Wild turkeys struggle to shift their behavior in response to climate change

New research on the reproductive behavior of the eastern wild turkey suggests that these birds may not significantly adjust the timing of their nesting cycles in response to changing climate patterns. A lack of flexibility could put wild turkeys at risk as shifts in climate threaten the availability of food resources and protective vegetation, among other factors.

Chris Moorman, a professor in North Carolina State University’s Fisheries, Wildlife and Conservation Biology Program, underscored the implications of the findings. “There are implications here for turkey populations if individuals are inflexible in their ability to shift their reproductive activities, as resources are certainly going to change in the future.”

This inflexibility could result in what scientists refer to as “phenological mismatch,” which Professor Moorman described as the incongruity “where the timing of an animal’s natural history doesn’t match up with the food and cover resources that are critical for successful reproduction and survival.”

Past challenges for wild turkeys

Overhunting and habitat loss previously drove eastern wild turkeys to the brink of extinction, but the species has since rebounded and is now prevalent throughout North America. Nonetheless, a decline in the southeastern United States population since 2009 has prompted some concern. 

While North Carolina maintains a stable population, measured by hunting harvests, other southern states have introduced hunting restrictions in an effort to halt or reverse the decline. Researchers continue to explore the role of various factors, such as weather, climate change, and emerging diseases, on turkey populations.

The resilience of turkeys, however, has allowed the species to recover from past challenges. “Turkeys are a highly adaptable species; this adaptability facilitated their ability to be restored,” said study lead author Wesley Boone, a postdoctoral research scholar at NC State. 

Boone noted that they are conducting the research to understand if turkeys can persist in a future defined by a changing climate and altered landscapes.

How scientists conducted the study

To investigate the potential impact of climate change on turkey nesting, the researchers monitored the nesting patterns of eastern wild turkeys across five Southeastern states over a period of eight years. 

Employing GPS transmitters attached to captured female turkeys, the team could remotely track the birds’ movements, providing insights into when the turkeys began incubating their nests.

The study incorporated weather data spanning 2014 to 2021 to determine whether variables like temperature, rainfall, and the timing of “spring green-up” (the time when vegetation begins to grow in the spring) had any bearing on when turkeys started incubation. They also projected whether turkey nest timing would shift by 2041-2060 under two climate change scenarios.

What the researchers learned

Analyzing the data from 717 total nests and 186 “successful” nests that hatched at least one egg, the researchers found that temperature and rainfall were associated with only slight changes in nesting times. These changes were so minimal they could be measured in hours, not days.

Upon further analysis, the researchers discovered that climate change-related shifts in average precipitation and temperature changes could adjust the timing of successful nests by less than three hours. Surprisingly, they found no connection between turkey nest timing and spring green-up.

“We did find relationships between nest timing, rainfall, and temperature, but when we projected that into the future, there is no biological relevance in the shift in timing,” said Boone. Yet, he warned that this unresponsiveness to climate change could be problematic, as the crucial food and cover resources associated with spring green-up are likely to shift earlier in the future.

“We did not project drastic changes in the timing of when wild turkeys nest under climate change,” said Moorman. “Turkeys seem relatively inflexible as to when they reproduce – nesting is initiated around the same time each year with only slight shifts in the timing, regardless of weather conditions.”

Future studies on eastern wild turkeys

The research, published in the journal Climate Change Ecology, marks the first in a series of studies aiming to understand the impact of climate change on the reproduction of the eastern wild turkey. 

Future studies will explore how temperature and precipitation affect the survival of turkey nests and the recently hatched young, called poults. The implications of these studies could influence long-term conservation strategies for turkeys, including the scheduling of hunting seasons.

“There could be a lot of factors interacting to cause declines, including timing of the hunting season, land-use change that impacts habitat, changes in predator populations, as well as weather, climate and diseases,” said Boone. “We need to begin chipping away at the questions to build a comprehensive understanding of the current and future threats to wild turkey population sustainability.”

Eastern wild turkeys

The eastern wild turkey (Meleagris gallopavo silvestris) is a subspecies of wild turkey that is native to the eastern half of North America. This includes regions from northern Florida to Canada.

Physical characteristics

The eastern wild turkey is the largest subspecies of wild turkey, with males (also known as “toms” or “gobblers”) typically weighing between 18 to 30 pounds and females (hens) usually weighing between 8 to 12 pounds. 

Adult males also have a “beard,” which is a group of specialized feathers that protrude from the chest. This subspecies has dark metallic bronzing throughout its plumage, with a white-barred to chestnut-brown tail.

Habitat

Eastern wild turkeys can be found in a variety of habitats, including forests, swamps, and grasslands. They prefer hardwood and mixed conifer-hardwood forests with scattered openings such as pastures, fields, orchards, and seasonal marshes.

Diet

Turkeys are omnivores. They feed on a diverse diet of plant and animal matter, including seeds, leaves, berries, insects, and small vertebrates.

Behavior and reproduction

During the spring breeding season, males will display for females by puffing out their feathers, spreading their tails, and dragging their wings, also making a distinctive gobbling sound. Females then lay a clutch of 10-12 eggs, which they incubate for about 28 days.

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