SPECIES

Red-tailed Hawk Buteo jamaicensis Scientific name definitions

C. R. Preston and R. D. Beane
Version: 1.0 — Published March 4, 2020
Text last updated May 20, 2009

Behavior

Locomotion

Walking, Hopping, Climbing, Etc

Walks on ground using slow, awkward steps; most often exhibited while feeding on carrion. Hops on ground in energetic, erratic fashion while chasing insect prey or confronting snakes (Bent 1937b).

Flight

Normal, flapping flight is generally slow (2.6 beats/s), ponderous, and direct (Blake 1948a). Ground speed estimated at up to 62 km/h (Broun and Goodwin 1943), and air speed up to about 90 km/h (Kerlinger 1989a). Maneuverable enough to successfully hunt in thick stands of conifer (Lowe 1978). Thermal and declivity currents are used for soaring, and weather conditions can influence soaring incidence (Preston 1981, Bildstein 1987a). More likely to soar in light winds; “kites” in strong winds, particularly on hillsides that face into the wind, likely using deflection updrafts for lift (Hoover and Morrison 2005). Soaring incidence and height increase during moderate winds (to about 32 km/h), but all flight is generally curtailed during very high winds. Soaring altitude during migration reported to 839 m (Kerlinger et al. 1985a). Suggested functions of soaring include migration, courtship, territorial advertisement, exploration, foraging, and thermoregulation. However, neither thermoregulation nor foraging was indicated as a function of soaring in a study in Arkansas (Ballam 1984). Red-tails spent twice as much time soaring as was predicted from foraging cost-benefit ratio, and birds sought shade, reduced activity, or panted to reduce heat stress (Ballam 1984).

Swimming and Wading

Little information. However, a Red-tailed Hawk reported foraging on waterfowl in shallow water (Jehl 2004b).

Self-Maintenance

Preening, head-scratching, stretching, bathing, anting, etc.

Preening session includes recurrent use of uropygial gland, often combined with feather erection; plumage usually shaken vigorously. Head scratching common, usually performed with anterior 2–3 talons of either foot applied to side of head. During stretching, wing and leg on same side of body are extended for several seconds while bird balances on opposite leg. May also lean slightly forward, balance on both legs, and extend both wings for several seconds before returning to typical perching posture. Occasionally bathes both in captivity and the wild.

Sleeping, roosting, and sunbathing

Commonly roosts in tree with dense foliage; groups of trees used more often than single tree (Preston 2000). Usually roosts singly or with 1–2 other Red-tails (relationships unknown) in same group of trees; occasionally shares large winter roost site with Ferruginous Hawks (Beane 1996). Individuals often use same roost site, and even roost tree, for several nights to several weeks (Preston 2000). Sleeps standing erect (sometimes balanced on one leg) with eyes closed.

Daily time budget

Active about 15 h/d in summer and about 11 h/d in winter; these figures roughly correspond to the number of daylight hours in each season. Diesel (Diesel 1983) reported that, in summer, adult Red-tails spend about 3% of active period soaring, 1% in flapping flight, and 96% perched. In winter, he found that both juveniles and adults spend about 93% of active period perched. Juveniles spent less than 1% of active period soaring and 6% flapping, whereas adults spend a little more than 1% of active period soaring and 5% flapping. Other sources indicate Red-tails may spend up to 25% of active period soaring (Ballam 1984, Janes 1984b).

Agonistic Behavior

Physical interactions

Generally aggressive. Intruders in breeding territory may be chased and attacked with wings and talons (feet open); these encounters sometimes include talon locking (grappling) between territory holder and interloper (Palmer 1988f). Intra- and interspecific aggression reduced and sporadic outside breeding season. Aggressive encounters during migration include vocalizations, talon locking, and aerial displays (Warren 1890b). In New Mexico, two dead females with talons locked together were recovered under a power transformer in January; they had apparently been electrocuted during an aggressive interaction (Dickerman 2003).

Communicative interactions

In an aggressive perching posture, body and head are held upright, and feathers of head, neck, and breast are erected (Figure 5). Upon escalation, hawk may fix eyes on intruder, and lean slightly forward. In submissive posture, head is held low, and feathers sleeked against body (Palmer 1988f). On ground, aggression is conveyed when feathers of head, neck, and breast are erected, wings extended, and beak held agape. Aggression is also signaled through various flight displays. These usually include exaggerated wingbeats and circling maneuvers, often accompanied by repeated screams (see Vocalizations).

In Sky-dance display (illustrated in Palmer 1988f), bird dives steeply from high altitude, checks descent and shoots immediately upward at similarly steep angle; this is repeated several times in succession.

Spacing

Territoriality

Highly territorial during breeding season. Territories 3-dimensional; conspecifics flying above defended airspace are usually unchallenged (Preston 2000). Boundaries often follow well-defined physical features (road, waterway, forest edge; Fitch et al. 1946b) and remain remarkably stable year-to-year, and even decades, regardless of turnover of individuals (Janes 1984a, Janes 2003b, Moorman et al. 1999). Size of defended area not well-documented, but mean of 33 territories in Oregon was 2.3 km2 (Janes 1984b). Mean size of 16 territories in Luquillo Experimental Forest in Puerto Rico was 124 ha, with smallest territories located in areas with high slope and easterly aspects (Boal et al. 2003). Nests may occur in clusters within a habitat, with regular spacing within a cluster. Minimum internest distance reported -- 0.32 km (Seidensticker and Reynolds 1971). Nesting densities may be related to perch distribution as well as food availability.

Territoriality relaxed in northern range during winter; several birds may gather in close proximity around local food source, especially carrion (Preston 2000). After northern-breeding individuals migrate and settle into southern over-wintering areas, however, they may become aggressive and actively defend territories (Brown and Amadon 1968). In Puerto Rico, territory defended year-round (Santana and Temple 1988).

Little information available regarding individual distance, but at least up to five birds observed perched in same tree during winter, the closest birds within 1 m of one another (Preston 2000). Members of a pair regularly perch next to one another on same branch (Petersen 1979a).

Sexual Behavior

Mating system and sex ratio

Typically monogamous, but 3 adults reported at 1 nest each in California (Wiley 1975b) and Wisconsin (Santana et al. 1986d).

Pair bond

Usually maintain pair bonds until death of a partner, at least in non-migratory (resident) populations, but acquisition of a new mate can occur rapidly after the death of 1 member of the pair (Bent 1937b, Petersen 1979a). No information on maintenance of pair bonds in migrants.

Courtship displays

Prenesting displays typically consist of both birds soaring in wide circles at high altitudes and the male performing maneuvers similar to the Sky-dance. After several series of dives and ascents, the male slowly approaches the female from above, extends his legs and touches or grasps her momentarily (Conner 1974a). Frequently, both birds dangle their legs during aerial maneuvers. The birds may grasp one another's beak or interlock talons and spiral toward the ground. Two birds thus engaged struck the ground before releasing one another; both flew away apparently unharmed (Voelker 1969). These aerial acrobatics may last 5–10 min and include courtship feeding. One member of a pair (presumably the male) attempted unsuccessfully to pass a snake to his mate as she rolled over (feet skyward) in mid-air to reach it (Hubbard 1974b). Piercing screams (as above) and quiet, raspy calls often accompany courtship flight displays (Fitch et al. 1946b).

Copulatory displays

Typically, copulation occurs when the female terminates courtship flight and postures from a perch. The female postures by tilting forward until her body is nearly horizontal and fluttering her wings loosely several times (Fitch et al. 1946b). The male spirals down to her and alights on her back, often steadying himself by flapping his wings or bracing them on nearby branches. Copulation usually lasts 5–12 s. Copulation may be followed by a period of soaring and aerial acrobatics or, less frequently, by quiet perching (Fitch et al. 1946b).

Extra-pair copulations

None reported.

Social and Interspecific Behavior

Degree of sociality

Typically occur singly or in pairs. May gather in small groups around abundant food source in winter or flock together during migration. These are assemblages gathered in relation to temporary environmental opportunities (easily obtained food or favorable soaring conditions) and involve little or no social interaction.

Play

Sometimes play with object in midair; repeatedly dropping and catching it (Lowe 1978).

Nonpredatory interspecific interactions

Often harass and are harassed by other buteos; Golden Eagle (Aquila chrysaetos) and Bald Eagle (Haliaeetus leucocephalus) in California regularly harassed, chased, and attacked, especially near Red-tail nest (Fitch et al. 1946b). In October in Pennsylvania, Red-tail attacked circling Bald Eagle from above before the two birds moved slowly away from one another (Robinson 2000).

Interspecific territoriality exists between Red-tail and Swainson's Hawks in Alberta (Rothfels and Lein 1983), Oregon (Janes 1984b), and Chihuahuan desert of Mexico (Thiollay 1981a). Aerial combat between territorial Red-tail and Swainson's hawks in Oregon may last nearly an entire day (Janes 1984b).

In Puerto Rico, Broad-winged Hawks (Buteo platypterus) defended nesting territories from Red-tailed Hawks, successfully driving away 84% (n = 25) of intruding Red-tails (Hengstenberg and Vilella 2005).

Aggression by Red-tails against Great Horned Owl (Bubo virginianus) in breeding season includes chasing and attacks with talons (Preston 2000). Attacks may be initiated and won by either species. Great Horned Owls often use nests built by Red-tails in a former year, and generally nest earlier.

Robs and is robbed by other buteos and Bald Eagle in winter. Single Red-tail in Colorado drove two adult Ferruginous Hawks from freshly killed prairie dog (Cynomys ludovicianus) in winter by repeatedly leaping at one of the hawks, talons thrust forward and wings extended; contact was made on at least 2 of 4 of these thrusts (CRP).

Typically dominates individual crows at a carcass (Prior and Weatherhead 1991), but during winter in Kansas, large flocks of crows successful in harassing Red-tails from carcass (Langley 2001). During winter in Virginia, Red-tail usurped a woodpecker killed by a Sharp-shinned Hawk (Accipiter striatus) (Wilson 1994a).

Mobbed by many bird species. In Oklahoma, Scissor-tailed Flycatcher (Tyrannus forficatus) attacked and rode a Red-tail down into roadside vegetation before both birds flew away (Hepworth 1966). Some small birds (commonly Passer domesticus) become tenants in active Red-tail nests (Petersen 1979a, Wilson and Grigsby 1979). In Sonoran Desert, Arizona, Red-tails followed hunting badgers (Taxidea taxus) and attempted to take prey escaping from them (Devers et al. 2004).

Predation

Great Horned Owl often cited as predator of nestling Red-tails, and may occasionally prey on adults; evidence is meager (Palmer 1988f). Corvids prey on eggs (Fitch et al. 1946b) and nestlings (Wiley 1975a).

Red-tailed Hawk Figure 5. Aggressive, perching posture; also used by birds in the hand.
Enlarge
Figure 5. Aggressive, perching posture; also used by birds in the hand.

By J. Schmitt.

Recommended Citation

Preston, C. R. and R. D. Beane (2020). Red-tailed Hawk (Buteo jamaicensis), version 1.0. In Birds of the World (A. F. Poole, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.rethaw.01