Wild Turkey on the Rocks?
The reintroduction of America's beloved holiday fowl has been one of conservation's great triumphs--but now some populations are plummeting. What's going on?
Researchers are taking a two-pronged approach to studying wild turkey populations. First, partners in the Southeast Wild Turkey Reproductive Decline Study are poring through mountains of data to tease out possible factors that might be dampening turkey tallies across the region. "It's very clear that something is going on," says Chamberlain, who is leading the study. So far the declines are occurring across habitat types, from heavily forested mountain regions to pine flats and coastal plain swamps. "Almost assuredly," Chamberlain says, "it will be a combination of factors at work."
A host of potential problems are under discussion. Some of the hardest-hit states, such as Arkansas, have endured a succession of cool, wet springs, which fuels concern about the "wet hen hypothesis." Damp air and soggy feathers create ideal scenting conditions for predators, which might then find nesting hens more easily. Many biologists point to an increase in mid-sized predators such as raccoons in the wake of the collapse of the trapping industry. The relatively recent arrival of a new predator, the coyote, to parts of the South has raised a flag. So, too, has the expansion of fire ants and feral hogs. No one knows just how much of an impact, if any, these things might have on wild turkey populations.
Some theorize that the declines may not be as bad as feared; decreasing population numbers could be a natural response to the reintroductions. In other words, in many areas, wild turkey numbers may have reached an equilibrium after years of rapid growth. "With restoration," Chamberlain explains, "so many birds exploited these vacant niches that populations simply took off." Certain landscapes may be at their full carrying capacity--there's only so much food, nesting cover, and brood habitat available. "Turkey restoration is a relatively new phenomenon," explains Jason Isabelle, a wild turkey biologist for the Missouri Department of Conservation. "Our population peaked early in the last decade, and we suspect that the numbers we're looking at now are more sustainable."
Biologists agree that both habitat quantity and quality has changed across the South, and not in a good way for wildlife. Between 2000 and 2010, the region's human population grew faster than in any other part of the country. In the first part of that decade logging was rampant. Habitat loss will likely continue, and an erosion of habitat quality on large forest tracts could lead to bird declines. At the same time, forest ownership has changed dramatically. Between 2000 and 2005 alone, more than 18 million acres of southern industrial timberlands were sold, largely to timber investment management organizations that worry less about sustainability and more about financial returns. "This may be a big part of the problem," says Hughes. "Timber companies that used to do good, active management--lots of fire, patchy thinnings--are going by the wayside. That activity created nesting and brooding cover."
While the study team is crunching numbers from across the Southeast, turkey researchers are turning to emerging technology that promises a far higher-resolution picture of wild turkey populations than ever before available. In one recently completed Georgia study, researchers hiked through longleaf pine stands at night using handheld thermal imaging scopes to identify specific roosting trees used by wild turkeys, then returned in daylight to take exact measurements of what wild turkeys look for in an overnight roost. The work could lead to better management guidelines for landowners.
In Louisiana and Texas researchers are using small 4-inch-by-2-inch GPS units to study how wild turkeys respond to flooding and hunter pressure. Chamberlain is heading up a new project in Georgia to study how nesting wild turkeys respond to prescribed fire. His students hope to capture and outfit at least 30 birds with GPS units, and follow them throughout the breeding and nesting seasons. Data from the GPS units can be downloaded from as far away as a mile, giving researchers a detailed look at where the birds go when their nesting areas are burned, how far they travel, and how long it takes them to return. "In this part of the world, up to half of the landscape is burned in any given year," Chamberlain says. "We've never been able to get at how birds respond to the timing and scale of fire, but now we can. It's actually quite an exciting time to be thinking about turkeys. In the next one to five years we'll see a massive increase in the amount of information we have about these birds."
Studying the status of wild turkeys can suggest how other animals are faring in a variety of habitats. While they need wooded landscapes, wild turkeys can make a living in a wide variety of habitats, from open hardwoods to managed pine plantations to tangled bottomland swamps. In the spring, however, they are less flexible. Hens and young turkeys in particular shift from being a forest bird to an early successional habitat species: To survive, poults need insect-rich grasses and shrubs and relatively open cover in which to chase their dinner. It's the same habitat that supports a host of other birds facing population declines, from bobwhite quail to dickcissels to bobolinks.