White-tailed Hawk

White-tailed Hawk

Summary:

Profile White-tailed Hawk
[Authority] Vieillot, 1816 | [group] Kites, hawks and eagles | [order] ACCIPITRIFORMES | [family] Accipitridae | [latin] Buteo albicaudatus | [UK] White-tailed Hawk |

[Authority] Vieillot, 1816 | [group] Kites, hawks and eagles | [order] ACCIPITRIFORMES | [family] Accipitridae | [latin] Buteo albicaudatus | [UK] White-tailed Hawk | [FR] Buse a queue blanche | [DE] Weissschwanz-Bussard | [ES] Busardo Coliblanco | [NL] Witstaartbuizerd | copyright picture

copyright: R. Garrigues

Buteo albicaudatus hypospodius from Texas to northern Colombia and western Venezuela. The top and sides of the head and upper back are ash grey, the lower back and rump are white with wavy pale bars of grey or rufous. The tail is white, with a conspicuous black bar near its tip and some narrow faint grey cross-lines. There is a conspicuous rufous patch on the shoulders. The wings are black above, paler below, barred and marbled with grey near the bases of the primary flight feathers. Below the wings is white, with faint narrow, brownish bars on the sides and on the under-wing coverts. The thighs are very faintly barred. The eyes are hazel; the cere pale green; the bill black, horn-colour basally; and the legs yellow. Immatures are black, with conspicuous but variable amounts of white below; sometimes limited to a large patch on breast; sometimes extending down mid-abdomen, with flanks and under-tail coverts white. A suggestion of the chestnut shoulder patch of the adult is visible in some, perhaps older, individuals. Wing linings are conspicuously spotted black and white. The tail is brown with numerous darker bars; later it becomes more like that of the adult, but marbled greyish white and with an indistinct dark band. The eyes are light brown; the legs lemon yellow; the cere and bare facial skin pale greyish green. Buteo albicaudatus colonus from eastern Colombia to Surinam south of the range of the preceding and south to the mouth of the Amazon and including the Caribbean Islands. It is generally smaller and paler. There is also a dark phase, which is entirely ashy grey, except for the normal tail and barred under-tail coverts; sometimes with rufous marks on belly, thighs and shoulders. The immatures of the dark phase, are sometimes entirely black except the tail. Buteo albicaudatus albicaudatus in the southern part of range from southern Brazil south. A larger bird. The head and mantle are darker; the throat usually black except in western Argentina. There is also a dark phase present.

In southern Texas the White-tailed Hawk is most visible in its favoured haunts in the prairies near the coast, often where there are only scattered bushes, yuccas, or large cacti. It can be seen perched on bushes, trees, telephone poles, or even on the ground. It spends a lot of its time soaring. In other parts of its range its haunts are similar, but in some places it likes open hillsides, up to about 2,000 feet. It can also be found near clearings or roads within dry woodland. Although most often found in semi-arid areas and this is true also of the islands it inhabits in the southern Caribbean it may be seen in small numbers, in parts of the northern pampas of Argentina, which are very wet.
When the wind is favourable, the White-tailed Hawk resorts to hovering while hunting. It will pause in one spot for some time, either with wings motionless, sitting on updraughts, or waving the broad wings in a short arc. If nothing materialises it will glide on for some distance and pull up into the wind again to repeat the process. This type of hunting is well adapted to dry grassy hillsides.

The White-tailed Hawk (Buteo albicaudatus) is a tropical and sub-tropical species ranging from southern Texas to central Argentina; also some of the islands of the southern Caribbean. It preferred range includes open, semi-open or thinly forested country, whether flat or hilly. Its range includes parts of Colombia, Ecuador and eastern Bolivia, as well as Uruguay and Paraguay, stopping at the northern border of Patagonia. The species is not migratory at the northern extremity of its range in Texas, but probably is further south. In Suriname pairs can be sen flying over sandy savannas and the coastal areas with scattered trees near Nickerie.

In southern Texas, where rabbits are abundant, White-tailed Hawks feed upon them extensively, although not exclusively. It has also been known to take cotton rats, snakes, lizards, frogs, grasshoppers, cicadas, and beetles, and occasionally a quail or other bird. In the Dutch West Indies it appears to specialise in lizards of various sizes, but predominantly species of over 30 centimetres in length. It is also known to take young chickens and occasionally carrion.


This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence 30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern. [conservation status from birdlife.org]


This buteo builds a large nest of freshly broken twigs, often thorny ones, mixed with bunches of dry grass and lined with finer material, among which are some green sprays of mesquite or other plants. The nest is added to each year and may become quite large, measuring almost three feet across. On the Texas prairies large bushes or small trees may be few and far between, and often the nest occupies the only growth in miles and is visible from a long distance. Here the nest is usually only five to fifteen feet from the ground or even lower. They do, however, like a nest site on a slight ridge with a view in all directions. When the nest is approached the incubating bird leaves at a considerable distance, and the pair may soar or hover high overhead, sometimes silent, sometimes screaming, or go off altogether. Two eggs are usually laid, but often only one and sometimes three. The young flegde after about seven weeks.

Poorly known. Presumably sedentary over most of tropical range. Northernmost birds are not migratory, but populations further South in North America may be; reported migration may refer to irruptive movements in response to population declined of prey species.

Specification

  1. Measurements
  2. spanwidth min.: 120 cm
  3. spanwidth max.: 135 cm
  4. size min.: 57 cm
  5. size max.: 60 cm
  6. Breeding
  7. incubation min.: 29 days
  8. incubation max.: 31 days
  9. fledging min.: 47 days
  10. fledging max.: 31 days
  11. broods 1
  12. eggs min.: 1
  13. eggs max.: 3
  14. Conservation Status
  15. White-tailed Hawk status Least Concern

Subspecies

  1. Buteo albicaudatus albicaudatus
  2. s South America
  3. Buteo albicaudatus colonus
  4. Netherlands Antilles, n South America
  5. Buteo albicaudatus hypospodius
  6. s Texas (USA) to n Colombia and nw Venezuela
  7. Buteo albicaudatus
  8. NA, LA sw USA to c Argentina
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