The December issue of the Wildlife Society Bulletin is now available

January 2, 2024 by The Wildlife Society

The Wildlife Society Bulletin is a benefit of membership in The Wildlife Society. Published four times annually, it is one of the world’s leading scientific journals covering wildlife science, management and conservation, focusing on aspects of wildlife that can assist management and conservation.

Join today for access to the Wildlife Society Bulletin and all the other great benefits of TWS membership.

Silver-haired bats produce identifiable songs consisting of repeated ultrasonic signals. These patterned sounds appear to be unique to this species and can be used to differentiate it from other bats. In a study in the December issue of the Wildlife Society Bulletin, researchers found that the songs may be part of mating behavior.

The December issue of the Wildlife Society Bulletin is now available. Credit: The Wildlife Society

Other articles look at waterfowl hunting participation, prairie-chicken translocations, shading marine turtle nests and more.

Log in to read the December issue today.

New Year’s Eve fireworks aren’t for the birds

January 2, 2024 by The Wildlife Society

The use of fireworks on New Year’s Eve can cause a massive flight response in birds, researchers found. Using data from weather radar and bird counts, an international team of researchers working in the Netherlands found an average of 1,000 times as many birds are in the area near fireworks displays as on other night. In some cases, the numbers peak up to 100,000 times the normal number. The effects are strongest within 5 kilometers of fireworks, but even 10 kilometers away, birds in flight are ten times normal. That’s particularly concerning, researchers say, because of the widespread use of fireworks across the country to celebrate the New Year. The displays cause “a flight response in birds of unprecedented scale, with immediate and lasting energetic consequences,” researchers concluded.

Read the study in Frontiers in Ecology and the Environment.

JWM: Reducing harvest regulations can boost male turkey numbers

December 29, 2023 by David Frey

As wild turkey populations decline in the southeastern United States, reducing harvest could help keep more male turkeys on the landscape.

Biologists have debated the impact of hunting on wild turkeys. Are more turkeys killed because of hunting? Or would the birds that hunters take home have been killed by predators, anyway?

In a study in the Journal of Wildlife Management, researchers studying eastern wild turkeys (Meleagris gallopavo silvestris) in the Southeast found male turkey survival is 30% higher in nonhunted populations.

That’s good news for managers looking for ways to bolster males in the population, said lead author Patrick Wightman, a research scientist at the University of Georgia, although how much more males would impact overall turkey populations isn’t clear.

“From a management perspective, one of the big takeaways is, if you’re wanting to increase male survival, you can decrease harvest,” said Wightman, who led the study as a postdoctoral researcher at the university. He hopes future research can shed light on how tight those restrictions would need to be to have a meaningful impact.

Wightman and his colleagues studied 860 male turkeys—some banded and some fitted with transmitters—in Georgia, Louisiana, North Carolina and South Carolina from 2014 to 2022 and created models based on their survival. In hunted populations, adult males had about a 50-50 chance of surviving in a year, Wightman’s team found. Annual survival among nonhunted turkeys was about 30% higher. Predation played little role.

To increase male turkeys on the landscape—and increase hunter satisfaction in the long run—managers may want to test different restrictions, including season length and bag limits, the researchers concluded.

“The vast majority of hunters are conservationists,” Wightman said. “If state agencies are taking away opportunities—whether it’s bag limits or season dates—I think the general public in the hunting community would be more supportive if they knew it would have some impact on survival.”

How much impact that would have on overall wild turkey survival is unclear, though. While turkey populations in much of the U.S. are thriving, in the Southeast, their numbers are tumbling. That’s probably due to a number of factors, Wightman said, but shrinking habitats and poorer habitat quality are probably most responsible, and hunting regulations haven’t taken into account those declines.

Wightman hopes the paper encourages managers to reconsider turkey harvest rates. In previous years when populations were thriving, 30% harvest rates were sustainable, but that’s probably not true anymore, he said, when fewer poults are reaching adulthood. “We’re making half the number of birds,” he said.

This article features research that was published in a TWS peer-reviewed journal. Individual online access to all TWS journal articles is a benefit of membership.  Join TWS now to read the latest in wildlife research. 

Technique simplifies disease sampling in wildlife

December 29, 2023 by The Wildlife Society

A new technique could help track disease in wildlife. In a study published in the Journal of Agricultural, Biological and Environmental Statistics, researchers proposed a way to reduce the sampling necessary to accurately measure how widely a disease has spread. The method is based on the notion that, since animals tend to cluster in groups, sampling a single individual can suggest whether or not the others are also infected. Using chronic wasting disease in deer as a case study, researchers found their approach reached similar conclusions to conventional methods. They hope an online application in development could help biologists figure out how many animals to sample. Researchers believe the technique can save biologists time and money.

“The framework is so flexible, we can use it for any animals,” said co-author Krysten Schuler, assistant research professor in the Department of Public and Ecosystem Health at Cornell University.

Read more from Cornell Chronicle.

Here are the top 10 wildlife stories of 2023

December 28, 2023 by The Wildlife Society

African oryx running wild in New Mexico. Snake reintroduction. Human shields and predators.

These are just some of the most popular news stories The Wildlife Society has published in 2023, covering the gamut of cutting-edge research on conservation, wildlife management, and the policies that affect our ecosystems.

The past year has seen the beginning of the implementation of wolf reintroduction to Colorado as well as a partisan divide that has affected the passage of some wildlife legislation. But wildlifers have nonetheless made great discoveries in furthering our understanding of ecology and wildlife populations management.

Here is the list of our top 10 most popular stories of 2023.

10. USFWS issues new Colorado gray wolf designation

The Colorado public opted to return gray wolves (Canis lupus) to the state in a 2020 ballot box vote. To help ease some of the regulatory restrictions on wildlife managers who will be working on the issue, the U.S. Fish and Wildlife Service issued a “nonessential experimental population” designation for the canids in Colorado. This will help ease potential human-wildlife conflicts as the project gets underway, the agency hopes.

9. What’s the best way to translocate snakes?

Massassauga rattlesnakes (Sistrurus catenatus) are listed as endangered in Canada due to habitat fragmentation and low numbers there. It’s been years since scientists have attempted to translocate the species. To learn more about the most successful practices in snake reintroductions, in general, one research team examined more than 100 translocation cases in an effort to better inform any future snake management actions to conserve the massassauagas.

8. JWM: Why has elk recruitment declined in New Mexico?

Elk recruitment has been declining for years in New Mexico. One recent study pointed the finger at predators as being a possible reason for these population drops. But new research shows that climate change may also be playing a major role.

7. 10 years later, translocated turtles find their way home

In 2010, an oil pipe operated by Enbridge Inc. burst into a tributary near the Kalamazoo River in Michigan. The resulting disaster affected a huge amount of wildlife in the area, including turtles. Researchers who had rehabilitated and translocated turtles away from the affected area returned a decade later to see if these turtles had moved back to the places where they were removed from.

6. TWS2022: Do cougars use artificial water sources to ambush prey?

Pumas have been observed killing deer around artificial drinking sources. Researchers wanted to know whether the big cats were cuing into these stations as good places to ambush their prey. They found that while they weren’t directly using the drinking sources, they might be following ungulates to the general areas around them.

5. Window decals create sticky situation for deterring bird strikes

Window decals can sometimes be effective ways to keep birds from smashing into them. But researchers found their success is all about placement. Many people put them on the inside of windows, as they are often easier to place—especially for windows at the top of tall buildings. But researchers found that decals placed on the outside of windows were much more effective at reducing bird strikes than those placed on the inside of windows.

4. Human shields can be lethal for midsized predators

When large predators like wolves (Canis lupus) or pumas (Puma concolor) are around, some bobcats (Lynx rufus) and coyotes (Canis latrans) choose to move closer to humans, thinking that the ‘human shield’ is the safer of two bad options. But research reveals that humans may actually cause more danger to these mid-sized predators. Many bobcats and coyotes that moved closer to humans while larger animal predators were around were killed by hunters and trappers.

3. Tough regulations work best to stem wild pig invasion 

Since their introduction into the United States with European settlers, wild pigs have expanded quickly across the continent. Every state enforces different regulations to manage these pigs. Researchers examined the state of the invasive pig problem in many of these states and compared them with the effectiveness of each one’s regulations.

2. As the climate changes, wild turkeys aren’t keeping up

We’re more than a month past Thanksgiving, but the weather hasn’t cooled for wild turkeys (Meleagris gallopavo). Researchers have found that warmer, wetter weather early in spring may be throwing out of whack what used to be the birds’ nesting season. The invertebrate food they rely on may hatch earlier, meaning there won’t be enough for young poults if they hatch later on.

1. Rising oryx numbers may distress New Mexico ecosystem

You’d be mistaken if thinking that the best place to see South African oryx (Oryx gazella) this side of the Atlantic Ocean would be a zoo. The New Mexico Game and Fish Department first introduced these ungulates, also known as gemsbok, to the state as game animals, and they have taken off in some parts of the ecosystem there. The trouble is, these newcomers may outcompete native species like pronghorn {Antilocapra americana) and mule deer (Odocoileus hemionus) in New Mexico.

Bird feeding is not only for the birds

December 28, 2023 by The Wildlife Society

While researchers often focus on the effects of bird feeding on birds, what about the impacts of the activity on people? Some researchers argue that not only is it good for people, but it can also play a role in policy.

The team noticed that state agencies were advising people to stop feeding birds after a number of avian disease outbreaks in 2021. But these recommendations didn’t necessarily follow any evidence that bird feeding would increase disease spread, they found. What’s more, there wasn’t really a method of gauging if people were listening and how the guidelines impacted them.

Both the well-being of birds and of people need to be considered, the authors argue.

“The psychological benefits of bird feeding for humans are well-documented but often overlooked in management decisions in response to avian disease outbreaks,” they wrote in a study published in People and Nature.

“Ecological and social science need to be applied in tandem to ensure that well-intended guidance to cease feeding of birds does not have unintended consequences.”

Read the study in People and Nature.

Moon sheds new light on how ocelots and bobcats share the landscape

December 27, 2023 by David Frey

Both bobcats and ocelots roam the thornscrub of southern Texas. But while the cats may look similar and have similar diets, their behavior in the moonlight can be very different.

As part of their research into how the two species use the landscape they share, Maksim Sergeyev, then a graduate student at the Caesar Kleberg Wildlife Research Institute, and his team looked at a variety of factors, from topography to temperature. Then they wondered how the phase of the moon affects these two predators, which rely on surprise to capture their prey.

“If you think about it, it’s very different at night when it’s a full moon and there’s a new moon,” Sergeyev said.

In a recent study published in PLOS ONE, Sergeyev and his colleagues collared eight ocelots (Leopardus pardalis) and 13 bobcats (Lynx rufus). They compared their habitat selection under the full moon and during a new moon from 2017 to 2021. What they found gave them new insight into how two species that seem so similar can behave very differently on the same landscape.

“It shed new light on how they share their space,” Sergeyev said.

Ocelots are federally endangered, primarily occupying rugged private lands in southern Texas. They rely almost exclusively on thornscrub landscapes to hunt and to take shelter from the Texas heat. Bobcats use the same landscapes, but they are more generalist, Sergeyev said, using the edges more than ocelots.

Ocelots are also highly nocturnal, while bobcats are more likely to hunt in the evening. As a result, researchers found, moonlight can mean very different things to them.

Ocelots, they discovered, didn’t change their habitat selection based on the phase of the moon, but they did change their movements. Under the full moon, they moved shorter distances. That may be because the bright moonlight blew their cover from predators. The darkness of new moons, however, allowed them to travel farther without being detected.

Bobcats, on the other hand, sought denser vegetation during full moons. That’s probably because they need more cover in the brightness. But their movement remained the same, regardless of the moon. 

The findings could have conservation implications for ocelots.

“The biggest source of mortality for ocelots is vehicle collisions,” Sergeyev said. Since ocelots are more on the move on moonless nights, informing the public to be more cautious on dark nights could help the species persist.

Bringing back European bison

December 27, 2023 by The Wildlife Society

After uncovering the reasons for the near-extinction of bison in Europe, researchers think they have some clues for successfully increasing populations there. Herds of European bison (Bison bonasus) used to roam Europe until 1927 when they became extinct in the wild. Since then, efforts to reestablish the species have resulted in 7,300 free-ranging bison, but those reintroductions were done without a good understanding of the species on the continent. In a study published in Proceedings of the Royal Society B Biological Sciences, scientists used fossil evidence, ancient DNA and modeling to determine what caused the European bison to initially decline. They found that environmental change and hunting by humans were the main causes. Using this information, they determined areas most suitable for the species today.

Read the study in the Proceedings of the Royal Society B Biological Sciences.  

JWM: Invasive pythons may affect bobcats in the Everglades

December 26, 2023 by David Frey

As Florida officials work to restore water levels in the Everglades, they wondered what effect it may have on bobcats there.

Biologists don’t know much about the big cats in the national park. But they did know they use tree islands—areas just a few inches higher in elevation than the surrounding wetlands. Those islands can support woody plants that don’t survive in the sawgrass waterways.

But as biologists explored bobcats in the national park, they found that invasive Burmese pythons (Python molarus bivittatus)—which are altering the Everglades’ ecosystem—potentially pose a greater threat to bobcats than changing water levels.

For a study published in the Journal of Wildlife Management, Katie Buckman, then a master’s student at Florida Atlantic University, and her colleagues set out to determine how bobcats (Lynx rufus) were using the tree islands in the Everglades. State biologists had seen them showing up in trail camera images, but they didn’t know much about the cats’ habitat use or response to fluctuating water levels.

The biologists were particularly interested in this topic, since plans called for restoring Everglades water levels to historical conditions. Diversions have siphoned water away from the “river of grass” for decades, transforming the unique ecosystem, while the construction of levees and highways have caused pooling of deep water in other areas.

“The Everglades need water,” Buckman said, yet no one knows how bobcats might respond to different water levels.

As Buckman and her team modeled habitat use for bobcats, though, they found little evidence that water levels affected bobcat habitat use, but the python invasion may be.

“The project started out looking at habitat use,” she said. “What ended up happening was, we couldn’t really ignore the Burmese python problem.”

Raised as pets and released into the wild, Burmese pythons have thrived in the Everglades, despite teams of python hunters dispatched to remove the voracious predators from the landscape. The constrictors eat the same small mammals that bobcats prey on, so as python numbers increase, they may create more competition for the cats.

As they created occupancy models, Buckman and her team expected that higher water levels would jeopardize bobcat numbers by limiting their access to tree islands, but that’s not what they found. Instead, they found that a wetter Everglades appeared to poselittle risk to bobcats, but the presence of pythons did.

Once pythons reached a density of more than three per square kilometer, “bobcat occupancy was significantly diminished,” researchers wrote in their study.

“Our results suggest that while hydrologic dynamics may play a role,” they concluded, “the invasive Burmese python has stronger influences on bobcat occupancy of tree islands in this Everglades conservation area.”

It was a bit of a surprise, Buckman said. Bobcats are highly adaptable, but invasive pythons are tough competitors.

This article features research that was published in a TWS peer-reviewed journal. Individual online access to all TWS journal articles is a benefit of membership.  Join TWS now to read the latest in wildlife research. 

Cats eat diverse smorgasbord of wildlife

December 26, 2023 by The Wildlife Society

It’s well known that free-ranging cats eat lots of birds and rodents. But researchers recently documented cats around the world eating 2,000 species, including reptiles, mammals, even a number of insects, like monarch butterflies (Danaus plexippus) and emperor dragonflies (Anax imperator). Even more surprising, the study in Nature Communications uncovered evidence of cats scavenging species such as camels, cows and endangered green sea turtle (Chelonia mydas) hatchlings. The researchers’ findings came from a search of published and unpublished literature on cat predation.

“Domestic cats (Felis catus) are beloved companions for many people, but they are also invasive predators that have been linked to numerous birds, mammals and reptiles going extinct,” said Andrew Mitchinson, an editor at the journal Nature, in a related article.

Read more in USA Today.