Northern Harrier, Circus cyaneus, Attacks on Greater Sage-Grouse, Centerocercus urophasianus, in Southern Alberta

The Greater Sage-Grouse (Centrocercus urophasianus) is an endangered species in Canada, making it critical to understand all known causes of mortality. We report the first recorded observations of female Northern Harrier (Circus cyaneus) attacks on male Greater Sage-Grouse. Although no attacks were successful, our observations suggest that Northern Harriers are predators of Greater Sage-Grouse.