By Lewis Young

The Sharp-shinned Hawk (Accipiter striatus) is a small, very agile hawk of the forest and woodlands. With a wingspan of 17-22 inches and a length of 10-14 inches, it displays an amazing ability to fly rapidly through dense trees and shrubs in pursuit of prey. Adults are a slatey blue-gray on the upper parts with narrow horizontal red-orange barring on the underparts. The tail is banded with a narrow white tip and the eye is red or orange. Juveniles differ from adults by having brown upper parts, mostly coarse vertical-streaked underparts, and yellow eyes. As with all Accipiters, when flying in the open, it has a distinctive pattern of several quick wingbeats followed by a glide.

It is the smallest of the 3 species of bird-hunting Accipiter hawks (Cooper’s Hawk and Northern Goshawk are the other two) and can be difficult to separate from the Cooper’s Hawk, which is the next largest, because their plumages are similar and size can be difficult to judge.

As in all Accipiters, the female is noticeably larger than the male; this can lead to confusion in identification. On flying birds, the Sharp-shinned’s head is smaller, the leading edge of the wings is more hunched and pushed forward and the wingbeats are deeper with more flicking “wrist action,” where the Cooper’s head is larger and the leading edge of the wings are straighter with wingbeats that are stiffer and shallower. The Sharp-shinned’s tail is more square-tipped and relatively shorter than the Cooper’s tail which is more rounded. On perched birds, the Sharp-shinned has a relatively smaller bill size and leg thickness than the Cooper’s, but these can be difficult to see.

Sharp-shinned Hawks live in and at the edges of mixed or coniferous forests and open deciduous woodlands. In the winter, they may be found in any kind of forest or brushy area but tend to avoid open country. Nests are a platform of sticks lined with bark strips, grass, and twigs and sometimes are built on top of an old crow or squirrel nest. The shallow, platform-like nest is usually 1–2 feet in diameter and 4–6 inches deep. Both sexes bring nest material, but the female may do most of the building. The nest site is very well concealed and usually in a dense conifer within the forest or a dense grove and 20-60 feet above the ground. In courtship, pairs circle above the forest while calling. The male may fly high and dive steeply into the forest. Usually 4-5 eggs are laid, then incubated mostly by the female for 30-35 days. The eggs are bluish-white fading to white and blotched and washed with brown. The male brings food to the female on the nest and may sit on the eggs while she eats. For the first 1-2 weeks after hatch, the female remains close to the young and feeds the nestlings prey that the male delivers. After about 3-4 weeks the young may move out of the nest onto nearby branches and can fly at 5-6 weeks.

The Sharp-shinned Hawk diet is predominantly small birds up to about robin size. It is also known to eat small numbers of rodents, bats, squirrels, lizards, frogs, snakes, and large insects. One hunting technique is to perch inside foliage and wait for small birds to approach, then burst out after them. Another technique is to fly rapidly through the trees, twisting and threading around obstacles, and take prey by surprise.

Sharp-shinned Hawks are found all across the U.S. and Canada where forests or woodlands are found. Most of them nesting in Canada and parts of the northern U.S. leave their breeding grounds and may winter in the rest of the continental United States or migrate as far as southern Central America. Sharp-shinned Hawks are found yearlong in the Flathead and northwest Montana, but the individual birds may be different between summer and winter due to the migration.

Although they are considered uncommon in all seasons in the Flathead, concentrations during migration often are large. At two sites in western Montana where concentrations of migrating raptors are counted, Sharp-shinned Hawks are recorded in large numbers. The Jewel Basin site in the Flathead has recorded 779-1142 per year from 2008-2012, and in the Bitterroot Valley, the MPG Ranch has recorded 377-591 birds per year over the last 3 years. Sharp-shinned Hawks are detected on Christmas Bird Counts with some regularity.

Like other raptors, Sharp-shinned Hawks suffered population breeding failure when the pesticide DDT was in use in North America. Some carry high levels of this pesticide in their bodies even today, probably because much of their songbird prey spends winters in South America, where DDT is still used. However, yearly migration counts indicate that populations are now stable or even increasing.

Sharp-shinned Hawks may be attracted to the birds at feeders and although the Cornell Laboratory of Ornithology says studies indicate a feeder doesn’t greatly increase a bird’s chance of being taken by a raptor, many bird watchers prefer to discourage this behavior. If a hawk begins to regularly hunt at a feeder, simply remove the feeder for a week or so and the hawk will move on and the songbirds return when the feeder goes back up.

As one of our yearlong residents, Sharp-shinned Hawks contribute to the variety of raptors in the Flathead and northwest Montana and play a role in the natural function of the forest and woodland ecosystems. Those folks who spend much time in the forest and woodlands or watching their bird feeder are likely to see these interesting hawks, although it may be a brief view. Whenever you see a Sharp-shinned Hawk flashing through trees, twisting and turning rapidly, consider it a privilege to have seen such an agile flyer in action.