BREWER’S BLACKBIRD

Euphagus cyanocephalus

Status:  Common regular spring and fall migrant west and central, uncommon east. Fairly common regular breeder west. Rare casual winter visitor from the North Platte and Platte River Valleys south.

Documentation:  Specimen: UNSM ZM7025, 20 Jun 1901 Indian Creek, Sioux Co.

Taxonomy:  No subspecies are recognized (Jaramillo and Burke 1999, Gill and Donsker 2017), although Pyle (1997) recognized three weakly-differentiated subspecies, minusculus of coastal Oregon and California, brewsteri, breeding from northwest Territories to northern Oregon and Wisconsin, wintering from California to Georgia, and cyanocephalus, breeding from Oregon to California east to southern Wyoming and northern New Mexico, wintering to California and south Texas.

If these subspecies are recognized, cyanocephalus is the Nebraska breeding subspecies, and both it and brewsteri migrate through the state.

Changes since 2000: Brewer’s Blackbird has expanded its breeding range southward in the Panhandle since 2007; for many years it bred only on or near the Pine Ridge. This expansion is probably related to expansion of the breeding populations in southeast Wyoming and northeast Colorado which adjoin the Nebraska border.

Spring:  Feb 15,16,17 <<<>>> Jun 6,7,7 (central, east), Mar 22,28 (Rosche 1994),31 <<<>>> summer (west)

As with other Nebraska “blackbird” species, migration begins in late Feb, and peak migration probably occurs in mid- to late Apr (Rosche 1994). Probable early migrants were two in a blackbird flock at Branched Oak Lake, Lancaster Co 12 Feb 2015; other early dates are 17 Feb 1935 Logan Co and 23 Feb 1985 Boone Co.  Generally, though, it has been noted this species does not usually occur in mixed flocks with other blackbird species (Rosche 1994, Jorgensen 2012).  In the east, it also appears attracted to recent grassland burns (Jorgensen 2012, see High Counts, below).  Away from the breeding range, migration ends by early May, when most birds are at breeding sites.

There are numerous reports in the east and central through the end of Jun; we believe that reports in the east from mid-May through Jun or later are most likely incorrect identifications.

Migrants arrive later in the Panhandle, in early Apr, although there are earlier reports 8 Mar 2015 in Dundy Co and 15 Mar 1965 Dawes Co, but peak counts in the east and west are on almost identical dates. High counts in the east are on burned grassland.

  • High counts:  
    • East:  1000, including 800 in one flock at a burned pasture, in the eastern Rainwater Basin 14 Apr 2001, 300 in Fillmore Co 27 Apr 2000 (Jorgensen 2012), and 300 on a burn at Ponca SP, Dixon Co 25 Apr 2014.
    • West:  “several hundred” in Scotts Bluff Co 27 Apr 1994, a mixed-gender flock of 200 near McCook, Red Willow Co 25 Apr 2009, and 55 at Wilsonville, Furnas Co 14 Mar 2004.

Summer: Traditionally, Brewer’s Blackbird bred mostly in Sioux Co, particularly on the grasslands in the Harrison area (Rosche 1982). A colony had been present about 10 miles east of Harrison for many years but had not been occupied for some 15 years until five pairs were there 11 May 2016; there were two nests with eggs 23 May (Wayne Mollhoff, personal communication). Mollhoff (2001, 2016) showed that breeding occurred throughout the Pine Ridge to Sheridan Co during both breeding bird atlas periods (1984-1989 and 2006-2011), but only in the second atlas period was breeding noted south of the North Platte River. There were breeding season reports 2006-2011 in Scotts Bluff, Banner, Kimball, and Morrill Cos; breeding was confirmed in Scotts Bluff and Morrill Cos. This expansion of range was not unexpected, as Brewer’s Blackbirds breed in northeast Colorado (CBAP 2016) and Wyoming (Faulkner 2010) just west of the Nebraska Panhandle and the southwest and tend to move breeding colonies periodically. Probably reflecting this range expansion in southwest Nebraska, BBS trend analysis show the species has increased 5.23% (95% C.I.; -2.34, 13.89) during 1966-2015 (Sauer et al 2017).

Brewer’s Blackbird has been a summer resident in the eastern Pine Ridge since at least 1993, when it was listed as a summer resident in Sheridan Co (Morris 1993, Cortelyou 1993). It was reported in Sheridan Co 4 Jun 1986 and 5-12 Jun 1992, two were near Gordon, Sheridan Co 5 Jun 2013, and five were seen 13 Jun 2016 in southwest Sheridan Co.

Reports south of the North Platte River Valley apparently began in Morrill Co in 1987, when young were seen by Rosche (Ducey 1988); a female was feeding an immature on the Bighorn Escarpment south of Redington, Morrill Co 25 Jun 1995, and this location has hosted at least one breeding colony since. In 1998, 15+ pairs were present, and an active nest and three females carrying nest material were noted 15-16 May 1998 (Wayne Mollhoff, personal communication).

There are breeding season reports in Scotts Bluff Co 30 Jun 1965, 30 Jun 1982, and 23 Jul 1983, but breeding activity was not noted until 2007-2008, when at least one pair established in unusual habitat on the north side of Scotts Bluff NM. The first confirmed breeding for the county was 22 Jun 2010, when the first record on the Murray Lake BBS route was provided by birds at five stops, including two instances of adults carrying food. At about the same time, an adult was carrying food at Wildcat Hills NC, Scotts Bluff Co 19 Jun 2010.

Breeding was confirmed in Banner Co during 2006-2011 and there were breeding season reports there during the same period (Mollhoff 2016). Breeding season reports near the southern Panhandle breeding range may be late migrants or merely “summer wanderers”, as suggested by Thompson and Ely (1992) to be the case in western Kansas. Such reports for Nebraska are 4 Jun 2000 and 18 Jun 2001 Crescent Lake NWR, Garden Co and 19 Jul 1982 at Valentine NWR, Cherry Co (Dave Potter, personal communication). Of interest are reports from a BBS route near Benkelman, Dundy Co 27 Jun 2007 of six birds, reports from Kimball Co near Bushnell 6 Jul 1995 and 18 Jun 2011. These areas are adjacent to the northeast Colorado plains breeding range and probably represent range expansion from there. Reports east of the expected summer range in 2018 were from Cheyenne Co, where five were found 2 Jul and 15 on 9 Jul, Garden Co, seven on 27 Jun, and Box Butte Co, four on 3 Jul.

There are no documented records of breeding elsewhere in Nebraska since the 1930s (see Comments). Reported occurrences of nesting in Hall, Johnson, and Lancaster Cos (Bennett 1969, 1972, 1973, 1975) are almost certainly misidentifications of Common Grackle; the Johnson Co report was of nesting in a conifer in a suburban yard, typical of Common Grackle. The 1974 Hall Co report (Bennett 1975) was based on birds seen “carrying food”; Johnsgard (1979) suggested that this report may have been of a Rusty Blackbird, although there is no evidence to suggest any species other than Common Grackle. There are about 65 undocumented Jun and Jul reports of Brewer’s Blackbird away from the Panhandle breeding range outlined above; most, including BBS data, are from the east and south and are highly questionable.

  • Breeding phenology:
    Eggs: 1 May-14 Jun
    Nest Building: 12 (Grzybowski 1993)-16 May
    Nestlings: 31 May-22 Jun
    Fledglings 13 Jun-8 Jul

Fall:  Aug 26,27,28 <<<>>> Nov 13,14,15 (north)

Migrants appear statewide in late Aug and early Sep, although there are early reports 28 Jul 1979 at Lake Ogallala, Keith Co (Brown and Brown 2001), 14 Aug 1994 at Axtell, Phelps Co, and 17 Aug 2012 in Sherman Co. Early flocks were the 200 in Scotts Bluff Co 8 Jul 2012 and a mixed-age flock of 45 present for “a few days” near Fort Robinson, Dawes Co 23 Jul 2018. This species may have been affected by the very dry conditions in the west in 2012; flocks were noted on early dates: “lots were under a pivot” in Morrill Co 30 Jun and 200 were in a mixed icterid flock in Scotts Bluff Co 8 Jul.

Peak movement probably occurs in early Oct, and most migrants leave the state by the end of Nov.

Migrants are not uncommon in the east during Oct; 200 were in Sarpy Co 15 Oct 2009, and in the same year there were eight other reports 12-31 Oct of up to 15 birds.

There are several reports, including CBC data, after mid-Nov and as late as early Jan, almost all from the south and east, but overwintering is less-than-annual (see Winter). A single immature male was documented near Gering, Scotts Bluff Co 15 Dec 2007 (Brogie 2008). Highest CBC counts were 283 at Lincoln in 1986, 206 at DeSoto NWR in 1989, and 180 at Hastings in 1976.

  • High counts:  2000-3000 near McCook, Red Willow Co 18 Oct 2004, 2000 on 2 Oct 1976 at Oshkosh, Garden Co (Rosche 1994), and 1000 near Mitchell, Scotts Bluff Co 3 Sep 2000.

Winter: There are few mid-winter (Jan through mid-Feb) reports; documented records are of as many as 23 wintering below Keystone Dam, Keith Co through at least 3 Feb 2001, similar flocks (one of 22 birds) in Lincoln Co 2 Jan 1927 and 21 Jan 1930 (Tout 1947), one remained until 10 Jan 1998 from a flock of 33 at Wolf Lake, Saunders Co, and a group of 30 was in Lancaster Co 12 Jan 2013.  There are mid-winter reports from the northeast 2 Jan 2005 Beaver Valley CBC, 10 Jan 1981 Boone Co, 11 Jan 1986 Boone Co, and 14 Jan 2002, 14 in a mixed-species flock in Boone Co.  There are westerly reports 7 Jan 1991 Scotts Bluff Co, 11 Jan 1946 Logan Co, and two on 15 Jan 1998 at Gering, Scotts Bluff Co. Blake and Ducey (1991) stated that “a few overwinter some years” in southeast Holt Co.

Some undocumented winter reports in the east may have been misidentified Rusty Blackbirds.

Comments:  The recent expansion of the breeding range in the southern Panhandle is not an unprecedented phenomenon; Brewer’s Blackbird expanded its range significantly eastward “from Minnesota” beginning around 1914 (Martin 2002), particularly in Minnesota and Wisconsin (Bent 1968), implying that breeding in Nebraska during that time was likely if birds had reached Minnesota by 1914. Indeed, Glandon and Glandon (1934) considered Brewer’s Blackbird a “very common summer resident” in Logan Co, and Trostler reported a nesting colony 2.5 miles east of Niobrara at a farmstead in Knox Co 19 Jul 1904 (undated handwritten note from Trostler to Bruner in NOU Archives, fide Wayne Mollhoff). Jorgensen (2012) considered the only acceptable breeding record for the eastern Rainwater Basin one from Tout (1902), who collected eggs 9 Jun 1896 near York that were identified as those of Brewer’s Blackbird. These reports suggest that Brewer’s Blackbird may have bred across much of Nebraska in the late 1800s and early 1900s.

Abbreviations

BBS: Breeding Bird Survey
CBAP: Colorado Bird Atlas Partnership
CBC: Christmas Bird Count
NC: Nature Center
NM: National Monument
NOU: Nebraska Ornithologists’ Union
NWR: National Wildlife Refuge
SP: State Park
UNSM: University of Nebraska State Museum

Acknowledgement

Photograph (top) of a Brewer’s Blackbird in Sowbelly Canyon, Sioux Co 16 May 2017 by Michael Willison.

Literature Cited

Bennett, E.V. 1969. 1968 Nebraska nesting survey. NBR 37: 39-46.

Bennett, E.V. 1972. 1971 Nebraska nesting survey. NBR 40: 9-15.

Bennett, E.V. 1973. 1972 Nebraska nesting survey. NBR 41: 3-9.

Bennett, E.V. 1975. 1974 Nebraska nesting survey. NBR 43: 13-19.

Bent, A.C. 1968. Life histories of North American Cardinals, Grosbeaks, Buntings, Towhees, Finches, Sparrows, and allies. Bulletin of the United States National Museum 237. Three Parts. Dover Publications Reprint 1968, New York, New York, USA.

Blake, L., and J. E. Ducey. 1991. Birds of the eastern Sandhills in Holt County, Nebraska. NBR 59: 103-132.

Brogie, M.A. 2008. 2007 (19th) Report of the NOU Records Committee. NBR 76: 111-119.

Brown, C.R., and M.B. Brown. 2001. Birds of the Cedar Point Biological Station. Occasional Papers of the Cedar Point Biological Station, No. 1.

Colorado Bird Atlas Partnership [CBAP]. 2016. The Second Colorado Breeding Bird Atlas online database. Colorado Bird Atlas Partnership, Denver, Colorado, USA.

Cortelyou, R.G. 1993. The Spring 1993 Occurrence Report. NBR 61: 94-136.

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

Faulkner, D.W. 2010. Birds of Wyoming. Roberts and Company, Greenwood Village, Colorado, USA.

Gill, F., and D. Donsker (Eds). 2017. IOC World Bird List (v 7.3), accessed 30 January 2018.

Glandon, E.W., and R. Glandon. 1934. Notes on some Logan County birds. NBR 2: 31-36.

Grzybowski, J.A. 1993. Southern Great Plains Region. American Birds 47: 426-429.

Jaramillo, A., and P. Burke. 1999. New World Blackbirds- The Icterids.  Princeton University Press, Princeton, New Jersey, USA.

Johnsgard, P.A. 1979. Birds of the Great Plains: breeding species and their distribution.  University of Nebraska Press, Lincoln, Nebraska, USA.

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

Martin, S.G. (2002). Brewer’s Blackbird (Euphagus cyanocephalus), version 2.0. In The Birds of North America (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, New York, USA.  https://doi.org/10.2173/bna.616.

Mollhoff, W.J. 2001. The Nebraska Breeding Bird Atlas 1984-1989. Nebraska Ornithologists’ Union Occasional Papers No. 7. Nebraska Game and Parks Commission, Lincoln, Nebraska, USA.

Mollhoff, W.J. 2016. The Second Nebraska Breeding Bird Atlas. Bull. Univ. Nebraska State Museum Vol 29. University of Nebraska State Museum, Lincoln, Nebraska, USA.

Morris, R. 1994. Fall 1993 Occurrence Report (July 1-December 31). NBR 62: 3-50.

Pyle, P. 1997. Identification Guide to North American Birds. Part I, Columbidae to Ploceidae. Slate Creek Press, Bolinas, California, USA.

Rosche, R.C. 1982. Birds of northwestern Nebraska and southwestern South Dakota, an annotated checklist. Cottonwood Press, Crawford, 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.

Sauer, J.R., D.K. Niven, J.E. Hines, D.J. Ziolkowski, Jr, K.L. Pardieck, J.E. Fallon, and W.A. Link. 2017.  The North American Breeding Bird Survey, Results and Analysis 1966 – 2015 (Nebraska).  Version 2.07. USGS Patuxent Wildlife Research Center, Laurel, Maryland, USA.

Thompson, M.C., and C.A. Ely. 1992. Birds in Kansas. Vol. 2. University of Kansas Museum Natural History Publications Educational Series No. 12, Lawrence, Kansas, USA.

Tout, W. 1902. Ten years without a gun. Proceedings of Nebraska Ornithologists’ Union 3: 42-45.

Tout, W. 1947. Lincoln County birds. Published by the author, North Platte, Nebraska, USA.

Recommended Citation

Silcock, W.R., and J.G. Jorgensen.  2018.  Brewer’s Blackbird (Euphagus cyanocephalus), Version 1.0. In Birds of Nebraska — Online. www.BirdsofNebraska.org


Birds of Nebraska – Online