Survival depends on a surprise attack on an unsuspecting bird or mammal, one that has made the potentially fatal mistake of moving away from cover at the wrong moment. The Cooper’s may be perching in a hidden location, or coming in on a circuitous strike manuever. Experienced birds will make just a single try. A significant amount of energy has been expended at this point, and with the element of surprise spoiled, the hunt must start again from scratch. Ornithologists estimate that the hunting success rate for Cooper’s is 21 percent for birds and 53 percent for mammals. In the SW their diet is about half and half. These accipiters are widespread across the US, and quite common in Arizona. The long barred tail is your best clue for identification, and wings that are relatively short and rounded. Cooper’s rapid wing beats carry them swiftly on their stealthy flights, so keep your eyes peeled; maybe you too will be treated to a glimpse of one of these gorgeous birds.
The bird in this photo showed up in my sister’s back yard about this time last year. She lives in Oregon. Note the greyish eyes, an adult’s would be red.