ST. LOUIS — Floaters and hikers of the Current and Jacks Fork rivers in the Ozarks of southeast Missouri may be lucky enough to see a small, sky-blue bird called the cerulean warbler. It has the dubious distinction of being the fastest disappearing member of the warbler family.
In the past four decades, the cerulean warbler's numbers have declined some 70 percent, which is why wildlife watchers are applauding the acquisition of an 80-acre plot of prime breeding ground for the warblers in the Ozarks.
While the plot seems tiny, its significance is much larger. The acreage is bordered on three sides by state and federal forest land, and the fourth side belongs to a conservation-minded private owner. The 80 acres, in essence, plugs the doughnut hole that, if cleared, would have allowed the intrusion of cowbirds and other predators that threaten many breeding warblers.
"Securing that tract and keeping it from being cleared and developed will enhance the reproductive success of pairs breeding within a mile around the site," said Jane Fitzgerald of the American Bird Conservancy, which announced the land acquisition this month.
Fitzgerald said that the largest numbers of cerulean warblers breed each summer in the ridges of the Appalachian Mountains in the eastern United States, making nests of grass and bark bound together with spider web. They then migrate to the eastern slopes of the Andes Mountains in northern South America to spend their winters.
And they're in trouble at both ends of their journey.
"In the Appalachians, they practice a type of coal mining in which the mountaintops are removed; they've taken some 100,000 acres of cerulean habitat and it's still going on," Fitzgerald said. "In South America, the birds winter on grounds of shade-grown coffee plantations. But there's a large conversion to sun coffee, which can be grown cheaper. You take out those overstory trees and lose the warbler habitat."
Most of the estimated 560,000 cerulean warblers breed in the eastern United States, with a smaller population using the bottomland forest along Ozark rivers. In May and June of 2007, counts were conducted in Missouri, Arkansas, Kentucky, Tennessee and Illinois. A total of 105 cerulean warblers were found, 74 in Missouri, 18 in Arkansas, nine in Kentucky and four in Tennessee. None were found in Illinois.
"Those are random counts," Fitzgerald said. "We know from our canoe surveys in the late 1990s and 2000 that there's probably a few thousand birds out there."
The American Bird Conservancy had bought 252 acres of wintering habitat in Colombia in South America, and was approached by a donor with $35,000 to spend in the United States. The conservancy contacted the Missouri Department of Conservation, which suggested the 80-acre tract between its 38,820-acre Angeline Conservation Area. Alley Spring, part of the Ozark National Scenic Riverways, is on a third side.
The Missouri Conservation Heritage Foundation committed $55,000 to the project, and The Nature Conservancy came up with the final $25,000 toward the total cost of $115,000 for the 80 acres. For now, the Conservancy is the official owner, but the tract most likely will be sold to the conservation department, and become public land.
In addition to being the kind of habitat preferred by nesting cerulean warblers, biologists assessing the property discovered a healthy population of rare tall larkspur growing along the banks of Horse Creek, which crosses the tract. The stately wildflower with purplish blue flowers is a popular nectar source for ruby-throated hummingbirds.