Take two: the continued travels of hawk 264292
You may recall our 2024 blog post about a radio-tagged ferruginous hawk fledgling, dubbed 264292 after her transmitter number. At the time, 264292 was moving from Lamar, Colorado to a prairie dog town in southwest Nebraska, about 160 miles away. Ferruginous hawks from Washington state generally winter in California, but 264292 is apparently not your average hawk.
She headed back north to the southwest corner of Nebraska where she has settled into the very southern extent of the sandhills. There, among the mixed agriculture and native prairie, she’s bounced around various prairie dog towns in the area, apparently having found a steady food source. At this point in the winter, it seems likely she will stay in that area until spring, when WDFW raptor experts expect she will likely wander across Oregon, Idaho, and Montana in her migration before eventually heading back home to Washington.
The yellow dots in the map above represent daily downloaded locations for hawk 264292 while in her winter range in southwest Nebraska.
This satellite photo shows foraging locations (marked with red dots) of hawk 264292 among prairie dog mounds (light dots).
In addition to WDFW’s ferruginous hawk radio-tagging work, our scientists have also been investigating the prey species on which hawks rely. Across most of their range, ferruginous hawks rely on large rodents, particularly ground squirrels, prairie dogs, and jackrabbits. With ground squirrels and jackrabbits being extirpated from southeast Washington, where Hawk 264282 was hatched, we are curious to learn what hawks are foraging on instead.
To do this, WDFW placed trail cameras (funded by Woodland Park Zoo’s Living Northwest Conservation Program, along with camera mounts and transmitters) at platform nests across Walla Walla County. With hawk 264292 seemingly settled in for the winter, it’s a good time to look back at her parents’ feeding activity before she was hatched. The following photos highlight some interesting behaviors and prey choices brought to the nest.
Prior to hawk 264292’s existence, while the female ferruginous hawk worked on making the nest bowl, the male arrived to copulate with her. The male clenches his talons so the female is not injured during breeding.
Next, the female settles in for incubation and the male brings a dried cow patty to the nest. Romantic? Not exactly, but it is thought that the dung works as a natural insect repellant to limit fleas and mites that are attracted to nesting birds. Historically, ferruginous hawks were known to use bison bones and dung in their nests for this purpose.
Here, the male takes a turn at incubating the eggs. Typically, the male will bring food to the nest while the female is incubating, and the female usually leaves to consume the prey while the male takes a turn with the eggs. In this pair, the male is identified by the paler grey head and relatively unmarked breast and belly, and by the smaller size when the birds are together at the nest.
this photo, you can just see the female’s first egg beneath her as she stands on the nest. You can also see the streaking on the breast and belly of the female compared to the white breast on the male.
The female will incubate the first egg but often doesn’t begin serious incubation until a few eggs are laid. Eggs hatch after about 32 days of incubation. With an egg being laid every other day, and the average clutch (the total number of eggs laid in a single nesting attempt) in our area being five eggs, you would expect 10 days for all the eggs to hatch once hatching begins. Typically, it’s actually about half that time because of delayed incubation. It’s thought that the staggered hatching results in at least some of the chicks surviving in years when prey is scarce; the older and larger chicks being more aggressive during feeding while the smaller chicks can’t compete for food.
Although both adults will hunt, it’s mostly the female that feeds the chicks, especially when they are just a few days old, as in the photo above. The female will generally stay with the chicks until they are old enough to be able to keep their body temperature within a normal range, known as thermoregulation. Until then, the female will brood them (sit on the chicks with them nestled against her brood patch; an area of bare skin that develops prior to incubation) if they are cold or stand and shade them (spread her feathers out like an umbrella over the chicks) if it is hot.
Here, there are four chicks in the nest bowl. Only three made it to fledging age, about 45 days old. One of these chicks is our hawk 264292!
Above, the female accepts a pocket gopher from the male. Pocket gophers were the largest and most common prey species brought to the nest in our observations.
While the female broods the chicks, the male delivers a deer mouse. This was the second most common prey species delivered.
In this photo, that’s not a stick in the female’s bill, circled in blue. As evidenced by the pale green color, the male has brought a snake, specifically a western racer, for the female to feed to the chicks. We also saw the female feeding a gopher snake to the chicks.
While the game cameras that we used to get the photos above functioned well through the early part of the breeding season, the data cards filled up with images before the chicks were old enough to fledge. Because ferruginous hawks can be very sensitive to disturbance, we didn’t revisit nests to change out data cards while they were still active.
WDFW scientists plan to continue to monitor nests this spring using cellular cameras with functionality to download and delete photos as the season goes on. We hope to identify other prey items and determine if prey distribution changes throughout the season. Because of the data cards, we missed prey deliveries during the warmest months, and snakes may prove to be an important food source as the nesting period progresses.
In the meantime, WDFW biologists will continue to monitor hawk 264292 as the winter wraps up and she moves on from Nebraska. Stay tuned for more tracking of her progress and nesting season updates.
