Sharp-shinned Hawks are the smallest hawk in North America (males). They are regular visitors to winter backyard bird feeders, but not to feed on millet or sunflower, but to prey on the attracted songbirds. "Sharpies" as often referred, are strictly bird eaters, preying on birds up to the size of a dove or quail. They are agile enough to chase songbirds through the most tangled thickets and reappear unscathed. Sharp-shinneds nest in secluded, coniferous woodlands, but winter in edge habitat and suburban areas.
Sharp-shinned Hawks winter primarily from the US-Canadian border to Central America. They breed from May through August from Alaska through Canada, south into the Lower 48 but absent in the southern U.S.. They are fairly common across most of the Lower 48 during migration, especially at raptor migration hotspots, but are rarely encountered during summer. Recent migration counts at many sites show a general decline, but count numbers are difficult to assess due to many variables. When courting, they give a repeated, descending "kil, kil, kil, kil, kil," also a series of high-pitched "chirps" when agitated.
(Map from Cornell Lab of Ornithology's All About Birds. For dynamic distribution maps, visit the eBird website.)