer (18 Jun-8 Sep) reports in northern and western Nebraska away from Garden Co, including counts of up to 20 at Gering SL, Scotts Bluff Co 24 Jun 1995, eight at Gordon SL, Sheridan Co 8 Jul 1994, and one at Scottsbluff SL, Scotts Bluff Co 9 Aug 2017.

There are several summer reports from the Rainwater Basin. Jorgensen (2012) cited 15 eastern Rainwater Basin reports 24 May-7 Aug, including eight birds at Harvard WPA, Clay Co 15 Jun 1998 and six in the region 28 Jun 2001. More recently, in 2005 up to seven were found in the region through 6 Aug.  At Funk WPA, Phelps Co there are reports 22 Jun 1996 and 19 Jul 1997, and there are several summer reports from Adams Co in the 1960s and, more recently, 30 Jun 1984.

Elsewhere, away from the Sandhills and Rainwater Basin, there are several summer (20 Jun-8 Sep) reports: six from Lancaster Co 12 Jun-17 Aug 1992-2006 and one at Branched Oak Lake, Lancaster Co 6-25 Aug 2017, three from Alma SL, Harlan Co 13 Jun-1 Sep 2004-2009, 30 Jun 2019 (2) Jefferson Co, 8 Jul 2001 (male and female) Seward Co, 3-9 Jul 2014 Sarpy Co, 9 Jul 1981 and 1 Aug 1986 Pierce Co, 11 Jul 2019 (2) York Co, and four from Douglas-Sarpy Cos 8-25 Aug 1980-2013.

Although this species undergoes a molt migration to favored lakes in its breeding range (Baldassarre 2014), there is no indication that such a location exits in Nebraska.

Fall:  Sep 9, 11, 13 <<<>>> Jan 14, 15, 15

Migration commences in late Sep, and peaks in late Oct to early Nov. There is an earler report of 15 at Crescent Lake NWR, Garden Co 2 Sep 2019.

• High counts: 3450 at Lake McConaughy, 31 Oct 2000 at Branched Oak Lake, Lancaster Co 8 Nov 2011, and 1846 in Lancaster Co 19 Nov 2010.

Winter:   Overwintering occurs at certain locations such as Scottsbluff SL, Scotts Bluff Co, Lake McConaughy and Lake Ogallala, Harlan Co Reservoir and nearby Alma SL, and, more recently, Carter Lake, Omaha. At Lake Ogallala, as many as 328 were present 1999-2000, Scottsbluff SL had up to seven over-wintering 2014-2015, Alma SL hosted 16 during winter 1999-2000, and at Carter Lake 2-4 wintered 2011-2012 and up to five in 2014-2015.

Overwintering reports elsewhere are of one at Pioneers Park, Lincoln 2014-2015, two at Bufflehead Pond, Buffalo Co 1994-95, eight at Holmes Lake, Lincoln 2015-2016 and 1-3 at Ta-Ha-Zouka Park, Madison Co 18 Jan-21 Feb 2019.

There are a few additional mid-winter (16 Jan-2 Feb) reports that may have been of overwintering birds: 1-4 on 11 Jan-4 Feb 2007 Lancaster Co, two on 14-16 Jan 2016 Dodge Co, 15 and 24 Jan 2016 Madison Co,  one in Lancaster Co 20 Jan 2019, 10 in southwest Sarpy Co 25 Jan 2020, one at Branched Oak Lake 28 Jan 2020, one at Lewis and Clark Lake, Cedar Co 2 Feb 2020, and an excellent count of 40 below Gavin’s Point Dam, Cedar Co 20 Jan 2018.

Comments:  It has generally been assumed that there is a small but persistent breeding population in southern Sheridan and northern Garden Cos (Ducey 1988, Johnsgard 2013), but the available reports cannot be substantiated (Wayne Mollhoff, personal communication). According to Mollhoff, reports of young at Crescent Lake NWR in 1978 and 1979 were estimates based on annual reports from the refuge of the number of adults present, not on young seen. An estimated 28 young were reported as produced in 1978 at Crescent Lake NWR, and the only evidence for 1979 was a statement by the refuge manager that “in 1979 the refuge maintained a summer population of about 20 adults, not all of which were likely breeding” (Roger Sharpe, pers. comm.). Ducey (1988) cited one breeding report, in Cherry Co in 1966, which appears to be based on Cornell Nest Record cards; Mollhoff searched the record cards at Cornell and found only records for Redhead in 1966 (Wayne Mollhoff, pers. comm.). Probably based on the 1966 and 1978-79 reports, Johnsgard (2013) stated that Lesser Scaup is “Known to have nested at Crescent Lake NWR but not at Valentine NWR.”

Abbreviations

NWR: National Wildlife Refuge
SL: Sewage Lagoons
WPA: Waterfowl Production Area (Federal)
UNSM: University of Nebraska State Museum

Acknowledgement

Photograph (top) of a Lesser Scaup at Fontenelle Forest, Sarpy Co, on 22 Mar 2011 by Phil Swanson.

Literature Cited

Ducey, J.E. 1988. Nebraska birds, breeding status and distribution. Simmons-Boardman Books, Omaha, Nebraska, USA.

Johnsgard, P.A. 2013. The Birds of Nebraska, Revised Edition 2013.  Zea E-Books, Book 17

Jorgensen, J.G. 2012.  Birds of the Rainwater Basin, Nebraska.  Nebraska Game and Parks Commission, Lincoln, Nebraska, USA.

Rosche, R.C. 1994. Birds of the Lake McConaughy area and the North Platte River valley, Nebraska.  Published by the author, Chadron, Nebraska, USA.

Tallman, D.A., Swanson, D.L., and J.S. Palmer. 2002. Birds of South Dakota. Midstates/Quality Quick Print, Aberdeen, South Dakota, USA.

Recommended Citation

Silcock, W.R., and J.G. Jorgensen.  2020.  Lesser Scaup (Aythya affinis), Version 1.0. In Birds of Nebraska — Online. www.BirdsofNebraska.org

Birds of Nebraska – Online