Turkeys survived colonization and near extinction. Now they're declining again, puzzling scientists

When scouting the state for wild turkeys to include in data collection, researchers found one nest right next to a rail road track in the middle of a 10-yard stretch of the road’s median, said Nicolle De Filippo, a PhD student at Ohio State University studying turkey disappearances.

“Surprisingly, she hatched one bird,” De Filippo told Salon in a phone interview. “It didn't survive very long, but it just shows their resilience — that even when they're nesting in something that is terrible, such as the side of the road next to a train, they can make it happen.”

Although most of the turkeys taking center stage on Thanksgiving dinner tables this week probably come from farms, turkeys do roam wild in many U.S. states. Considered one of the country’s greatest conservation success stories, wild turkeys made a comeback after facing near-extinction in the 20th century. But in the past decade or so, turkey populations have again declined in some regions, and scientists studying this phenomenon are unsure why.

“It's probably not one specific cause, and there's not going to be a silver bullet that's driving turkey population decline,” said Dan Kaminski, a wildlife research biologist with the Iowa Department of Natural Resources studying turkeys. “It's probably a combination of factors.”

As colonists landed in North America in the 1600s, they destroyed huge swaths of the native turkey’s forest habitat to make room for agriculture and nearly hunted the bird into extinction. By the 1930s, it’s estimated that fewer than 30,000 turkeys survived — which is roughly how many polar bears exist today.

Turkeys weren’t the only animals pushed to the brink of extinction through colonization, and sharp decreases in bison, prairie dogs, and passenger pigeon populations led the government to pass a series of some of the first conservation laws designed to protect them. While the damage was done for species like bison, which were often exterminated to starve Indigenous people, these laws helped wild turkeys bounce back across the country. By 2004, the wild population had ballooned to 7 million.

While turkey populations continue to bloom in some parts of the country like parts of the West and Northeast, their populations have declined in eight states across the South and Midwest within the last decade. One 2023 study published in Ecology & Evolution estimates that the population of one species of turkey (Meleagris gallopavo silvestris) found in the East declined by roughly 9% annually over the past 50 years. In Kansas and Oklahoma, two of the states with the largest declines, turkey populations have decreased by 60% since 2007 and 51% between 2014 and 2019, respectively. 

“In some areas, wild turkeys are doing great and are even considered kind of a nuisance, with stories of people having to shush them out of their neighborhood, or getting into those human-wildlife conflicts,” De Filippo said. “But in our situation and in other states in the Southeast, we are actually seeing that nest success rate, or the ability of hens to successfully make babies, is suffering.”

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Scientists aren’t completely sure what is causing declining turkey populations, and determining a cause-and-effect relationship in ecology can be challenging. In Oklahoma, research suggests turkey populations could be declining due to an increase in the number of predators such as raccoons, possums or coyotes, feeding on their eggs or hens before they are able to mature, De Filippo said. 

“She’s really vulnerable when she is in that nest,” De Filippo said. “She is sitting on the ground for two weeks, so anything can come and flush her off and eat the eggs.”

Habitat loss is also probably contributing to declining populations. Turkeys like to nest in grasslands or open forests. However, the U.S. has lost over 80% of its grasslands in the past decade due to agriculture, urban development, and invasive species. In Iowa, 45% of grasslands have been lost since 1990, Kaminski said.

These losses affect many wild birds, and populations of several species that inhabit grasslands and open forests like turkeys have declined to a fraction of what their population once was. Prescribed burns in certain forests can help clear out forests to make them more suitable for turkey breeding and have been performed for this purpose by the U.S. Forest Service.

Turkeys have adapted and shown resiliency despite these habitat changes, Kaminski said. Like De Filippo, his research team often finds nests in odd places, with 10% of turkey nests in the state found in road ditches or patches of grass near waterways.

“These are not big, robust prairie fields — they are just little, narrow habitats that aren’t great for them,” Kaminski told Salon in a phone interview. “We have not seen a single successful nest out of a road ditch, but that is the available grassland habitat they are selecting.”

Other factors could be influencing the population as well, such as a massive decline in food sources like insects or disease outbreaks. Some states authorize people to hunt turkeys, but many that are experiencing declining populations have paused this practice until turkeys can be repopulated.

It could also be that turkey populations overshot their carrying capacity in the '80s and '90s and are now declining to a “new normal,” Kaminski said. 

Various research projects have been launched in Kansas, Iowa, Oklahoma and other states to try and better understand what’s behind declining turkey populations. Besides serving as a national cultural symbol, turkeys play an important role in the environment, dispersing seeds and helping to control invertebrate populations. They also serve as an important food source for large predators like bobcats in the Southeast.

Moreover, turkeys have had cultural significance for many tribes long before colonists threatened the bird the first time around. In Oklahoma, the Muskogee tribe has also launched turkey rehabilitation program to try and get these birds back.

Although climate change is expected to further reduce the habitats available for turkeys to breed, through these efforts, some states are seeing early signs that turkeys could once again s back. 

“After I left my master’s project and another student came in to finish out the grant, they had a successful hatch that actually made it to independence, which was something we hadn't seen in the last two years,” De Filippo said. “While it might not sound like the greatest number since it's only one brood surviving to independence, it's at least a little bit better than had been, and I think that little glimmer of hope helps.”