Urban Cooper’s hawks face a range of threats

Collisions with windows are a leading cause of death for urban raptors in New Mexico, researchers found. But the biologists also uncovered another troubling cause of death. Humans had intentionally killed eight tagged hawks, some of which were bludgeoned to death.

Over 11 years, TWS member Brian Millsap and his colleagues at the U.S. Fish and Wildlife Service fitted Cooper’s hawks (Accipiter cooperii) in Albuquerque with GPS transmitters. When the birds died, researchers were able to determine what caused their deaths.

In a study published in the Journal of Raptor Research, the team looked at causes of deaths for female raptors in their first year, when the birds are more vulnerable, and after their first year.

Mortality was highest in the first four months of independence, researchers found. Regardless of age, disputes over territory or mates were the leading cause of death. Collision deaths were also high, but Millsap was surprised how many hawks were intentionally killed.

“I, like many others, had been falsely thinking that the days of rampant hawk shooting the U.S were behind us, but we are learning that is not the case.”

Read the study here.