Cooper's
Hawk, Accipiter cooperii
Cooper's are often hard to distinguish from the similar but smaller Sharp-shinned Hawk. Cooper's legs are
thicker, roughly pencil-thick vs. toothpick-thin in Sharp-shinned. The head is proportionately larger and
blocky-shaped on the Cooper's, with the eye smaller-looking and forward on the head; the head looks
smaller and rounded on the Sharpie, with the eye looking larger and further back. The outer tail feathers
of Cooper's are shorter than the inner, often producing a rounded look to the tail tip, while the Sharpie's
tail feathers are all the same length, hence typically a square tail tip.
Sharp-shinned Hawks are regular winter residents of our area, but Cooper's are year-round and much
more common in my experience, and I have many more pictures of them. The adult bird above was neither
the first or last of the species to pay a visit to our back yard fountain.
The image above is a digiscope, one of the earliest of my pictures still on this site.
Juvenile Cooper's often have thinner streaks down the breast than Sharp-shinned;
this feature is pronounced in the bird shown just below. The juvenile above has a
less distinctive breast pattern, but can be recognized as Cooper's by blocky head
shape, eye appearing smaller and more forward on the head than in a Sharpie,
the relatively thick leg, and the curved tail tip.
This juvenile Cooper's Hawk was being harassed by several American Crows, including the one shown out-of-focus here, and shortly after I took this photo, the hawk left this perch.
Above, a Cooper's nestling, nearly fledged but still with some tufts of down, at Arastradero Preserve in June 2007; below, another at virtually the same stage of development but standing out on a branch near the nest, in a residential yard in Cupertino, June 2009.
