Wild Turkey Chicks and Post-Flight ReindeerFeasts

While our traditional Thanksgiving turkey feasts aren’t in danger of disappearing, wild turkeys could be. Soon, climate change could affect the success rates of wild turkey chicks, like this one.

Every year, without fail, Thanksgiving and Christmas seem to come right on top of each other. The four weeks between the two holidays fly by, with hardly enough time to savor one before the other is upon us. Magical, flying reindeer, in other words, quickly follow the turkey feast.

But while those traditional turkey meals (most Thanksgiving turkeys come from a farm, raised specifically for meat) aren’t in danger of disappearing anytime soon, wild turkeys may be facing a difficult future. A new study finds that while precipitation levels during nesting season are not related to reproductive success for wild turkeys—which runs counter to the conventional wisdom regarding the role that rainfall plays—climate change could soon affect wild turkey populations in a negative way.

Another new study suggests that it’s not Rudolph’s red nose that helps reindeer (also known as “caribou”) find food during snowy Arctic winters, but instead a unique adaptation of their eyes to their favorite food. Reindeer may have developed their unique ability to see in the ultraviolet (UV) spectrum so they can more easily spot their primary food, the algae-fungi fusion known as lichens—which absorb UV—in the winter landscape. This finding helps explain the long-standing scientific mystery as to why reindeer—including Rudolph and her fellow airborne ungulates from the classic story—have UV vision.

Wild turkeys are tolerant of a wide range of conditions. They live year-round in forests with interspersed clearings in 49 states (excluding Alaska), and in parts of Canada and Mexico. Some describe the ideal turkey habitat as one-half wooded, one-quarter abandoned fields and one-quarter active agriculture.

Overturning conventional, wild turkey wisdom about nesting survival

Wild turkeys are tolerant of a wide range of conditions, but there are a host of factors that can affect their reproductive success. So, researchers from North Carolina State University recently focused on two of those conditions: precipitation and temperature, and how they may influence nest survival during the incubation period.

For the study, scientists focused on daily nest survival, which is whether the eggs in the nest survive any given 24-hour period. Over the course of eight years, researchers monitored 715 turkey nests and collected daily precipitation and temperature data for each nest during the entire incubation period. For temperatures, the extent to which they varied from historical averages at each nest site was examined. This data was then analyzed to determine how precipitation and temperature were associated with daily nest survival.

What was most surprising, state the scientists, who published their findings in The Journal of Wildlife Management in February 2024, was that precipitation during nesting was not a good predictor of daily nest survival. Previously, it was widely believed that particularly rainy weather made it more likely that eggs wouldn’t survive. The researchers also found that temperatures which were higher than historical averages were associated with higher rates of daily nest survival during incubation. Since peak nesting season is generally in April, that relates to warmer-than-average spring weather.

Researchers recently conducted studies to determine how the weather is influencing turkey nesting success right now. They found that higher temperatures in January are associated with worsening survival rates of chicks (also known as “poults”).

Taken by itself, this might suggest that climate change could benefit turkey reproductive success and, by extension, turkey populations. However, the scientists also looked at precipitation and temperature data for the months leading up to nesting season and at the overall likelihood that a turkey nest will successfully hatch at least one egg. And when looking at both of those datasets, writes the North Carolina State University team, things get a lot less clear.

For example, the data suggest that more precipitation in January—long before nesting season—is associated with greater nest survival. The facts also show that higher temperatures in January are associated with worse nesting survival. But there is so much uncertainty related to those findings that it’s not clear whether there’s a real relationship there, or if it’s an anomaly. However, it does temper any enthusiasm we might have about the likelihood that climate change will benefit turkey populations, conclude the study’s authors.

Discovering how reindeer can feast during dark and snowy winters

When Santa’s exhausted reindeer finally set down their sleigh in the deep snow of the North Pole early Christmas morning, it’s not Rudolph’s radiant, red nose that will help them find sustenance in the barren landscape.

Reindeer are cool animals—in more ways than one. These northern-clime residents have an extraordinary visual system, which is fascinating not only at Christmastime but all year round.

Instead, in a new study published in the science journal i-Perception, researchers from Dartmouth College in New Hampshire and the University of St. Andrews in Scotland report that it’s the eyes of Rudolph and her reindeer sisters that will help them spot their favorite food during dark and snowy Arctic winters.

The findings help explain the long-standing scientific mystery as to why reindeer can see light in the ultraviolet spectrum—and add intrigue to the smiling, airborne ungulates popularized in the classic story by 1926 Dartmouth graduate Robert L. May.

Reindeer subsist primarily on reindeer moss, or Cladonia rangiferina, which isn’t a moss but actually a species of algae-fungi fusion known as lichen. C. rangiferina forms thick, crunchy carpets across northern latitudes and is so integral to the survival of reindeer that even its formal name stems from the scientific term for reindeer: Rangifer.

Reindeer lichen (also known as “caribou moss,” “deer moss” and “reindeer moss”) is a lichen formed through a relationship between algae and fungi. It grows in both cold and hot climates in well-drained, open environments. As the common names suggest, it’s an important food for caribou.

The researchers worked in the Cairngorms mountain range in the Scottish Highlands, which host Britain’s only reindeer herd—reintroduced from Scandinavia after being hunted to extinction locally—and more than 1,500 species of lichen. Despite these options, reindeer in the Cairngorms rely on C. rangiferina during the winter. That’s a peculiar trait, say the scientists, because it’s unusual for any animal to depend so heavily on lichens, let alone such a large mammal.

To the human eye, the white lichen is invisible against the snowy backdrop of an Arctic winter. But the Dartmouth and University of St. Andrews researchers discovered that C. rangiferina and a few other lichen species that supplement the reindeer diet absorb UV light. Spectral data from the lichen and light filters calibrated to mimic reindeer vision revealed that these organisms appear to reindeer as dark patches against an otherwise brilliant landscape, making them easier to locate.

Providing a visual approximation of how reindeer might see the world is something other studies haven’t done before. The researchers say that if you could put yourself in their hooves and look at a white landscape, you’d want a direct route to your food rather than wasting energy wandering around searching for it in a cold, barren environment. If the reindeer can see lichens from a distance, that gives them a big advantage, letting them conserve precious calories at a time when food is scarce.

Given the importance of lichens in the reindeer diet, it’s possible that the animals’ eyes are optimized to single out this food staple at the time of year when it would be most difficult to find.

Previous research has shown that reindeer eyes change between summer and winter. Their tapetum—the light-enhancing membrane that gives many animals “shiny” eyes—transitions in winter from the golden color most animals have to a vivid blue that is thought to amplify the low light of a polar winter.

If the color of the light in the environment is primarily blue, then it makes sense for the eye to enhance that color to make sure a reindeer’s photoreceptors are maximizing those wavelengths. But the blue tapetum also lets up to 60% of ultraviolet light pass through to the eye’s color sensors. That means that reindeer see the winter world as a shade of purple, similar to how a person would see a room with a black light: UV-reflecting surfaces, such as snow, shine brightly; while UV-absorbing surfaces are starkly dark.

The researchers recount how scientists have sought to answer why the eyes of an Arctic animal that is active during the day would be receptive to the UV light that would be reflecting off every snow-covered surface. But their study suggests that the answer is tied to what UV light doesn’t reflect from: C. rangiferina and other bushy lichens.

Here’s to many more Thanksgivings—and wild turkey chicks—in the future; and countless, reindeer-powered, Christmastime flights to come.

Given the importance of lichens in the reindeer diet, it’s possible that the animal’s eyes are optimized to single out this food staple at the time of year it would be most difficult to find. So, while the luminescent nose of the most famous reindeer of all “may light the way for Santa to see by,” the researchers write, “it is Rudolph’s blue eyes that allow her to find dinner after a long Christmas season.”