From 1975 to 1979, Paul Hamel and colleagues spent 7,000 hours walking through the Francis Marion National Forest and adjacent lands in South Carolina, playing the song of the Bachman’s Warbler and listening for the response that never came.
“Eventually, my adviser said ‘this is a biology department, not a history department!’ So I expanded the study to look at other warbler species and their habitat,” says Hamel, who is now an emeritus research wildlife biologist at the USDA Forest Service Center for Bottomland Hardwoods Research.
Hamel joined the FS in 1993 and is a renowned ornithologist, an expert in the Cerulean Warbler.
He wrote Bachman’s Warbler: A Species in Peril, the second edition of which is now available as a free electronic book, re-published by the Southern Research Station. “The opportunity to place this otherwise-out-of-print book online for future scholars was too good to overlook,” says Hamel.
Most likely, every Bachman’s Warbler has died, and the species is beyond our comprehension. However, traces of the bird’s existence remain. Museums maintain collections of specimens that are invaluable and irreplaceable. And libraries archive field notes, correspondence, and other primary materials.
Hamel used such material, along with scholarly works and his own research, to discuss what is known of the bird’s habits and habitat. He also discusses its distribution and potential causes of decline.
A second part of the book includes a bibliography, which lists 504 publications that mention Bachman’s Warblers. The new edition also includes high quality standardized photos of 308 museum specimens and the measurements of their bodies. All of the specimens were collected between 1832 and 1949.
“After the discovery of the birds in 1832 and 1833, more than 50 years passed before any were found again in the U.S.,” says Hamel. “’Rediscovery’ is a popular word in this context.”
Bachman’s Warbler was probably never a common species. By 1973, it was listed as endangered. The last indisputable sighting was in 1962, near what is now the Cape Romain National Wildlife Refuge in South Carolina.
Many warbler species are Neotropical migrants, which means they spend the summer in North America and overwinter in Central or South America. In the winter, the Bachman’s Warbler has only been documented in Cuba, suggesting a restricted winter range. Perhaps it once lived in other Caribbean habitats. In the U.S., it spent summers in the Atlantic and Gulf Coastal plains and inland along the floodplains of major rivers.
Bachman’s Warblers were aggressive toward their own and sometimes other species, and the males’ song was described as a buzzy trill of “zeep” notes. The birds built nests in shrubs and may have relied on canebrakes for habitat. Canebrakes once lined riverbanks throughout the Southeast but were usually one of the first lands cleared for farming when European settlers arrived.
In the Mississippi Alluvial Valley, some evidence suggests the birds nested in the higher and drier parts of the swamps – areas that would have been more accessible and thus logged sooner than other parts of the swamps. In these lands, logging through the late 1800s may have created ideal habitat, although it did not last. As more land was cleared and more streams were channelized, immense tracts of habitat were eradicated. Similarly, the bird’s winter habitat in Cuba has been converted to at least 85 percent agriculture, urban, or suburban.
But the bird disappeared so long ago that many unknowns remain.
“To what extent did the Bachman’s warbler – or its insect food supply – actually depend on old-growth forests and cane thickets?” says Hamel. “The entire species slipped away before such questions could ever be answered.”
Genetic analysis has recently revealed that golden-winged and blue-winged warblers are its closest relatives, as had been long suspected. Just like its close kin, the Bachman’s Warbler probably foraged for insects in leaves, clumps of dead leaves, and flowers. Unlike its closest relatives, Bachman’s Warbler had a distinctively curved beak. In Cuba, it may have sought nectar from Hibiscus tiliaceus flowers.
Information about the elusive bird is now freely available to managers, bird-watchers, scientists, and citizen scientists.
For more information, email Paul Hamel at email@example.com.