Wildlife Science: Snow Hunting Owls; Is Beekeeping Bad?

How great gray owls hunt beneath the snow; why beekeeping may be bad for native pollinators; the benefits of bird feeders; more wildlife & science news

By Mark Wexler
Scope
Dec 30, 2023

Hunting Below the Snow

By hovering a few seconds midair above a spot where it senses prey, a great gray owl (above) can pinpoint and capture a vole hidden beneath as much as 2 feet of snow with astonishing accuracy. “These aren’t the only birds to hunt this way, but they are the most extreme because they can locate prey so far beneath the snow cover,” says Christopher Clark, a University of California, Riverside biologist who led a study to discover how the owls use sound to snag their prey. Conducting experiments on Canadian prairies with acoustic cameras and other equipment, Clark and his colleagues found that only lower-frequency sounds can penetrate deep snow. Large “facial discs” are more sensitive to these low-frequency sounds, and great grays have the largest faces of any bird species, the scientists report in the Proceedings of the Royal Society B. The predators use their faces to funnel the sounds of buried voles toward their ears—located right behind each eye—before punching through the snow with their powerful talons.

An image of blue tits and great tits around a bird feeder in a snowstorm.

Feeding Birds for Fewer Fevers

Providing seeds, nuts and other bird-feeder foods to small birds during winter can help the animals survive the cold months, Swedish scientists report in the Journal of Animal Ecology. “Our study shows that this feeding can have a positive effect on the capacity of small birds to fight an infection,” says lead author Hannah Watson, a Lund University biologist. Using equipment that measures body temperature, Watson and her colleagues monitored the health of two groups of wild great tits (above, with one blue tit) during winter. They found the birds that had regular access to feeder food could maintain lower body temperatures, which helped them live through cold nights and use less energy to fight off infection. By contrast, the great tits that did not have access to extra food had to burn more energy to raise body temperatures enough to battle infection, making them more susceptible to the cold. The scientists say that winter feeding not only helps support the health of small birds; it also provides people with more opportunities to engage with nature, particularly in urban areas.

An image of a beekeeper inspecting her hives full of bees.

Beekeeping Stings Native Bees

Touted as a way to “save the bees,” raising European honey bees (above) may instead be harming native North American bees, scientists report in PeerJ. At 15 sites around Montréal, Canada, the researchers compared data collected on 180 wild bee species in 2013 with 2020 data from the same sites. During that time, honey bee colonies in the city had increased from about 240 to nearly 3,000. “We found that the sites with the largest increase in honey bee populations also had the fewest wild bee species,” says lead author Gail MacInnis of Alberta’s National Bee Diagnostic Centre. Most native bees, she explains, are solitary, and some are active for just two or three weeks a year, meaning competition from a single hive of some 50,000 honey bees can deprive natives of vital pollen and nectar. “Urban beekeeping is often falsely marketed as a solution to biodiversity loss,” says co-author and Concordia University ecologist Carly Ziter. But “we’re much better off planting pollinator gardens than adding more hives” of nonnative honey bees.

An image of an Adélie penguin on an iceberg.

Microscope

Climate and Big-Bodied Birds

Rising global temperatures have reduced offspring production in migratory and large-bodied birds (such as Adélie penguins, pictured) but not in small and sedentary species, scientists report in the Proceedings of the National Academy of Sciences.