Author’s Note: Be sure to catch up with A Brief History of the Golden-winged Warbler Part I, here.

The Golden-winged Warbler was seemingly never common in Ohio. It had been variously described as a "transitory visitor" by Jared Kirtland in 1838; a "rare summer resident" by John Wheaton in 1879; and "irregular in distribution" by William Dawson in 1903.

By the early 1800s, the First Industrial Revolution was ramping up, and deforestation in the North American landscape was accelerating. Massive tracts of ancient forest habitat that separated these species were felled, first via selective thinning, then later via clearcutting, feeding iron furnaces and providing raw material for furniture, fences, homes, hearths, and railroads. Cleared forests were turned into farms, and areas unsuitable for farming were left raw and denuded.

In 1830, the Erie Canal opened a route between the Hudson River and Lake Erie, giving large, mechanized farms in western New York, Ohio and Indiana a competitive advantage over those further east. This encouraged farmers to abandon their smaller, rockier New England farms in favor of more arable properties to the west². This deforestation, farm abandonment, and subsequent westward migration of settlers would continue over the next century. Harlan reported in The Birds of Ohio - 150 Years Later (1988)³ that precipitous population declines of several iconic species occurred between 1820 and 1870: the Passenger Pigeon (Ectopistes migratorius), Carolina Parakeet (Conuropsis carolinensis), and Greater Prairie Chicken (Tympanuchus cupido). By 1875, most of the original old growth forests were gone from Ohio, wetlands had been drained, and prairie habitat had been plowed and converted into farmland.

Around the turn of the century, successional habitat had begun to regenerate in the formerly farmed or forested landscapes – prime habitat for the Blue-winged & Golden-winged Warbler. It is not surprising that the first hybrids appear in the 1870s. The Golden-wings would arrive first, followed shortly by the Blue-wing. The latter, with its broader habitat preferences, was able to continue using the habitat after the Golden-wings no longer found it suitable; although they too would be pushed out as the trees aged. Without maintenance, early successional forests turn into woodland within 25 years or so, meaning this prime habitat was relatively short-lived.

This is the pattern throughout their ranges: the forests were cleared for the Industrial Revolution and the land was farmed for a century or so, then abandoned; as the forests began to grow back, first the Golden-wings moved in, followed by Blue-wings within 10-15 years. As the trees mature, the Goldens shift their range to the north and/or are absorbed into the Blue-wing population via hybridization. Once the Blue-wing arrives in Golden-wing territory, replacement of the Golden-wing by the Blue-wing occurs within 50 years¹.

A copy of Birds of the Toledo Area is at the Ohio History Center Archives & Library, its record is here.

By the mid-20^th century it is concluded that human-caused habitat disturbance – i.e. the widespread deforestation and farm abandonment that took place in the 19^th century – is likely at least one of the drivers behind hybridization. Ernst Mayr, one of the most well-known and prolific natural history authors of the 20^th century, wrote of the species in 1942 in Systematics and the Origin of Species⁸: “it is probable that the hybridization is of recent date and caused by manmade habitat disturbances.”

But there was more to the story than the Blue-wing hybridizing them out of existence. Lou Campbell documented a dramatic decline of the Golden-winged Warbler between the 1930 and 1945 in Oak Openings, their last stronghold in the state. In his 1968 book Birds of the Toledo Area⁸, he reported 37 singing males in 1932; an average of 14 singing males from 1937-39; and 10 in 1945. From 1950 to the printing of the book in 1967, only 1 – 3 were seen each summer. He states, “Drainage, clearing of land for farming and home building, insect controls, and perhaps the loss of wilderness atmosphere have all combined to cause this decline.”

No breeding records for the Golden-winged Warbler have been reported in Ohio since the 1930s. All sightings since the 1980s have been of lone singing males in Oak Openings, Cuyahoga National Park, Glen Helen Preserve, and Lake Hope State Park. There were also no confirmed breeding records during the First (1982–1987) or the Second (2006–2011) Atlas of Breeding Birds in Ohio⁹. The most recent summer record occurred on June 2, 2023 in Columbiana County, Ohio – although there was no evidence of breeding, and many singing Blue-winged Warblers were present (see the record here: https://ebird.org/checklist/S140278759). The Blue-winged Warbler, having been reported in 80 of Ohio’s 88 counties by 1935⁹, also experienced a significant range contraction during the latter half of the 20^th century. Significantly fewer records were reported in the glaciated portion of the state during the Second Atlas as compared with the First Atlas¹⁰.

A copy of The second atlas of breeding birds in Ohio is at the Ohio History Center Archives & Library, its record is here.

It appears separation between these two species is now no longer possible. Brought into contact by human-caused disturbance, the future of the imperiled Golden-winged Warbler is now uncertain. Early successional habitat is now extremely scarce in Ohio, and indeed in much of the Eastern United States. Marshes, wetlands, bogs, and the otherwise shrubby, wet habitats favored by the Golden-wing (and many other species!) have long since been drained, tiled, and turned into agriculture. Early successional habitats also suffer from a PR problem: the tall flowering forbs, swaying grasses, and dense shrubby growth that characterize them are viewed as unaesthetic, something to be mowed into homogeneity. But early successional forests are not only important breeding habitat for the Golden-winged Warbler; these structurally complex habitats with ample food sources and cover are also heavily used by other songbird species during fall migration¹¹.

The future of the Golden-winged Warbler is uncertain. If management of early successional habitats is not prioritized, the Golden-winged Warbler may be driven to extinction in the relatively near future throughout its range – both by a lack of breeding habitat, and by genetic swamping by its close relative, the Blue-winged Warbler. However, if sufficient efforts are made to restore and maintain these once-scarce habitats, it may be possible to hear the raspy buzz of the Golden-winged Warbler in Ohio once again.

References

[1] Gill, Frank B. 1980. "Historical aspects of hybridization between Blue-winged and Golden-winged warblers." The Auk 97.1: 1-18. https://sora.unm.edu/sites/default/files/journals/auk/v097n01/p0001-p0018.pdf

[2] Kingsley, N. P. 1974. The timber resources of southern New England. USDA Forest Service Resource Bulletin NE-36. https://archive.org/details/timberresourceso36king

[3] Streby, H. M., D. E. Andersen, and D. A. Buehler. 2016. Golden-winged warbler ecology, conservation, and habitat management. Studies in Avian Biology, Cooper Ornithological Society, CRC Press/ Taylor & Francis. ISB no. 13:978-1-4822-4068-9. https://conservancy.umn.edu/items/d4dca0dc-7c66-4682-ab06-25ba0192c2d4

[4] Harlan, Robert. 1988. The Birds of Ohio - 150 Years Later. Ohio Cardinal: Vol. 11:3, Article 1. https://digitalcommons.usf.edu/ohio_cardinal/vol11/iss3/1

[5] Hicks, Lawrence E. 1929. Some Interesting Ohio Records. Wilson Bulletin: Vol. 41:1, 43-44. https://www.jstor.org/stable/4155716?seq=1

[6] Hicks, Lawrence E. 1933. The Breeding Birds of Ashtabula County, Ohio. The Wilson Bulletin, 45(4), 168–195. http://www.jstor.org/stable/4156234

[7] Hicks, Lawrence E. 1935. Distribution of the breeding birds of Ohio. Columbus, Ohio: Ohio State University Press. https://babel.hathitrust.org/cgi/pt?id=mdp.39015068570509

[8] Campbell, Louis W. 1968. Birds of the Toledo Area. The Blade.

[9] Mayr, Ernst. 1942. Systematics And The Origin Of Species. Columbia University Press, New York, p. 262. https://archive.org/details/in.ernet.dli.2015.20284/page/n277/mode/2up

[10] Rodewald, P. G., Shumar, M. B., Boone, A. T., Slager, D. L., & McCormac, J. 2016. The second atlas of breeding birds in Ohio. The Pennsylvania State University Press.

[11] Cashion, Erin. 2011. Avian use of riparian habitats and the conservation reserve program: migratory stopover in agroecosystems. MS thesis. The Ohio State University. https://etd.ohiolink.edu/acprod/odb_etd/ws/send_file/send?accession=osu1307904873&disposition=inline