Red-tailed Hawk
Description
The red-tailed hawk (Buteo jamaicensis) is a bird of prey that breeds throughout most of North America, from the interior of Alaska and northern Canada to as far south as Panama and the West Indies. It is one of the most common members within the genus of Buteo in North America or worldwide. The red-tailed hawk is one of three species colloquially known in the United States as the "chickenhawk", though it rarely preys on standard-sized chickens. The bird is sometimes also referred to as the red-tail for short, when the meaning is clear in context. Red-tailed hawks can acclimate to all the biomes within their range, occurring on the edges of non-ideal habitats such as dense forests and sandy deserts. The red-tailed hawk occupies a wide range of habitats and altitudes, including deserts, grasslands, coniferous and deciduous forests, agricultural fields, and urban areas. Its latitudinal limits fall around the tree line in the Arctic and the species is absent from the high Arctic. It is legally protected in Canada, Mexico, and the United States by the Migratory Bird Treaty Act.
Red-tailed hawk plumage can be variable, depending on the subspecies and the region. These color variations are morphs, and are not related to molting. The western North American population, B. j. calurus, is the most variable subspecies and has three main color morphs: light, dark, and intermediate or rufous. The dark and intermediate morphs constitute 10–20_ of the population in the Western United States, but seem to constitute only 1–2_ of B. j. calurus in western Canada.[28][29] A whitish underbelly with a dark brown band across the belly, formed by horizontal streaks in feather patterning, is present in most color variations. This feature is variable in eastern hawks and generally absent in some light subspecies (i.e. B. j. fuertesi). Most adult red-tails have a dark-brown nape and upper head, which gives them a somewhat hooded appearance, while the throat can variably present a lighter brown "necklace". Especially in younger birds, the underside may be otherwise covered with dark-brown spotting, and some adults may too manifest this stippling. The back is usually a slightly darker brown than elsewhere with paler scapular feathers, ranging from tawny to white, forming a variable imperfect "V" on the back. The tail of most adults, which gives this species its name, is rufous brick-red above with a variably sized, black subterminal band and generally appears light buff-orange from below. In comparison, the typical pale immatures (i.e. less than two years old) typically have a mildly paler headed and tend to show a darker back than adults with more apparent pale wing-feather edges above (for descriptions of dark morph juveniles from B. j. calurus, which is also generally apt for description of rare dark morphs of other races, see under that subspecies description). In immature red-tailed hawks of all morphs, the tail is a light brown above with numerous small dark brown bars of roughly equal width, but these tend to be much broader on dark morph birds. Even in young red-tails, the tail may be a somewhat rufous tinge of brown.[30] The bill is relatively short and dark, in the hooked shape characteristic of raptors, and the head can sometimes appear small in size against the thick body frame. The cere, the legs, and the feet of the red-tailed hawk are all yellow, as is the color of bare parts in many accipitrids of different lineages.[31] Immature birds can be readily identified at close range by their yellowish irises. As the bird attains full maturity over the course of 3–4 years, the iris slowly darkens into a reddish-brown, which is the adult eye-color in all races.[30] Seen in flight, adults usually have dark brown along the lower edge of the wings, against a mostly pale wing, which bares light brownish barring. Individually, the underwing coverts can range from all dark to off-whitish (most often more heavily streaked with brown) which contrasts with a distinctive black patagium marking. The wing coloring of adults and immatures is similar but for typical pale morph immatures having somewhat heavier brownish markings.[27]
Distribution & Habitat
The Red-tailed Hawk occurs from North America through Central
America including the Caribbean
(Raffaele and others 1998, Root
1988). It is widespread and fairly
abundant throughout Puerto
Ricos mainland, but it is most
numerous in the mountains
(Biaggi 1997, Bond 1961, Rivera-
Milán 1995b, Santana and Temple
1988). It is also known to inhabit
satellite islands such as Desecheo
(Meier and others 1989), Culebra
(Wetmore 1917), and Vieques
(Sorrié 1975, Wetmore 1916), in
the latter being a fairly common
resident (Gemmill 2015). This
species generally occurs on all habitats at all elevations
including towns and urban
areas (Oberle 2018, Raffaele and
others 1998, Rivera-Milán 1995b,
Santana and Temple 1988). The
atlas fieldwork yielded a total of
646 records within 355 hexagons
or 74 percent of the 479 total
hexagons (see map). Of the 355
hexagons where this species was
found, breeding met the atlas
definition of confirmed in 29
percent (102) of the hexagons,
probable in 23 percent (83), and
possible in 48 percent (169),
while it was observed in an
additional hexagon (<1 percent)
but without evidence of breeding
(see map). Red-tailed Hawk distribution. The map shows the highest breeding code by hexagon and overlaying the ecological life zones in
Puerto Rico. Note: percentages may not total 100 due to rounding. 173Red-tailed Hawk/Guaraguao Colirrojo
Breeding Habits
The Red-tailed Hawk builds a
large and bulky nest made of
sticks, which is usually placed
high in a tree or on the side
of a cliff (Santana and Temple
1988, Santana and others
1986). Previously published
reports indicate that it breeds
from January to July (Raffaele
and others 1998), but Santana
and Temple (1988) describe a
November-to-August breeding
period. Overall, the breeding
activity peaks in June, and
it mostly takes place in the
subtropical moist forest life
zone, which is consistent with
survey results of Rivera-Milán
(1995b). Atlas results show that this species breeding season
extends throughout the year
with the most breeding activity
from March to June (see chart).
Results show that this species
breeds throughout the island but
mostly within the subtropical
moist forest life zone (58 percent
of the hexagons) (see table
and map). It also breeds in
the subtropical wet and lower
montane wet forest life zones,
and subtropical rain forest life
zones at higher elevations (23
percent and 1 percent of the
hexagons, respectively), and in
the subtropical dry forest life
zone as well (18 percent of the
hexagons) (see table and map).
Conservation
The current population trend of the Red-tailed Hawk is described
as increasing (Butcher and
Niven 2007). This species is
currently listed as a species
of least concern by the IUCN
(BirdLife International 2016).
Locally, this species is not
listed in any of the threatened
categories of PRDNER and
USFWS. In Puerto Rico, the
Red-tailed Hawk has a protected
habitat in land of 12 percent or
992 km2 of the total area covered by the hexagons where evidence
of breeding was found for this
species (8466 km2).
Related Species
Family:
hawk