Collisions with windows are a leading cause of death for urban raptors in New Mexico, researchers found. But the biologists also uncovered another troubling cause of death. Humans had intentionally killed eight tagged hawks, some of which were bludgeoned to death.
Over 11 years, TWS member Brian Millsap and his colleagues at the U.S. Fish and Wildlife Service fitted Cooper’s hawks (Accipiter cooperii) in Albuquerque with GPS transmitters. When the birds died, researchers were able to determine what caused their deaths.
In a study published in the Journal of Raptor Research, the team looked at causes of deaths for female raptors in their first year, when the birds are more vulnerable, and after their first year.
Mortality was highest in the first four months of independence, researchers found. Regardless of age, disputes over territory or mates were the leading cause of death. Collision deaths were also high, but Millsap was surprised how many hawks were intentionally killed.
“I, like many others, had been falsely thinking that the days of rampant hawk shooting the U.S were behind us, but we are learning that is not the case.”
Warming weather is contributing to bowhead whales moving the time and location of their migration in the Arctic.
Most baleen whales—cetaceans that use a filter-feeding system to eat—migrate to higher latitudes and have long migration routes and distinct feeding and breeding regions.
But bowhead whales (Balaena mysticetus) live exclusively in the Arctic and make more of a circular migration. Their wintering grounds are in the southern Bering Sea, then they migrate northward through the Bering Strait, a narrow connection leading to the Arctic Ocean. Once there, they take a hard right and follow the coast of Alaska to the Canadian part of the Beaufort Sea, where they typically feed in the summer. But on their return to their wintering grounds, they typically take a more roundabout way through the Chukchi Sea before crossing back through the Bering Strait.
“I knew that things were changing pretty rapidly in the Arctic,” said Angela Szesciorka, a research associate at Oregon State University and the lead author of a study looking at bowhead whale migrations published in Geophysical Research Letters. She wondered if sea ice loss was going to start changing the patterns of their migration paths and timing.
Three bowhead whales breathing near ice. Credit: Kate Stafford
For Szesciorka’s PhD research, she had been studying blue whales (Balaenoptera musculus) in Southern California using passive acoustic data. She used their calling patterns to determine when they arrived in the region and when they left. She wondered if she could use this same technique to study the migration patterns of bowhead whales.
Luckily for Szesciorka, some of her colleagues had already been deploying hydrophones, or underwater recorders, for years in the western Beaufort Sea and Chukchi Sea. The researchers then examine the sound spectrograms, searching for the unique signatures of bowhead whale vocalizations. “It’s a wonderful system,” she said.
These particular recorders were left out for about a year or two at a time before they were replaced. They provided Szesciorka with data from 2008 to 2022 that could help her understand how sea ice loss may have changed the whales’ travel patterns. “It’s really fun as you’re going through it, but it’s tough too,” she said. Blue whales, for example, have simple patterns that are easy to identify—researchers can even use artificial intelligence programs. But bowheads have “complex songs” that are often overlapping with noise from other animals and the environment, making it difficult to use algorithms to identify them.
A bowhead whale song from the Bering Strait recorded in January 2011.
After the arduous task of analyzing the data, Szesciorka found that instead of all of the whales going into the Bering Sea, some are now spending their winters just north of the Bering Strait in the southern Chukchi Sea. They are also spending more time in the summer feeding in the Chukchi Sea.
Szesciorka said this is likely due to the food availability there. A warming climate may be changing nutrient pulses, and therefore, the distribution of krill and copepods that the bowhead whales feed on, she said. “Bowhead whales are opportunistic. They will feed whenever they can,” she said.
The recordings also suggested that the whales had shifted their winter departure from the western Beaufort Sea 45 days later in 2022 than they had in 2008. “With less sea ice out there, they stay longer for the season,” Szesciorka said.
These changing patterns can be challenging for Indigenous people who subsist on bowhead whales. There are 20 villages from three federally recognized Indigenous groups around the Bering Strait, she said.
Szesciorka is also concerned about the whales now coming into contact with more boats. She is currently looking at vessel trends in the Arctic, and has found that vessels are overlapping in the fall and winter with bowhead whale presence in the Chukchi Sea and Bering Strait. Boats can kill whales through strikes, and the noise the vessels make can hinder the marine ability to communicate.
Creating dynamic speed limit zones or banning traffic in areas where there are whales, could potentially mitigate these issues. Right now, Szesciorka said, there are no speed limits or other regulations. But multiple Tribes, states, provinces and countries would need to collaborate in many cases since the whales don’t abide by human-set boundaries. “How do you create rules and know everyone’s going to follow them?” she said.
The silver lining is that the whales have been able to adjust their migration in the face of climate change. But her fear is that “when things get more and more extreme, at some point you can’t keep adjusting.”
The U.S. House of Representatives recently passed the Wildlife Innovation and Longevity Driver (WILD) Reauthorization Act (H.R. 5009), a bipartisan effort to reauthorize funding for several wildlife and habitat conservation programs.
“We are one step closer to ensuring that our children and grandchildren will inherit a world rich in biodiversity,” said Rep. Dave Joyce (R-OH), co-chair of the International Conservation Caucus, who sponsored the act. The passage of this legislation in the House signals gaining momentum for wildlife conservation efforts. The WILD Act supports funding two different initiatives: the Partners for Fish and Wildlife Program and the Multinational Species Conservation Funds.
Across all 50 U.S. states and territories, the U.S. Fish and Wildlife Service’s Partners for Fish and Wildlife Program offers critical support for voluntary conservation initiatives. Various organizations, including landowners, Tribes and nonprofits interested in improving wildlife habitat, can apply for free technical and financial assistance through the program. The program has made possible more than 50,000 projects, including the restoration and management of six million acres of forest, prairie, wetland and stream habitats since 1987.. The Wildlife Society has supported sustained funding for the Partners for Fish and Wildlife Program, demonstrating a commitment to collaborative federal conservation efforts.
The Multinational Species Conservation Funds play a pivotal role in supporting the conservation of imperiled species globally, including iconic wildlife such as rhinos, elephants, tigers, great apes and marine turtles. “In the over 30 years since its inception, the Multinational Species Conservation Funds have been an incredibly successful tool in strengthening global wildlife conservation, helping conserve our planet’s most iconic and beloved wildlife species,” said Rep. Debbie Dingell (D-MI). , “I’m glad to see the WILD Act pass in the House to ensure we can continue this important work to protect these species for generations to come.”
Through partnerships with other countries, the United States contributes to conservation efforts in regions facing significant biodiversity threats, such as the Amazon rainforest and the coral reefs of the Pacific Ocean. “Around the world, habitat loss and climate change continue to threaten wildlife,” said Chairman Tom Carper (D-DE). The provisions of the WILD Act align with the goals of these global objectives and demonstrate the U.S. commitment to international wildlife conservation efforts.
The Wildlife Society has long advocated for the importance of endangered species recovery, recognizing the vital role threatened and endangered species play in maintaining healthy ecosystems. This commitment is evident through our position statement on the Conservation of Biological Diversity, as well as issue statements addressing the U.S. Endangered Species Act and policy briefing on the Species at Risk Act, which highlight our dedication to supporting international and endangered species recovery efforts.
The next critical step for the WILD Act lies in the Senate, where it will undergo further review and consideration. The identical Senate version (S. 2395) introduced by Senators Shelley Moore Capito (R-WV) and Tom Carper (D-DE) in July 2023, reflects bipartisan support for conservation efforts across both chambers.
“The WILD Act enables the U.S. Fish and Wildlife Service to promote voluntary conservation here at home, while also ensuring that the United States remains a global leader in protecting some of our world’s most beloved species,” Carper said, emphasizing the bill’s significance in maintaining the nation’s commitment to domestic and global wildlife conservation efforts.
The government of British Columbia is working with the Tobacco Plains Indian Band to collect samples from deer to test for chronic wasting disease.
The samples will come from the Kootenay region, where two deer—a mule deer (Odocoileus hemionus) and a white-tailed deer (O. virginianus) tested positive for the fatal prion disease earlier this year.
The Ministry of Water, Land and Resource Stewardship is permitting the band to collect 20 mule deer and five white-tailed deer by the end of March in a 10-kilometer area surrounding the sites where the previous animals were found. Officials hope to see if more B.C. deer have the disease, which affects cervids and is always fatal.
Since the disease was discovered in the area, the province has restricted transportation of carcasses and required testing for any deer, moose (Alces alces), elk (Cervus canadensis) and caribou (Rangifer tarandus) killed on the road.
Black-footed cats depend on the burrows that other animals dig in the grasslands of southern Africa.
But these vulnerable, tiny cats—which may be the rarest wild felines in Africa—may lose their habitat if the South African springhares that dig these holes are locally extirpated from some areas.
“The most important thing I found is that we need to preserve springhare if we want to save the black-footed cat,” said TWS member Hal Brindley, website administrator for the American Chestnut Foundation.
Credit: Hal Brindley/Travel For Wildlife
Cat mission
Black-footed cats (Felis nigripes), which the International Union for Conservation of Nature lists as vulnerable, are found in southern Africa, mostly in Namibia, South Africa and Botswana. These felines are about a third the size of a house cat and are hard to detect due to their tiny size and nocturnal lifestyle.
When completing his master’s degree at the University of Cape Town in South Africa, Brindley decided to focus his work on black-footed cats, which were understudied compared to larger felines like leopards (Panthera pardus) or lions (P. leo) in the region. “Plus, they are really ridiculously cute, which helps,” he said.
Credit: Joshua Learn
As detailed in a presentation at The Wildlife Society’s 2023 Annual Conference in Louisville, Kentucky, Brindley and his colleagues conducted their research at a field site on private property used for sheep grazing in Grunau, a small settlement in southern Namibia. The study, which involved collaboration with conservation organizations, including the Black-footed Cat Research Project Namibia and the Black-footed Cat Working Group, lasted for four weeks in 2022.
Credit: Hal Brindley/Travel For Wildlife
When the team started, six known female cats roamed the 70,000-hectare site, but they found one of them dead on the first day of the study. These cats were all fitted with VHF tracking collars for ongoing research. Four of the surviving cats were either pregnant or had kittens.
The team drove around, tracking cats via their VHF collars. This involved a lot of traveling—despite their small size, black-footed cats have a home range of about 40 square kilometers in this area. Once the researchers got close to a signal, they started off on foot. They recorded where the cats denned during the day and followed them by vehicle at night. The researchers would get within 20 meters of the cats, though the animals would sometimes circle back and come right up to the researchers’ truck.
Credit: Hal Brindley/Travel For Wildlife
While it wasn’t their main focus, Brindley watched the cats hunt birds and rodents, though the small animals were easy to lose in the grass. “What’s really weird about these cats is that they have a really high metabolic rate,” he said, comparing their flitting movements to chipmunks. “Everything was sped up.”
Credit: Hal Brindley/Travel For Wildlife
Once they verified and recorded which burrows the cats used, they waited for the felids to leave and measured the size and dimensions of the openings using a Light Detection and Ranging (LiDAR) scanner on an iPad.
Cat videos for science
Before getting out in the field, Brindley had indulged in numerous YouTube videos of house cats squeezing through small openings. He’d taken rough measurements of what spaces cats could get into based on their size as a way of estimating how black-footed cats might fit into burrows of various dimensions. He estimated that black-footed cats might prefer burrows with openings of 10–20-centimeter diameters.
His cat video calculations proved fairly accurate when Brindley analyzed his field data. In their study area, black-footed cats almost entirely used the burrows that springhare (Pedetes capensis) dug.
Credit: Hal Brindley/Travel For Wildlife
Springhares, Cape ground squirrels (Xerus inauris) and aardvark (Orycteropus afer) all dig burrows in this area, while aardwolves (Proteles cristata), bat-eared foxes (Otocyon megalotis), Cape porcupines (Hystrix africaeaustralis) and Cape foxes (Vulpes chama) modify the burrows springhare and aardvark dig. The size of springhare burrows, before modifications, are between the size of aardvark and ground squirrel burrows. While springhare don’t face threats overall, sport hunters target springhares, while farmers often consider them a nuisance.
The cats inhabited an average of 11 different burrows during the four weeks that Brindley and his team were in the field. Cats spent an average of 2.2 consecutive days in a den before moving to a new one. The ones with kittens would use a den for an average of six days but never return to the same den after they left it. That may have been a tactic to evade predators after the cat left its scent there, Brindley said.
Credit: Hal Brindley/Travel For Wildlife
Once their kittens were six or seven weeks old, the adult females would also drastically change their strategy, shifting dens every day. Brindley said this likely reflects the fact that the kittens come along with them on their nightly hunts—the family would stop wherever they ended up around dawn.
Most burrows the cats used seemed abandoned. In other situations, Brindley speculated that they didn’t seem to be affected by the presence of the intruders. Despite the name and their rabbit-like appearance, springhares are actually rodents. These small creatures dig vast burrow systems—they can be 30 meters in diameter, with passages heading off in every direction and a dozen different entrances. The cats typically didn’t go too deep inside, and only used a single entrance, so the springhares were likely able to continue using the burrows.
Credit: Hal Brindley/Travel For Wildlife
While black-footed cats elsewhere may use other animals’ burrows, or even termite mounds that aardvarks excavate, this research reveals that black-footed cats are often heavily dependent on springhare in this part of Namibia. Brindley said this is likely because larger burrows aardwolves and foxes dig might not be as safe for the felines, especially when the kittens are young and left alone at night. Predators like black-backed jackals (Canis mesomelas) or even caracals (Caracal caracal) might be able to enter.
The low-intensity, rotated grazing of ranchlands creates the kind of grassland habitat favorable for the cats and their rodent prey, Brindley said. These cats aren’t really persecuted, as humans hardly see them—accidental capture in traps or via poisoned baits set for other small predators or jackals might be the biggest threat they face directly from humans.
Credit: Hal Brindley/Travel For Wildlife
But sheep farmers also kill jackals, such as the one above eating a meerkat (Suricata suricatta), over fears these canids may kill livestock, which also removes a potential predator of black-footed cats. Working with farmers to conserve springhare habitat may be the best way to conserve black-footed cats, Brindley said.
The Wildlife Society Bulletin is an open-access journal of 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.
As duck hunting has declined, researchers have looked at ways to bolster the activity. Wildlife professionals assumed simpler regulations would help recruit new hunters, but bag limits can be confusing. In a study in the March issue of the Wildlife Society Bulletin, researchers sought to understand hunters’ understanding and compliance with regulations.
Other articles look at using drones to count kangaroo rat burrows, bald eagle predation on threatened murrelets, LGBTQ+ inclusion in wildlife and more.
Wildlife managers are developing photographic methods to track sandhill crane population changes across their range, which can be useful in informing hunting regulations.
Managers sometimes track harvest data and trends for game bird species by analyzing bird wings and parts that hunters sometimes mail into the U.S. Fish and Wildlife Service. Wildlife managers then classify them by age, sex and species where possible, to determine any long-term shifts in populations.
Sandhill crane (Antigone canadensis) harvest is legal in North Dakota, as in many other states. But the tall, gawky birds’ large wingspans and spindly legs make their parts impractical to collect for wildlife managers. The most feasible way to determine subspecies and age would be to measure the length of their leg bones and part of their bill—from the back of their nostril to the tip of their beak.
As a result, wildlife managers have never really had a good way of tracking the age and subspecies trends of birds across their range.
“Right now, we just don’t have that information,” said Andrew Dinges, a supervisor in the private lands section of the North Dakota Game and Fish Department.
Photographic evidence
Dinges, who was a migratory game bird biologist at the time, wanted to see if newer technology might provide a better way to assess any changes in the midcontinent sandhill crane population that migrates through North Dakota. This information could protect sandhill cranes when they’re vulnerable, while also offering more hunting opportunities when the birds are abundant.
He turned to photography, since most hunters carry smart phones—a much cheaper and more practical option than sending bulky parts through the mail. He led a study on his findings, published recently in the Wildlife Society Bulletin.
Starting in 2019, Dinges asked volunteers to mail him crane legs and bills. In the lab, he developed a way to accurately measure the size of parts of the bill and legs by taking photos of them next to an object of known length. Using computer software, he could digitally measure these parts to predict the age and subspecies of sandhill cranes, which are divided into lesser (A. c. canadensis) and greater sandhill cranes (A. c. tabida).
Using a measure of the actual bird parts and a measure of the parts in photographs that he took, Dinges developed correction formulas for predicting actual part length based on photos.
In the second phase of his research, Dinges mailed a block of wood of known length to participants along with instructions on how to upload the photos they took to a database. Participants were told to take photos of the crane parts with the block next to it for reference. He wanted to test if hunters were capable of taking photographs that could be used to digitally measure parts.
While conducting his research, Dinges found it was more difficult for hunters to take accurate photos of legs due to the difficulty of laying out those parts needed for measurement. This caused a drawback in terms of accuracy—to best determine whether a given crane is a lesser or greater sandhill, the leg bone measurement increases the accuracy of subspecies prediction.
An example of the kind of photo that Andrew Dinges used to calculate the length of parts of the bills and legs of cranes. Credit: Andrew Dinges
For ease of use, he decided that only focusing on the beak and head would probably ensure better participation and data gathering. “Hunters were more likely to participate with that collection method,” Dinges said.
Dinges said that it’s still possible to estimate the subspecies by just using bill measurements, though it isn’t as accurate as if you obtained the measurement of parts of the leg as well. Still, Dinges said this information can help wildlife managers throughout the central flyway. For example, western North Dakota has higher daily bag limits for hunters since the majority of these birds are lesser sandhill cranes in that area. In the east of the state, there is a lower daily bag limit since greater sandhill cranes frequent this area more.
“If we had subspecies information, you could really start to fine-tune that line in North Dakota,” Dinges said about the geographical divide between lesser and greater sandhill cranes.
He hopes that state and federal agencies can employ this new technique to help track changes in sandhill crane populations. But since it’s a migratory bird, he said it will be important for the different states and Canadian provinces in the flyway to collaborate to get a more accurate picture.
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.
A global study using data from before and during COVID-19 lockdowns found wild animals have different responses to the presence of humans.
Carnivores like wolves (Canis lupus) and wolverines (Gulo gulo) tend to be less active when humans are around, preferring to avoid risky encounters. That’s good news for herbivores like deer and moose (Alces alces), which tend to become more active. So do urban animals, like racoons (Procyon lotor). But animals in rural areas are warier.
The study, published in Nature Ecology & Evolution, involved more than 220 researchers analyzing 163 mammal species and found on 5,000 camera traps around the world.
“COVID-19 mobility restrictions gave researchers a truly unique opportunity to study how animals responded when the number of people sharing their landscape changed drastically over a relatively short period,” said TWS member Cole Burton, an associate professor of forest resources management at the University of British Columbia and the study’s lead author.
“And contrary to the popular narratives that emerged around that time, we did not see an overall pattern of ‘wildlife running free’ while humans sheltered in place,” Burton said. “Rather, we saw great variation in activity patterns of people and wildlife, with the most striking trends being that animal responses depended on landscape conditions and their position in the food chain.”
The return of wolves to Yellowstone National Park, as well as the comeback of other predators, may not restore wetland ecosystems there as much as some scientists had hoped.
Gray wolves (Canis lupis) were extirpated in the park by the 1920s due to predator control efforts. But in the 1990s, wolves were reintroduced. At the same time, other predators, including grizzlies (Ursus arctos horribilis) and cougars (Felis concolor), began naturally returning to the area. Many have theorized that predation on elk (Cervus canadensis), which overgraze vegetation if left unchecked, has helped the ecosystem recover to its more historical state.
But research assessing the system for 20 years tells a different story. “There’s a lot of research analyzing ecosystems after predators are removed,” said David Cooper, a senior research scientist emeritus in the Warner College of Natural Resources at Colorado State University. But studies on reintroducing predators back into the ecosystem are harder to come by. “We weren’t really sure what to expect.”
Cooper and his colleague Tom Hobbs, an emeritus professor at Colorado State, were the senior authors of a study published in Ecological Monographs analyzing how the wolves’ and other predators’ returns affected riparian willows.
Beaver extirpation
In the past, elk fed heavily on willows, a riparian plant. In turn, beavers (Castor canadensis), no longer had food and material to build dams and raise the water table. Beavers were extirpated from this region of the park by the 1940s due to a lack of willows and from overharvesting them.
“These small streams had gone from a beaver-willow system, which was wet and dynamic, to an incised, dried-up floodplain that we call the elk grassland state,” Cooper said. He and his colleagues wanted to find out what bringing wolves back did to what he calls the “alternative elk-grassland state”—an ecosystem that had shifted entirely from its original state.
Cooper and Hobbs began working on this system in 2001. In the park’s northern range, they fenced off eight plots to prevent elk browsing. They constructed simulated beaver dams in some enclosed and non-enclosed plots to mimic how beavers would raise the water table. They chose where to create these based on a report from Cornell University, where scientists mapped out beaver colonies in Yellowstone in the 1920s. In addition, the team left some areas as controls. “This is a fully factorial experiment,” Cooper said. “We could test the effect of browsing versus water availability compared to the controls.”
After analyzing the willows in these plots, the team found that the shrubs had grown in the control plots, but not as much as you might expect. Even with all three predators in the ecosystem, the researchers found that browsing wasn’t really reduced all that much in the control plots. “We saw modest growth of willows in our 20-year experimental control plots,” he said.
Researchers tested how fencing and beaver dams may bring back willows in Yellowstone. Credit: David Cooper
What they did find was that in plots with simulated beaver dams and reduced browsing, willows did grow several meters tall. “But in sites where we just removed the browsing, they didn’t respond nearly as much as we would expect,” he said. That’s because these willows need water and didn’t get much without the simulated effects of beaver.
Overall, “the trophic cascade wasn’t really reinvigorated,” he said. “In other words, even with abundant predators, there was still extensive herbivory on our plants by elk and also bison.”
While elk populations have gone down, he added, bison (Bison bison) populations have gone way up. Wolves can’t really prey on bison because of their size, and bison also eat much more than elk do.
Other researchers have deduced similar findings about wolf reintroduction having less of an effect on aspen recovery in Yellowstone than initially thought.
But Cooper said this doesn’t mean wolves shouldn’t be introduced to their native ranges. “I believe that wolves are native animals,” he said. “They should be a part of our ecosystem, and they never should have been removed. The key is to maintain ecosystems intact, and then you never face these cascading issues or develop these alternative states that become stable and can’t be reversed.”
This is relevant now as wolves are being reintroduced to Colorado, although the situation there is a bit different than in Yellowstone. For example, elk hunting is allowed in Colorado, but it isn’t in Yellowstone. “I think the effects of wolves [in Colorado] will be even less than they were in Yellowstone,” he said. “We have a huge elk population [in Colorado] that’s well understood and carefully managed.”
On a research cruise focused on marine mammals and seabirds, Oregon State University scientists earned an unexpected bonus: the first-ever documented sighting of a hoary bat flying over the open ocean.
The bat was seen in the Humboldt Wind Energy Area, about 30 miles off the Northern California coast. The Humboldt area has been leased for potential offshore energy development, and the hoary bat (Lasiurus cinereus) is the species of bat most frequently found dead at wind power facilities on land.
OSU faculty research assistant Will Kennerley, the first to see the bat, and colleagues documented the sighting in a paper in the Journal of North American Bat Research.
Kennerley and Oregon State marine ecologist Leigh Torres were taking part in the MOSAIC Project, which studies seabirds and marine mammals around potential offshore wind energy areas.
“This demonstrates the value of having observers out on the water ready and able to document unexpected observations like this,” Kennerley said. “I think surprises like this are one of the most exciting parts of doing science.”
