Red-shouldered hawks are medium-sized birds of prey found in North America. Adults have brownish heads, reddish chests, and pale bellies with reddish bars. Their tails are marked with narrow white bars. Red "shoulders" are visible when the birds are perched. These hawks' upperparts 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 flight style.
Red-shouldered hawks breed in eastern North America and along the coast of California and northern to northeastern-central Mexico. They are permanent residents throughout most of their range, though northern birds do migrate, mostly to central Mexico. Red-shouldered hawks are forest raptors. In the east, they live in bottomland hardwood stands, flooded deciduous swamps, and upland mixed deciduous conifer forests. They tend to live in stands with an open subcanopy, which makes hunting easier. They may also be found in some suburban areas where houses or other buildings are mixed into woodlands. In the west, they live in riparian and oak woodlands, and also in eucalyptus groves and some residential areas.
Red-shouldered hawks are short- to moderate-distance migrants; they typically migrate alone, although may sometimes form small flocks of three or more birds. While migrating, the birds try to avoid crossing large bodies of water. Red-shouldered hawks are solitary and very territorial. They hunt by day and search for prey while perched on a treetop or soaring over woodlands. When hawks spot prey, they kill it by dropping directly onto it from the air. They may cache food near their nest for later consumption. When in clearings, they sometimes fly low to surprise prey. Red-shouldered hawks, like most raptors, have very sharp vision and reasonably good hearing, with talons capable of killing animals at least equal to their own size. These birds use different calls to communicate with each other. The most common call sounds as 'kee-aah' and is used to defend the territory, and when the birds feel threatened.
Red-shouldered hawks are carnivores. They mainly feed on small mammals, especially rodents. These include voles, gophers, mice, moles, and chipmunks. Slightly larger mammals, such as rabbits and tree squirrels, are also occasionally preyed on. Other prey can include amphibians, reptiles (especially small snakes), birds, fish, and large insects.
Red-shouldered hawks are monogamous and pairs mate for life. Courtship displays occur on the breeding grounds, and involve soaring together in broad circles while calling, or soaring and diving toward one another. Males may also perform the "sky-dance" by soaring high in the air, and then making a series of steep dives, each followed by a wide spiral and rapid ascent. These courtship flights usually occur in the late morning and early afternoon. Red-shouldered hawks' mating season is between April and July and peaks between April and mid-June. They tend to nest in wooded areas that are often located near water. The breeding pair builds a stick nest in a major fork of a large tree. They often use the same nest year after year, refurbishing it annually with sticks in the spring. The clutch size is typically 3 to 4 blotchy-marked eggs, often brown to lavender in color. The incubation period can range from 28 to 33 days. The hatchlings, which weigh 35 g (1.2 oz) at first, are brooded almost constantly by the female for up to 40 days. The male usually spends more time hunting but will also incubate and brood occasionally. The young leave the nest at about 6 weeks of age but remain dependent on the parents until they are 17-19 weeks old. They may continue to roost near the nest site until the following breeding season and begin to breed at 1 or 2 years of age.
Prior to 1900, the Red-shouldered hawk was one of the most common North American raptors. Population densities have decreased greatly due to the clearing of mature forests (principally the wet hardwood forest they prefer) since that time. Additionally affecting the Red-shouldered hawk was the greater availability of firearms in the early 1900s, leading to unchecked hunting of this and all other raptor species until conservation laws took effect in the latter half of the 20th century. Today, human activity, including logging, poisoning from insecticides and industrial pollutants, continue to loom as threats to these beautiful birds. Before its use was outlawed in the United States, Red-shouldered hawks and other raptors suffered from DDT pesticide. The DDT would cause their eggs to have thin, breakable shells, reducing their ability to reproduce. Accidental encounters with power lines and automobiles also take a toll on hawks. In spite of these dangers, habitat loss remains the biggest threat to Red-shouldered hawks.
According to the Hawk Mountain Sanctuary resource, the total population size of the Red-shouldered hawk is estimated to be 100,000 birds. According to the All About Birds resource, the total breeding population of the species is around 1.1 million individuals. Overall, currently, Red-shouldered hawks are classified as Least Concern (LC) on the IUCN Red List and their numbers today are increasing.