By John V. Richardson Jr., PhD
Accipitridae Family; ITIS: 175350; IUCN: Least Concern
(J. F. Gmelin, 1788)
Description/Field Marks: “Brown body, heavy beak; distinctive red tail [from above]; whitish belly with dark streaks; dark bar on leading [trailing?] edge of underwing; juvenile has gray-brown tail” NG, p. 73.
Vocalizations: “Often a quite prolonged kee-ahrrr,” AS, p. 539. “Usually loud whistles or screams,” GB, p. 46. Variously described as harsh, hoarse, loud, or raspy.
Male/Female: Males “weigh 690 to 1300 grams (1.5 to 2.9 pounds)…while a female can weigh between 900 and 2000 grams (2 and 4.4 pounds)” according to Wikipedia. Courtship feeding. More than two may be called a boiling or spiraling of hawks.
Diet: Opportunistic carnivorous. Mostly rodents (probably 85% plus), rabbits, ferrets, lizards, and .
Courting Displays: Typically aerial. “Pair spiral, recross, male usually circling behind and above female. Male may stoop at female, feet touching or interlocking as female rolls over,” Birder’s Handbook, p. 232.
Nesting: Neat cup in cliffs or ground, but commonly “in crotch of large tree with commanding view; bulky, of sticks and twigs lined with inner bark strips, evergreen sprigs, green leaves; greens renewed. May use old raptor nest as base,” according to Birder’s Handbook, p. 232.
Eggs: commonly 2-3, but 1-4; white/bluish white, spotted with brown or unmarked” BH, p. 232. Great horned owls, the red tail's natural predator, eat eggs and nestlings.
Incubation: 28 or 30-35 days. Eyas, or the unfledged hawk, “Young batch asynchronously” HB, p. 232. “Natal care by both parents,” GB, p. 46. Fledging at 45 days.
Behavior: solitary and can sit for hours, “commonly sighted at roadsides, perching atop telephone poles, haystacks, or fence posts,” AS, p. 539. “Female often returns to previous nesting territory” BH, p. 232; in mid-morning, rides thermals with dihedral (windmills in diving)
Longevity: Females may live to be at least 27 years, 9 months according to "Old, but Unready to Be Rung Out," New York Times, 20 December 2010, p. A18.
Habitat/Local Sites: Ubiquitous in California deserts or grasslands--“open fields or rolling hills” ICB, p. 9; urban dweller up and down the I-405 (between Manchester and Wilshire Blvd. in Los Angeles).
Migration: Year round residents, but summer breeding may be in Canada and winters south to Panama. Some positive tests by the CDC for West Nile Virus in New York state in 2000 and Yakima County, Washington in 2007.
Range: Caribbean; North America to Central America (Panama).
Environmental Threats: Historically DDT, but now perhaps PBDE. “The parents may have fed the nestlings pigeons or rats that contained lethal levels of poison—a common cause of death for the delicate hawks;” see, Sewell Chan, “3 Baby Hawks Feared Dead After One’s Body Is Found,” New York Times 13 May 2008.
Did you Know: “It plays an important role in controlling rodent populations” AS, p. 539. Hollywood uses its cry to represent any eagle or hawk anywhere in the world. And, in May 2011, one can see a streaming video of Violet and Bobby as well as their eyas at http://www.livestream.com/nytnestcam
Audubon Society Field Guide to North America Birds, Western Region. Knopf, 1977.
Charles R. Preston, Red-Tailed Hawks. Wild Bird Guides Series. Stackpole Press, 2002.
National Geographic Field Guide to Birds, edited by Mel Baughman. NG, 2004.
Marie Winn, Red-tails in Love: A Wildlife Drama in Central Park. New York: Pantheon Books, 1998. –A delightful true-story of Pale Male and his mating efforts on a ledge of Mary Tyler Moore’s apartment building as told by a WSJ birding columnist.
FIELD NOTES: Seen at Big Morongo Canyon Preserve, Loop Trail, about 8:30AM on 3 May 2008 (cool; no breeze) and regularly at hotspots along the I-405 between Manchester Blvd. and Wilshire Blvd. (to be posted @ eBirds)
Updated: 18 May 2011.