Turkey Roller Coaster
After peak, populations more in balance with yearly fluctuations
Few will argue that the comeback of the wild turkey is one of North America’s greatest conservation stories.After numbers were thinned terribly entering the early 1900s by habitat destruction and unregulated hunting, wild turkey populations had again reached huntable levels by the 1950s in many states, thanks to programs initiated by wildlife agencies. Today, according to the National Wild Turkey Federation, turkey are hunted in 49 U.S. states, seven Canadian provinces and in portions of Mexico, where restoration efforts are just beginning.
In recent decades, however, population numbers have dwindled, off and on, in different areas across the continent.
But turkey biologists say the current numbers could be the natural response to reintroduction and a balance has been reached after decades of rapid growth.
“When we look at turkey populations around a good part of the country, at least throughout the range of the Eastern subspecies, in a lot of states, the turkey numbers are less than what they were shortly after the peak following restoration,” said Jason Isabelle, a turkey biologist with the Missouri Department of Conservation. “The general consensus among turkey biologists is maybe the numbers we are seeing now are probably more likely to be sustainable than the high numbers we saw when the populations peaked.”
The first research effort for wild turkey restoration was initiated by the Virginia Cooperative Wildlife Research Unit in 1935. Other agencies followed and soon projects were in place to determine breeding patterns, habitat needs and restoration plans.
In the beginning, restoration plans centered on releasing pen-raised birds. However, poor survival rates hampered efforts for nearly two decades. The invention of the cannon net allowed for the trapping and transfer of large flocks of birds, a huge step in the restoration process and leading to the huge numbers of birds that hunters have become accustomed to in recent decades.
"Turkey restoration is a relatively new phenomenon,” Isabelle said. "Our population peaked early in the last decade, and we suspect that the numbers we're looking at now are more sustainable."
Contributing issues include the erosion of both the quantity and quality of sustainable habitat for the wild turkey. In the South, for instance, human population rates have soared. Also, from 2000-2005, more than 18 million acres of southern timberlands were sold, largely to timber investment management groups, which are typically more concerned with financial returns than wildlife sustainability.
Each year’s turkey population is affected significantly by that spring’s nesting and hatching periods. Changes in weather patterns can dramatically affect a particular year’s brood.
“I think we’re still going to see some pretty wide fluctuations in numbers, not that they’re going to be stable by any means,” Isabelle said. “If we have two, three, four years of good production in a row, hunters will notice a pretty good increase in bird numbers.
“But if we have two, three, four years of poor hatches in a row, the numbers will obviously be dramatically down. So I guess it would be a roller coaster of sorts in the future, just depending on what kind of conditions and what kind of production we have in any given stretch of years.”
Biologists also theorize that an increase in mid-sized predators, such as raccoons in the wake of the collapse of the trapping industry, could have a negative effect on turkey numbers. Experts are also studying the impact, if any, the expansion of fire ants and feral hogs might have on wild turkey populations.
Plus, there simply are regions that are at their full capacity. There’s only so much food, nesting over and brood habitat available.
“Every population has its carrying capacity,” Isabelle said. “When bird numbers are really high, you’ve got competition for nest sites, competition for brooding, habitat … even competition for food. You’ve got more critters out there for predators to key on as well. You’ve got all these factors that eventually stop a population from expanding.
“I think that as the population really grew after restoration, there were a lot of areas that didn’t have any birds whatsoever and the habitat was really great and they really took off at highly productive rates. Then as those factors sort of constrained the population, we’ve been seeing those reproductive rates decline for decades, really, as that population has matured. Some of those factors are still going to come into play as we see numbers fluctuate in the future, too.”