In June of 2023, Washington Department of Fish and Wildlife (WDFW) biologists in southeast Washington banded three broods of endangered ferruginous hawk nestlings in the Wallula Gap and Starbuck areas. That effort, and the work involved in reaching hawk chicks in a platform nest, was documented in a prior WDFW blog post. All the fledglings (young birds that have recently learned to fly but are still dependent upon their parents) had bands placed around one leg and the largest female chick from each brood was fitted with a transmitter. The plan was that biologists would use the transmitters to track the birds’ movements.
Unfortunately, we were not able to learn much from those birds as, not long after the banding, they both met with an early demise, most likely killed by a coyote or bobcat.
“This is not unusual for this species,” said WDFW Research Scientist Jim Watson, who specializes in raptor studies. “Ferruginous hawks experience a very high rate of mortality of their young.”
These hawks are endangered in Washington because of predations like these but also due to bigger threats like the loss and fragmentation of shrubsteppe and grassland habitat on which these birds rely. Many areas that were previously natural have been converted to agriculture and residential development, leaving less and less habitat for wildlife. A secondary impact of this is declines in the number of the hawk’s primary prey- jackrabbits and ground squirrels- also caused by habitat loss. Other common sources of mortality for these hawks include illegal shooting, electrocution from powerlines, and collisions with wind turbines.
Fortunately, biologists have learned to be adaptable when it comes to the unpredictability of wildlife. So, it was back up the ladder to fit a third bird with a transmitter to replace the ones that were killed. And what a bird the newly outfitted one turned out to be! According to its’ transmitter, this bird put on some major miles almost as soon as it left the nest.
Transmitters are an important part of learning about bird species. They are very small, approximately 30 grams or the weight of about 12 stacked pennies so they don’t impede the movement of the bird wearing it. They are commonly used in studies around the world to help biologists understand a bird species’ long-term range use and how fledged juvenile birds use the landscape, both in Washington and at dispersal and wintering areas across the western United States.
“Identifying these use areas is important for protection of the species, particularly in light of wind power and other potential development,” said Mark Vekasy, WDFW assistant district wildlife biologist in southeast Washington
While WDFW doesn’t generally name animals involved in studies to avoid anthropomorphizing them (attributing human characteristics or behavior to them), this bird was informally nicknamed “Delaney” for ease in identifying her. That’s because she was hatched near the grain elevators at Delaney in Columbia County. For several years now, her parents have been inhabiting any one of multiple cliff nest sites above the Tucannon River.
As soon as she fledged from that family nest, Delaney started racking up flight miles. From soon after she was banded through early October of 2023, she logged about 4,000–4,500 miles of flight, averaging travel of about 41 miles per day by air.
Vekasy and Watson have been capturing birds in the area for many years for research purposes and both say this bird was an overachiever when it came to travel.
“This is the first bird we have encountered that has dispersed as far north as the mountains around Banff and Jasper in British Columbia,” said Vekasy.
After checking out that area in September, she headed for warmer climates.
“I think this is only the second juvenile we’ve ever radioed in Washington that went through Mexico,” said Watson. “This bird is pretty amazing.”
From Mexico, Delaney continued west to the Gulf of California, then north to southern California.
“It was a little early for her to be in California in October for winter compared to previous birds we’ve observed,” said Watson. “I’m guessing she was following other hawks headed the same direction.”
Watson and Vekasy figured she was heading to Bakersfield or Sacramento, both good wintering areas for hawks and on the southerly end of the Pacific Flyway migratory route. The area also has seasonal marshes that provide water and attract prey to the area that hawks depend on.
The area also has many wind turbines, which biologists are always concerned could be fatal to their transmitter-outfitted birds. Delaney managed to avoid them but unfortunately could not avoid the perils of migration and became victim to an unknown predator or starved due to lack of prey.
“Unfortunately, she went down 60 miles east of San Bernadino, California on October 10,” said Watson. “She was probably only a few miles from the area where we would have expected her to winter this year.”
Migration consumes a lot of energy and first-year birds are challenged in that they’re not only learning how to hunt but don’t have a previous knowledge of where to hunt. As in this case, this can be disastrous.
With help from the Marine Corps Air Ground Combat Center Office of Environmental Affairs in the area, the biologists were able to recover her remains and transmitter.
“In spite of her short life, she provided considerable information on first-year movements, especially from hawks fledged in Washington,” said Watson.