This bird is sometimes reported to be at large in Western Europe, especially Britain, but it is a popular species in falconry and these records almost invariably all refer to escapes from captivity.

[3] John James Audubon gave this bird its English name in honor of his ornithological companion, financial supporter, and friend Edward Harris.

Harris's hawks' social nature has been attributed to their intelligence, which makes them easy to train and has made them a popular bird for use in falconry.

[14] The juvenile Harris's hawk is mostly streaked with buff and appears much lighter than the dark adults.

In his Catalogue of Birds in the British Museum, Sharpe gives an extensive synonymy, with various authors having earlier placed harrisii in three genera and unicinctus in eleven.

[22] The wild Harris's hawk population is declining due to habitat loss; however, under some circumstances, they have been known to move into developed areas.

Nests are known to be predated by coyotes (Canis latrans), golden eagles (Aquila chrysaetos), red-tailed hawks (Buteo jamaicensis), great horned owls (Bubo virginianus), and flocks of common ravens (Corvus corax), predators possibly too formidable to be fully displaced by Harris's hawk's cooperative nest defenses.

[30] The majority of Harris's hawks' prey are mammals, including ground squirrels, rabbits, and larger black-tailed jackrabbits (Lepus californicus).

[32][33][34] In one instance, a lone Harris's hawk successfully killed a subadult great blue heron (Ardea herodias).

[39][40][41][42][43] In the Southwestern United States, the most common prey species (in descending order of prevalence) are desert cottontail (Sylvilagus auduboni), eastern cottontail (Sylvilagus floridanus), black-tailed jackrabbit (Lepus californicus), ground squirrels (Ammospermophilus spp.

), Gambel's quail (Callipepla gambelii), scaled quail (C. squamata), northern bobwhite (Colinus virginianus), cactus wren (Campylorhynchus brunneicapillus), northern mockingbird (Mimus polyglottos), desert spiny lizards (Sceloporus magister), and skinks (Eumeces spp.

)[44][45] In the tropics, Harris's hawks have adapted to taking prey of several varieties, including those like chickens and European rabbits introduced by man.

[48] While most raptors are solitary, only coming together for breeding and migration, Harris's hawks will hunt in cooperative groups of two to six.

[51] Trained Harris's hawks have been used to remove an unwanted pigeon population from London's Trafalgar Square,[citation needed] and from the tennis courts at Wimbledon.

The original watercolor by Audubon was purchased by the New York History Society where it remains to this day (January 2009).