Red-shouldered Hawk

Red-Tailed Hawk_LeonidR_2Jan2011
The predatory superiority of the hawk over its defenseless quarry is the epitome of assault to the extent that ‘hawk’ and ‘war-like’ are synonymous


Common Name: Red-shouldered Hawk – The most distinguishing feature of this hawk species is the rufous coloration of the feathers at the upper part of the wing. The Red-tailed Hawk has red tail feathers.

Scientific Name: Buteo lineatus – The generic name is Latin for a hawk or a falcon; the two birds were not distinguished as separate species in early cultures. The species name refers to the presence of darker bands of breast feathers on a background of whiter feathers. Lineatus means ‘lined.’ The Red-tailed Hawk is B. jamaicensus, first identified in Jamaica.

Potpourri:  The Red-shouldered hawk is one of the two most common and virtually indistinguishable members of the order Falconiformes, commonly called raptors, which one routinely encounters in both open fields and sylvan habitats. The other is the Red-tailed hawk (Buteo jamaicensus). Distinguishing the two is complicated by the fact that there are at least five recognized subspecies of Red-shouldered hawk and fourteen of Red-tailed hawk, all based on variations in plumage coloration. The one obvious and descriptive difference is that the former has (more or less) red plumage on the upper wing, and the latter has a red tail. However, when encountered in the field, they are virtually impossible to distinguish.

A more reliable discriminator between the two is the habitat in which they are encountered; this in turn affects flight characteristics according to the practicalities of the terrain. Red-shouldered hawks are found in predominantly wooded areas near water. Their flight is characterized as “accipiter-like,” consisting of three or four rapid and shallow beats between short glide periods. This would be necessary in order to navigate through dense foliage and around trees; they also have longer and narrower tails than their red- tailed cousins attributable to a need for quick maneuvers in and around trees. The Red-tailed hawk is a denizen predator of the open fields and accordingly has a more stately flight pattern characterized by slow and determinant beats of the wing. This is an energy conservation measure necessary to allow for soaring over open ground in search of prey; their wings are often held in a slight dihedral V shape to promote aerodynamic equilibrium. The bottom line is that if you see a hawk perched on an isolated tree in otherwise expansive grassland, or, more typically, on a roadside power line or utility pole, it is almost certainly a Red-tailed hawk; if you see it in a wooded area, it is a Red-shouldered hawk.

There are other differences between the two species that warrant some discussion as a means to greater understanding of the raptor’s perspective. The Red-tailed hawk is significantly larger than the Red-shouldered hawk (similar to the difference between the raven and the crow), though you would not notice this unless they were adjacently collocated. A nominal adult Red-tailed hawk is about twice the size of a coeval Red-shouldered hawk and has a wingspan that is about a foot longer. Sexual dimorphism is evident in both species; the female is about 25 percent larger than the male. The speciated size differential is manifest in the interaction between the two when boundaries overlap, such as at the edge of a woodland; the Red-tailed hawk is dominant in this interaction according to the physics of girth. One behavioral anomaly that has been observed to offset this advantage concerns crows; Red-shouldered hawks live peaceably with and collaborate with crows in mobbing the larger Red-tailed hawks in the establishment of territorial boundaries. A second notable difference is audible; the two species have distinctive and different vocalizations. In the lexicon that only avian aficionados (aka birders) seem to comprehend, the National Geographic Complete Birds of North America offers that the Red-shouldered hawk has a “loud, repeated KEE-ahh, often repeated in groups of 8 – 10 repetitions,” whereas the Red-tailed hawk has a “husky scream, rising then dropping in pitch shee-eeee-arrr.” I would offer the opinion that applying human phonetics to animal sounds is at best a proximate characterization.

In many other ways, the Red-shouldered and Red-tailed hawks have essentially equivalent attributes, not surprising as they are closely related members of the same order, either Accipitridae or Falconiformes, depending on the source; the order includes eagles, buzzards, harriers, kites, and Old World vulture in addition to hawks. The root word accipiter is, like buteo, a Latin word for hawk; accipiter is thought to have a more folksy etymology in being derived from the Old Latin acupeter, which meant ‘fast flyer.’ The convoluted taxonomy of Accipitridae is confused by a number of anomalies; there is a genus Accipiter that is comprised of three species of smaller, bird-catching hawks (the common names are Northern goshawk, Sharp-shinned hawk, and Cooper’s hawk); buzzard is a (mostly British) alternative common name for the European hawk (B. buteo); and the Old World vulture is the Eurasian black vulture, not to be confused with the New World vultures in the Cathartidea Family (the Black vulture and the Turkey vulture). The word ‘hawk’ itself contributes to the confusion of the raptors. Webster’s New World Dictionary defines hawk as “any of various accipitrine birds having short, rounded wings and a long tail and legs, as Cooper’s hawk” which is an accipiter and not a (buteo) hawk. However, according to Webster’s New International Dictionary, a hawk is “any of numerous diurnal birds of prey belonging to the suborder Falcones of the order Falconiformes” which could include any birds in the order. For clarity, it is accordingly better to refer to the “hawks” as the buteo hawks.

Red-Tailed Hawk Juvenille_Columbia_Oct2010
Red-shouldered hawks are found in predominantly wooded areas near water where they hunt

The familial life-cycle oriented behaviors of the Red-shoulder and Red-tailed (buteo) hawks are quite similar. Starting in an aerie near the top of a tree or on a cliff edge, the fledgling hawk is hatched along with one and possibly two cohorts, depending on the availability of prey. As a counterpoint to the ferocity of the adult hawk, the eyas (the name given a nestling hawk which is derived from the Middle French niais meaning ‘from the nest’) is altricial; it must be carefully nurtured due its weak, defenseless condition. The female of the male-female parental pair normally tends to the nest, the male providing the food. After about three months, the eyas becomes a juvenile hawk, with inchoate dappled plumage, but large enough to set out on its own in search of prey and a mate.

The predatory superiority of the hawk over its defenseless quarry is the epitome of assault to the extent that ‘hawk’ and ‘war-like’ are synonymous. Few acts of violence in nature compare to the Gadarene plunge of the avian destroyer at speeds of up to 190 kilometers per hour to impale blissfully ignorant prey with a lethal, iron-talon grip. Although rodents make up over three quarters of the diet of the Red-tailed or Red-shouldered hawk, they are opportunistic and will attack anything that moves including snakes, amphibians, crustaceans and even other birds. They are wholly carnivorous and require about four grams of meat a day for sustenance; one chubby chipmunk or half a squirrel. The hawk as mythological metaphor ranges from the hawk-headed Egyptian god Horus to the omniscient Native American sky-dweller. However, the most telling reference is from the ancient Greek poet Hesiod, who wrote Works and Days in about 700 BCE. In the “Fable of the Hawk and Nightingale” the author establishes the nature of injustice: “…said the hawk to the nightingale with speckled neck, while he carried her high up among the clouds, gripped fast in his talons, and she, pierced by his crooked talons, cried pitifully. To her he spoke disdainfully: ‘Miserable thing, why do you cry out? One far stronger than you now holds you fast, and you must go wherever I take you, songstress though you are. And, if I please, I will make my meal of you, or let you go. He is a fool who tries to withstand the stronger, for he does not get the mastery and suffers pain besides his shame.” Aesop, following a similar and probably derivative theme, applies the moral that a bird in the hand is worth two in the bush.