A female Cooper's Hawk took a Mourning Dove that had been peacefully feeding on a patio; prey in hand, the predator flew straight into a glass door. The door, facing south, was a good reflector at the time of sky -- the predator's mistake is understandable. The photo reveals the impact.

The Cooper's Hawk stood dazed on the patio for a few seconds, shook her head and flew into a nearby eucalyptus where she proceeded to dine on the dove. Peacefully.