The red-shouldered hawk (Buteo lineatus) is a medium-sized hawk. Its breeding range spans eastern North America and along the coast of California and northern to northeastern-central Mexico. Red-shouldered hawks are permanent residents throughout most of their range, though northern birds do migrate, mostly to central Mexico. The main conservation threat to the widespread species is deforestation.
Males are 38 to 58 cm (15 to 23 in) long and weigh on average 550 g (1.21 lb). Females are slightly larger at 47 to 61 cm (19 to 24 in) in length and a mean weight of 700 g (1.5 lb). The wingspan can range from 90 to 127 cm (35 to 50 in). Adult birds can vary in mass from 460 to 930 g (1.01 to 2.05 lb). Among standard measurements, the wing bone is 28–35 cm (11–14 in) long, the tail is 16–24 cm (6.3–9.4 in) long and the tarsus is 7.5–9 cm (3.0–3.5 in). Adults have brownish heads, reddish chests, and pale bellies with reddish bars. Their tails, which are quite long by Buteo standards, are marked with narrow white bars. Red "shoulders" are visible when the birds are perched. These hawks' upper parts are dark with pale spots and they have long yellow legs. Western birds may appear more red, while Florida birds are generally paler. The wings of adults are more heavily barred on the upper side. Juvenile red-shouldered hawks are most likely to be confused with juvenile Broad-winged Hawks, but can be distinguished by their long tails, crescent-like wing markings, and a more flapping, Accipiter-like flight style. In direct comparison, it is typically larger and longer proportioned than the Broad-wing, though is slightly smaller and more slender than most other common North American Buteos. This bird is sometimes also confused with the widespread Red-tailed Hawk. That species is larger and bulkier, with more even-sized, broad wings and is paler underneath, with a reddish tail often apparent. The Red-tail is also more likely to soar steadily, with wings in a slight dihedral.