ST. LOUIS - Missouri officials and university researchers, worried the state's wild turkey population is on the edge of calamity, are embarking on an extensive study of the fowl, even preparing to track the birds with GPS "backpacks."
Missouri turkeys were once a species on the rebound. But over the last several years scientists have seen signs of a pronounced decline: They're counting fewer young turkeys in the state's forests and fields. And that tally, nosediving toward record lows, is falling faster than experts predict, sagging inexplicably short of official forecasts that had proven reliable for decades.
"Only in the last five to seven years have we seen this problem," said Mitch Weegman, one of the University of Missouri professors conducting the study. "We really don't know why."
Turkey numbers appear to be crashing in other states, too - Illinois, South Carolina and New York, for instance. But Missouri was on the front end of widespread turkey restoration efforts in the middle of the 20th century, which makes conservationists here keenly interested in this decline. And the state has an outsized population of turkey hunters, state officials said: More than 133,000 hunted in this spring's turkey season, harvesting 41,000 birds.
"The turkey hunting culture in Missouri is monstrous compared to other states," said Weegman. "There's a massive number of people concerned about these birds."
There are too many turkeys in Missouri to count individually. Instead, the state relies on staff, hunters and volunteers to calculate another key indicator: the number of young turkeys - called poults - seen with each mother hen in the field. The state then uses those ratios to forecast turkey breeding success each year, plan hunting season and guide wildlife management.
Missouri's highest statewide poult-to-hen ratio, at least since the species' rebound, was observed in 1971, when each hen had an average of 4.6 poults. By the late 1980s, though, a long-term decline had begun. 1987 was the last year when the state saw more than three poults per hen, and 2001 was the last time the numbers exceeded two. In 2016, poult ratios reached their lowest level in 56 years - less than one per hen - and have remained near record lows since.
Also troubling, the state's breeding forecasts have failed to accurately predict the extent of the collapse. Even in recent years, when conditions seemed favorable, turkey brood sizes were not as strong as expected.
Reina Tyl, a resource scientist with the Missouri Department of Conservation, called the recent numbers "mind-boggling."
"There's something going on here that we're not understanding and that we're not accounting for," said Tyl, who is also a board member for the state chapter of the National Wild Turkey Federation.
The department of conservation, which issued the $1.3 million grant, will assist the university's research.
"It's something the agency understands is a problem," said Tyl. "We're willing to invest a decent amount of money to find out what's going on."
The team begins this month testing strategies for attaching the monitoring devices to captive turkeys. One technique will glue small, one-gram devices to poults, so as not to interfere with their growth or development. Another will stitch the devices on.
Larger "backpack" versions will strap around the wings of adult turkeys.
Researchers will also set up weather stations and wildlife cameras.
Together, the stations, cameras and backpacks will allow researchers to cross-reference turkey locations with weather events, temperature and common turkey predators.
Weegman said researchers are considering multiple factors in the crashing poult counts.
Extreme rain or cold may affect their survival.
Some predators may have gained subtle advantages recently - there's evidence, for example, that adult turkeys smell more pungent when wet, meaning that increases in rainfall could make them more easily detected by predators.
Even a drop in the price of raccoon pelts since the 1980s could play a role. With fewer racoons getting trapped, more might be free to raid turkey nests.
But the culprit may also be harder to detect by weather station or wildlife camera: Turkey habitat may be getting crowded out.
In northern Missouri, for instance, more land is being farmed, thanks partly to changes that made marginal areas more profitable. In the Ozarks, meanwhile, the decline of local logging activity has allowed forests to mature and choke out brushy undergrowth that provides turkeys with shelter and camouflage.
Fieldwork is set to start in January and continue for several years on public and private land near Lancaster, in northern Missouri.
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