SFVAS’s Bird of the Month for September is the Cooper’s Hawk!
The Cooper’s Hawk (Accipiter cooperii) is a common sight across the San Fernando Valley. Sleek and crow-sized, this agile raptor is built for maneuvering at top speed through backyards, dense trees, and suburban canopies. Adults sport a classic blue-gray back, warm reddish barring across the chest, striking red eyes, and a distinct dark “cap” on their head, using their rounded wings and long, banded tail like a built-in rudder.
In Southern California, these adaptable hawks have thrived alongside urban sprawl. They are specialized bird hunters, often staking out backyard feeders, parks, and riparian corridors to ambush doves, starlings, and small mammals with sudden bursts of speed. During the spring breeding season, pairs build bulky stick nests tucked high in tall non-native eucalyptus, pine, or native oak trees, fiercely defending their territory while raising a brood of three to five chicks.
One remarkable fact about the Cooper’s Hawk is the extreme size difference between the sexes, known as **reversed sexual size dimorphism**, where females can be up to one-third larger than males. This size gap allows a mated pair to hunt entirely different prey sizes without competing against each other in the same home range.
