The white-tailed hawk (Geranoaetus albicaudatus) is a large bird of prey species in the family Accipitridae, order Accipitriformes. It is found in tropical and subtropical environments throughout the Americas.
Taxonomy
The species was first described by French ornithologist Louis Jean Pierre Vieillot in 1816 under the protonym Buteo albicaudatus. It is currently classified within the genus Geranoaetus. Three subspecies are recognized:
- Geranoaetus albicaudatus hypospodius — found from coastal Texas and the Rio Grande Valley through Middle America to northern Colombia and western Venezuela
- Geranoaetus albicaudatus colonus — found from eastern Colombia to Suriname, south to the mouth of the Amazon River
- Geranoaetus albicaudatus albicaudatus — found from the southern Amazon rainforest to central Argentina
Distribution and Habitat
The white-tailed hawk occurs from the coast of Texas and the Rio Grande Valley south to central Argentina. Its range also includes several Caribbean islands in the Lesser Antilles and Trinidad and Tobago. It prefers open or semi-open regions up to approximately 600 meters (about 2,000 feet) above sea level, with few trees that might obstruct flight. The species is largely sedentary, though some populations may make regional movements when food is scarce. It generally favors arid habitats and rarely occurs in areas with heavy rainfall.
Description
The white-tailed hawk is a large, stocky hawk, similar in size to the Swainson's Hawk (Buteo swainsoni) and the Red-tailed Hawk (Buteo jamaicensis). It attains a total length of 44–60 cm (17–24 in) and a wingspan of 118–143 cm (46–56 in). Body mass ranges from approximately 865 to 1,240 g depending on the subspecies.
Adult birds are grey above and white below and on the rump, with faint pale grey or rufous barring. The short tail is white with a narrow black band near the end, which is conspicuous in flight. A rusty-red shoulder patch is characteristic when the bird is perched. The iris is hazel, the cere is pale green, the beak is black with a horn-colored base, and the feet are yellow with black talons.
Immature birds are darker than adults and may appear nearly black in poor light. The wing lining is conspicuously spotted black-and-white. The tail changes from brown with several dark bars to greyish with a hazy dark band as the bird approaches maturity.
Behavior and Ecology
Feeding
The white-tailed hawk's preferred hunting technique is to hover while scanning the surroundings for potential prey. Its diet varies by environment: rabbits make up the majority of the diet in southern Texas, while large lizards are preferred prey in the Dutch West Indies. Other prey includes cotton rats, snakes, frogs, arthropods (particularly grasshoppers, cicadas, and beetles), and small birds. It is also known to feed on carrion and to gather with other birds at brushfires to catch small animals fleeing the flames.
Reproduction
Breeding pairs construct nests from freshly broken twigs, often from thorny plants, typically placed 1.5–5 meters (5–15 ft) or more above the ground in a tree or yucca. One to three eggs (usually two) are laid per clutch. The eggs are white and often lightly spotted with brown or lavender. White-tailed hawks tend to reuse nest sites, and nests built up over years can reach up to 1 meter (3 ft) across.
Conservation Status
The white-tailed hawk has a wide geographic range and is not considered globally threatened. The IUCN Red List classifies it as Least Concern. According to BirdLife International, the species has an extensive extent of occurrence and its population trend is not considered to be undergoing a significant decline.
In the United States
In the United States, the white-tailed hawk is found in coastal and southeastern Texas, particularly in native prairie and grassland habitats. It is fairly common on the coastal prairie of Texas but is scarce in farm country and pastures. The Cornell Lab of Ornithology notes that the oldest recorded white-tailed hawk was a female at least 10 years and 7 months old when found in Texas.
Additional Notes
According to Birds of the World, the white-tailed hawk holds the widest latitudinal distribution of any Buteo-related species, spanning from approximately 29°N to 44°S. Despite this, it remains one of the least-studied North American raptors scientifically. The species' call is described as a high-pitched cackling "ke ke ke," with a tinkling quality.
