Deal, of the raptor conservancy, knows of at least three Cooper's hawk nests where young birds died in Seattle during the heat wave, including three downy hawks found in a crumpled heap beneath a nest in southeast Seattle's Cheasty Greenspace.
He suspects the heat wave affected at least two more failed nests in Seattle, which has more than 60 nests overall.
The heat wave's impacts were widespread. The Portland Audubon Society said it had admitted more than 100 Cooper's hawks to its wildlife care center. And the Sarvey Wildlife Center in Arlington cared for dozens of dehydrated or injured swallows.
" ... Over 50 in a couple days. That was crazy to get in that many birds at one time," said Jessica Paolello, Sarvey's clinic manager, who had to stock up on supplies — ordering 150,000 extra mealworms — to ensure the birds remained well-fed during their stay.
Extreme heat affects birds much as it does humans.
Birds' normal body temperatures range from about 104 to 110 degrees, according to Blair Wolf, a professor of biology at the University of New Mexico.
When body temperatures climb too high, birds must evaporate water to cool down. They often do so by panting, though some can lose water across their skin.
When heat exceeds birds' normal body temperatures, avian eggs can overheat and fail, said Steven Beissinger, an ornithologist and professor of ecology and conservation biology at the University of California, Berkeley.
Beissinger, who has studied birds in the Mojave Desert, said parents will often stand over nests to provide shade or fly great distances to wet their wings to cool eggs. Beissinger suspects birds here might not have developed such responses to heat.