Alameda is hosting at least one family of Cooper’s hawks (named for naturalist William Cooper) this year. In late June, Alaina Onesko, the Alameda Police Department’s sole animal control officer, rescued a young Cooper’s hawk that had gotten stuck in sap in a tree on Buena Vista Avenue.
One of three accipiters in California, Cooper’s hawks (Accipiter cooperii) are often described as crow-sized. The Peterson Field Guide to Birds of North America describes them as, “A short-winged, long-tailed hawk; averaging not quite so large as a crow.”
And speaking of crows, keep your eyes peeled, as crows often mob Cooper’s hawks, which can reveal the location of the hawk and provide a good opportunity for size comparison. Don’t get frustrated if you can’t immediately differentiate a Cooper’s hawk from a sharp-shinned hawk, they are notoriously difficult to tell apart.
Of the two accipiters found in Alameda, the Cooper’s hawk is the most common and likely the accipiter that just flew by. It is very exciting to see these aerial acrobats in action. They will even run along a tree branch to get into a better launch position for their next attack. Think of them as ambush predators. Cooper’s do well in urban settings as long as there is sufficient wooded habitat. These are not a typical species of open country but can be found nearby if the perimeter offers some bushy cover. For instance, I often find them at Merced National Wildlife Refuge in trees or heavy vegetation but not out in the open the way one sees harriers or red-tailed hawks patrolling wetlands and grasslands. Crab Cove in Alameda is a great spot to see Cooper’s hawks. And in the tree lined areas of Corica Park golf course. Check out the surrounding trees, fence posts, and grassy areas at Martin Luther King Shoreline. In the last month I’ve seen them take ground squirrels and fly into the brush that grows along the fence of the New Marsh area.
In July of 2021, at Chochenyo Park, there were 4 juveniles sighted bathing in a puddle of water. Later, they were observed in the backyards of the surrounding houses using both trees and human structures as roosting and eating sites. During 4 weeks of observing the Chochenyo family I witnessed only birds being taken & eaten. Several times they attempted to take ground squirrels but were not successful. They eat mostly birds but are known to prey on mammals, reptiles, and insects.
Although infrequently, Cooper’s hawks can be seen hunting the shoreline at Elsie Roemer Bird Sanctuary. Look for them perched on top of the light poles along Shoreline Drive or flying parallel to the shore scanning for potential prey. In April 2023, while we were watching the bald eagles at Elsie Roemer, a Cooper’s hawk flew in and took a least sandpiper just as the eagles were returning to Corica Park. What a dramatic day!
Alameda Point is known for osprey, peregrine falcons, and least terns, but Cooper’s hawks are also found there. For several years there have been Cooper’s found along West Midway Avenue near Alameda City Hall West.
The Sibley Guide to Birds describes the Cooper’s hawk as 16.5 inches long with a wingspan of 31 inches, weighing in at just under a pound. Cooper’s hawks are found throughout North America and are considered monogamous. Standard clutch is two to five eggs. Laying begins late April to May and the young fledge in four to five weeks, so the bird Officer Onesko rescued had likely been flying only a few weeks. They remain in the area of the nest and interact as a family group for several more weeks after fledging. The family of four juveniles I observed at Chochenyo Park continued to frequently interact with one another after leaving the nest. The adults were largely absent.
These dramatic and entertaining hawks, like all raptors, are susceptible to chemicals and pesticides. And since they literally live among us, it is imperative that we exercise environmental best practices and strive to create and sustain suitable neighborhoods that are favorable to people, birds, mammals, and insects. The Bay Area is home, haven, and host to a multitude of species and ecosystems.
Rick Lewis is a long-time member of the Golden Gate Bird Alliance (GGBA) and other environmental organizations. He contributes often to Bay Area and Central Valley birding groups that promote wildlife and habitat conservation.
This article is part of a series written by Friends of the Alameda Wildlife Reserve (FAWR) members, FAWR is a Conservation Committee of Golden Gate Bird Alliance (formerly Audubon). To find out more about birds and GGBA’s free guided trips visit the Golden Gate Bird Alliance website.
