“Burrowing owls materialize on southeast Wyoming grasslands,” published July 29, 2018 in the Wyoming Tribune Eagle and at Wyoming Network News, https://www.wyomingnetworknews.com/burrowing-owls-materialize-on-southeast-wyoming-grasslands.
Burrowing owls materialize on southeast Wyoming grasslands
By Barb Gorges
Burrowing owls were like avian unicorns for me until this spring. Mark, my husband, and I searched prairie dog towns in southeastern Wyoming to no avail.
It wasn’t always like that. Fifteen years ago there was a spot on the east edge of Cheyenne guaranteed to produce a sighting for the Cheyenne Audubon Big Day Bird Count. But the area around it got more and more built up.
I did some research through my subscription to Birds of North America, https://birdsna.org and discovered burrowing owls don’t require complete wilderness.
These owls are diurnal—they are active during the day, most active at dawn and dusk. However, when the males have young to feed, they hunt 24/7.
The eggs are laid in old animal burrows, primarily those of prairie dogs. Because prairie dogs live in colonies, the burrowing owls tend to appear in groups, too, though much smaller. Besides nesting burrows, they have roosting burrows for protection from predators. They stockpile prey in both kinds of burrows in anticipation of feeding young. One cache described in a Saskatchewan study had 210 meadow voles and two deer mice.
Western burrowing owls, from southwestern Canada to southwestern U.S., winter in Central and South America. However, there are year-round populations in parts of California, southernmost Arizona and New Mexico and western Texas and on south. But there is also a subspecies of the owl that lives in Florida and the Caribbean year-round. They excavate their own burrows.
Burrowing owls breed in the open, treeless grasslands. No one is sure why, but they like to line their nesting burrows with dung from livestock. They, along with their prairie dog neighbors, appreciate how grazing animals keep the grass short. It’s easier to see approaching predators.
The owls’ biggest natural nest predator is the badger. Both young and adults can scare predators away from their burrows by giving a call that imitates a rattlesnake’s rattle.
Short grass means it’s easier to catch prey by walking or hopping on the ground as well as flying. Burrowing owls also like being near agricultural fields.
The fields attract their primary prey species: grasshoppers, crickets, moths, beetles, and in addition to small mammals like mice and voles, shrews.
You would think these owls are ranchers’ and farmers’ best friends. However, in the Birds of North America’s human impacts list are wind turbines, barbed wire, vehicle collisions, pesticides and shooting. I’m surprised by shooting.
Since western burrowing owls can’t be blamed for making the holes in pastures (they only renovate and maintain burrows by kicking out dirt) I can only surmise that varmint hunters have bad eyesight and can’t tell an owl from a prairie dog. It could be an easy mistake: Owls are nearly the color and size of prairie dogs and have similar round heads. Except the owls stand on long skinny legs. From a distance the owls look like prairie dogs hovering over the burrow’s mound—and then if you watch long enough, they fly.
Burrowing owls have been in sharp decline since the 1960s despite laying 6 to 12 eggs per nest. The Burrowing Owl Conservation Network, http://burrowingowlconservation.org, reports the U.S. Fish and Wildlife Service lists them as “a Bird of Conservation Concern at the national level, in three USFWS regions, and in nine Bird Conservation Regions. At the state level, burrowing owls are listed as endangered in Minnesota, threatened in Colorado, and as a species of concern in Arizona, California, Florida, Montana, Oklahoma, Oregon, Utah, Washington, and Wyoming.”
In our state, Grant Frost, Wyoming Game and Fish Department wildlife biologist, said “(burrowing owls) are what we classify as a species of greatest conservation need (SGCN), but mostly due to a lack of information; their status is unknown. That is why these surveys were started three years ago. There are 15 surveys being done throughout the state in potential habitat…each survey route is done three times each year during set times to occur during each of the three nesting stages – pre-incubation, incubation/hatching, and nestling.”
When Grant said he could lead an Audubon field trip to see the owls and other prairie birds, 15 of us jumped at the chance.
As might be predicted from the BNA summary of the literature, the owls were in the middle of an agricultural setting of fields and pastures. We watched them hunt around a flock of sheep and enjoy the view from the tops of fence posts along an irrigation canal.
The first sightings of the morning were distant—hard to see even with a spotting scope. But as we departed for home, driving a little farther down the road, two burrowing owls appeared much closer and we all felt finally that we could say we’d seen them and not just flying brown smudges.