More severe wildfires may decrease northern goshawk habitat

As wildfires become more intense and frequent in the western United States, northern goshawks may be losing important landscapes they rely on in California’s Plumas National Forest.

“California spotted owls are the Beyoncé of birds, so no one has to justify studying them,” said Rachel Blakey, a postdoctoral fellow at The Institute for Bird Populations and UCLA La Kretz Center for California Conservation Sciences. “I think northern goshawks are interesting even though quite a lot of people know very little about them. There are birds out there in forest prone to megafires, and we really need to know about how they’re using the landscape and how vulnerable they are.”

In collaboration with the U.S. Forest Service and the University of Missouri, Blakey led a study published in Biological Conservation looking at how the diurnal predatory bird uses the burned forest stands during the day when they’re foraging and at night when they’re roosting. They’re a top predator in the late-seral coniferous forest, Blakey said, but the team didn’t yet have a handle on how they respond to fire.

Rachel Blakey’s co-authors Colin Dillingham and Jeff Kidd band a northern goshawk before release. Courtesy Colin Dillingham

Blakey and her colleagues captured and fitted GPS loggers onto the cryptic goshawks to learn more about what types of landscape they were using. The loggers used tiny solar panels so they lasted longer and showed a longer view of the species’ lifecycle.

The team found that, as expected, the birds roosted in late seral forests, including large trees with high canopy cover, and they avoided burned areas. “There were almost no roosts in burned areas at all,” she said. In terms of foraging, the northern goshawks (Accipiter gentilis) selected late seral forests again, but the researchers were surprised to find more variability in habitat use at finer scales, including areas of forest dominated by smaller trees.

At every scale they looked at, though, the birds stayed away from areas that had experienced high-severity fires. “They seemed to be really avoiding these areas,” Blakey said, although they did enter areas that had been less severely burned.

“The message isn’t fire is all bad and needs to be stopped,” she said. “There’s a balancing act to do there.”

With climate change likely to increase extreme wildfires, that will likely affect these northern goshawks, Blakey said. Her team overlaid the areas the Plumas National Forest population uses with a wildlife hazard potential map and found that over 80% of their preferred areas were at high risk of large, stand-replacing fires. In all of the Sierra Nevada, 48% of the area is at high risk of fire that would be difficult to contain.

“We need to think really hard about what this will look like into the future,” she said.

Header Image: Northern goshawks in Plumas National Forest prefer unburned areas for roosting and foraging.
©Zweer de Bruin