Status: Uncommon regular spring migrant east, rare casual central, accidental west. Rare casual fall migrant east, accidental central and west.
Documentation: Specimen: UNSM ZM16966, 15 May 1993 Lincoln, Lancaster Co (Brogie 1997).
Taxonomy: No subspecies are recognized (Pyle 1997).
This species and Blue-winged Warbler V. cyanoptera hybridize frequently and produce fertile hybrids; their genomes are 99.97% identical, with plumage genes accounting for the difference (Toews et al 2016). Genetic studies indicate introgression of cyanoptera haplotypes into chrysoptera phenotypes with no reverse movement (Confer et al 2020), indicating that chrysoptera is being replaced by cyanoptera (Confer et al 2020). The only known phenotypically and genetically pure populations of chrysoptera breed in Manitoba, where numbers are increasing (Confer et al 2020), possibly even to the extent of increasing numbers being reported in Nebraska.
The hybrid form “Brewster’s Warbler,” more common than the recessive form “Lawrence’s Warbler”, has been reported five times in Nebraska: in Madison Co 18 May 2020 (Mark Brogie, pers. comm., photo), Keya Paha Co 19 May 1982 (Brogie and Mossman 1983), at Fontenelle Forest, Sarpy Co 6 Sep 2007, and at Oak Grove WMA, Seward Co 13 Sep 2008. Some of these may have been introgressants; one in a Sarpy Co yard 21 May 2020 was identified as an F2 backcross between a Brewster’s Warbler and a Golden-winged Warbler (Phil Swanson, pers. comm., photo). There are no Nebraska reports of “Lawrence’s Warbler”.
Hover mouse over photos below for captions.
Rather startling was a hybrid between a male Chestnut-sided Warbler and a Brewster’s Warbler found in Pennsylvania 7 May 2018, known as the “Burket Triple Hybrid”; it sang a Chestnut-sided Warbler song, as expected since DNA determined the genetic makeup and found that the male parent was a Chestnut-sided (Grove 2019).
Changes since 2000: There has been a noticeable increase in numbers of spring migrants coincident with increases in populations in the western portions of the species breeding range (Sauer et al 2017), especially Manitoba (Confer et al 2020).
Spring: May 2,3,4 <<<>>> May 24,25,25
There is an earlier report 25 Apr 1982 Douglas-Sarpy Cos and a later report 6 Jun 1992 Keith Co (Brown et al 1996).
There are few reports away from the east, the single Panhandle record a singing male in Dawes Co 23 May 1997. Other westerly reports are 11 May 1991 Keith Co (Rosche 1994), 15 May 1998 Clear Creek WMA, Garden Co, 17 May 1955 Keith Co, one photographed 17 May 2008 Lake Ogallala, Keith Co, and 6 Jun 1992 Keith Co (Brown et al 1996).
Most reports of this species are recent; there were no reports until one was reported in Adams Co 17 May 1954, and there were only about 30 reports through 1992. There has been a marked increase in numbers in recent years, beginning with a major incursion in 1993 when there were 14 reports involving 15 birds, most at Fontenelle Forest (Grzybowski 1993). Most years since, 5-15 have been reported; 2016 was a banner year, with reports of 29 individuals and 27 were reported in 2018, but these numbers were dwarfed by the 45 reported in spring 2020. These recent increases in numbers reflect a continuing increase in the breeding population in Manitoba, where it was “very rare” as a breeder in the 1950s (Confer et al 2020).
- High counts: 5 at Fontenelle Forest 14 May 2016, 5 there 12 May 2018, and 5 there 12 May 2019.
Fall: Aug 22, 23, 26 <<<>>> Sep 13, 13, 14
There is an earlier report 2 Aug 2001 Otoe Co (Falk 2002) and late records of one in a Bellevue, Sarpy Co yard 24 Sep 2019 and one photographed 26 Sep 2017 at Fontenelle Forest, Sarpy Co.
Fall reports are rare, with only 36 in all, four of these in 2016, two in 2018, and three in 2019. There is a tendency for fall migration routes to be further east than in spring (Confer et al 2020).
The only reports away from the Missouri River Valley are the single Panhandle record, 14 Sep 1997 in Sowbelly Canyon, Sioux Co, 2-3 Oct 2010 Enders Reservoir, Chase Co, and 7 Sep 1973 Thomas Co (Williams 1974). Northernmost in the Missouri River Valley are 6 Sep 2016, singles in both Knox and Cedar Cos, and 11 Sep 1995 Washington Co (Grzybowski 1996).
UNSM: University of Nebraska State Museum
WMA: Wildlife Management Area (State)
Photograph (top) of a Golden-winged Warbler at Fontenelle Forest, Sarpy Co 10 May 2011 by Phil Swanson.
Brogie, M.A. 1997. 1996 (Eighth) Report of the NOU Records Committee. NBR 65: 115-126.
Brogie, M.A., and M.J. Mossman. 1983. Spring and summer birds of the Niobrara Valley Preserve, Nebraska: An annotated checklist. NBR 51: 44-51.
Brown, C.R., M.B. Brown, P.A. Johnsgard, J. Kren, and W.C. Scharf. 1996. Birds of the Cedar Point Biological Station area, Keith and Garden Counties, Nebraska: Seasonal occurrence and breeding data. Transactions of the Nebraska Academy of Sciences 23: 91-108.
Confer, J.L., P. Hartman, and A. Roth. 2020. Golden-winged Warbler (Vermivora chrysoptera), version 1.0. In Birds of the World (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.gowwar.01.
Falk, L. 2002. Birds in Otoe County. Published by the author, Nebraska City, Nebraska, USA.
Grove, D.S. 2019. The Identification of the Burket Triple Hybrid- a Brewster’s/Chestnut-sided Warbler. Pennsylvania Birds 33: 223-225.
Grzybowski, J.A. 1993. Southern Great Plains Region. American Birds 47: 426-429.
Grzybowski, J.A. 1996. Southern Great Plains Region. Field Notes 50: 74-77.
Pyle, P. 1997. Identification Guide to North American Birds. Part I, Columbidae to Ploceidae. Slate Creek Press, Bolinas, California, 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.
Toews, D.P.L., S.A. Taylor, R. Vallender, A. Brelsford, B.G. Butcher, P.W. Messer, and I.J. Lovette. 2016. Plumage Genes and Little Else Distinguish the Genomes of Hybridizing Warblers. Current Biology 26: 2313-2318.
Williams, F. 1974. Southern Great Plains Region. American Birds 28: 70-76.
Silcock, W.R., and J.G. Jorgensen. 2020. Golden-winged Warbler (Vermivora chrysoptera), Version 1.0. In Birds of Nebraska — Online. www.BirdsofNebraska.org