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

Movements and Migration

Migration Overview

Diurnal, partial, short- to intermediate distance migrant (most movements <1500 km); rarely makes water crossings of > 25 km. Although the species is not known to migrate trans-equatorially, small numbers of migrants in se. Costa Rica each autumn (P. Porras, pers. comm.), together with observations of three migrants at a migration watchsite in n. Colombia in autumn 1999 and 2000 and spring 2000 (Castaño R and Colorado Z 2002), suggest that small numbers migrate at least as far as s. Central America and n. South America in most years.

Migration is complex and varies annually depending on weather, especially the extent of prolonged snow cover. Overall, northernmost populations migrate earlier than more southerly populations, apparently in a leap-frog manner (Bent 1937b). Many birds breeding in northern regions migrate south, remaining absent from breeding grounds for 3–5 mo. Even in harsh winters with extensive snow cover, however, some northern birds over-winter near their breeding territories (e.g., Lowe 1978). Many birds breeding in mid-latitudes (45°–50°N) over-winter near breeding territories. Those that vacate the breeding range may remain absent for only a few weeks. Most breeders in the s. U.S. and n. Mexico are resident year-round and share over-wintering grounds with migrants from farther north. South of n. Mexico, most birds are resident year-round.

Timing and Routes of Migration

Spring migration begins as early as Feb, but northern breeders may arrive on breeding grounds as late as Jun (see Figure 6). Compared to immatures, adults over-winter closer to breeding range and arrive on breeding grounds earlier (Haugh 1972b, Brinker and Erdman 1985). Generally, juveniles begin autumn migration earlier than older birds (Haugh 1972b, Geller and Temple 1983), but, reportedly, this pattern is reversed in Alaska (Kessel and Springer 1966). For arrival times at breeding sites, see also Breeding: phenology.

During autumn in e. North America, migrating individuals concentrate along topographic features known as leading lines where their numbers are monitored at more than 125 traditional migration watchsites in Canada, the US, Mexico, and Costa Rica (Kerlinger 1989a, Zalles and Bildstein 2000). Migration in w. North America proceeds along a broader, more diffuse front, with few locations reporting high densities in autumn or spring, and with considerable yearly and seasonal variation in the number of individuals counted (Hoffman et al. 1992b).

Eastern Red-tails from northern latitudes begin moving south in Aug; migration usually ends by early Dec. Red-tail counts during autumn migration at Hawk Mountain, in e. Pennsylvania, have averaged 3,329/yr since 1934 and 3,679/yr in 1990 through 2005 (Hawk Mountain). Bednarz et al. (Bednarz et al. 1990b) reported a decline in Red-tail numbers at Hawk Mountain from 1971 through 1986.

A more recent analysis (1976 – 2004) indicates decreasing trends of 1.9% (P < 0.01) per year at Hawk Mountain and 1.8% (P > 0.10) at Cape May Bird Observatory in s. New Jersey. Ninety percent of all Red-tails pass Hawk Mountain and Cape May between 9 Oct and 1 Dec and 9 Oct and 27 Nov, respectively, with peak migration typically occurring during the 1st week of November at both sites (C. Farmer, D. Hussell, and D. Mizrahi, pers. comm.). Red-tails made up 18% and 4% of the overall flights at Hawk Mountain and Cape May, respectively, in 1976-2004, the difference between the two reflecting, in part, the tendency of this species to migrate along inland rather than coastal corridors.

Autumn migration in ne. Wisconsin exhibits a bimodal pattern, with initial northbound movements of dispersing juveniles mid-Aug through mid-Sep, followed by a major southbound movement in early Oct through mid-Nov, initially of immatures, with adults predominating in Nov (Brinker and Erdman 1985). Farther west, autumn counts at Goshute Mountains, NV (1983-2001), Lipan Point, AZ (1991-2001), Wellsville Mountains, UT (1977-1979, 1987-2001), and Manzano Mountains, NM (1985-2001), averaged 2,962/yr, 1,760/yr, 502/yr, and 616/yr, respectively, with all four sites reporting consistent increases through the mid-1990s, but mixed trends since then through 2001 (Hoffman and Smith 2003).

Autumn migration generally ends several weeks earlier in w. North America than in e. North America, with approximately 95% of movements at interior sites in the West occurring between 23 Aug and 2 Nov (Hoffman et al. 1992b).

The direct path between breeding and wintering areas of Red-tails trapped along the Kittatinny Ridge in e. PA determined from banding data was 215° (Holt and Frock 1980), a direction that coincides with mean track directions and headings of visible migrants in central NY State (Kerlinger et al. (Kerlinger et al. 1985a) -- indicating that Red-tails typically fly directly toward migratory goals.

Regional details pertaining to timing and routes (largely from banding recoveries) have been reported for a few areas across the U.S. Sixteen Red-tails recovered in Arkansas (wintering) were banded outside the state, mostly on breeding grounds, but some during migration. The paths between banding and recovery showed a longitudinal dichotomy in the distribution of Red-tails that over-winter in Arkansas. Birds recovered in e. Arkansas originated from nesting areas east and north of the mid-western states, whereas those recovered in w. Arkansas originated in prairies to the north and west of Arkansas (James and Neal 1986). Although none of the recovered birds were identified to subspecies, the pattern suggests that migratory Red-tails over-wintering in e. Arkansas are primarily borealis and those recovered in w. Arkansas primarily “kriderii” and calurus.

Red-tailed Hawks banded as young in sw. Idaho travel long distances (>1500 km) with a strong directional bias (Steenhof et al. 1984). Nine of 12 distant returns were southeast of the breeding grounds; 6 in coastal lowlands of Mexico and Guatemala. Recoveries of autumn migrants banded or color-marked along the Kittatinny Ridge in e. Pennsylvania indicate that ridge-flying migrants there overwinter in s. Pennsylvania and Maryland, south to the Carolinas and the Florida panhandle, and west to central Kentucky, and breed at least as far north as s. Quebec (Holt and Frock 1980, B. Silfies, pers. comm.).

Thirty Red-tailed Hawks captured during autumn or spring migration in New Mexico, Nevada, Oregon, and Washington (1999-2000), that were outfitted with satellite transmitters and tracked for up to 2.5 yr, followed the expected boundaries of the Rocky Mountain, Intermountain, and Pacific Coast flyways (sensu Hoffman and Smith 2003), respectively; with most demonstrating both high inter-season and among-year migration path fidelity, and with one individual traveling as far south as s. Guanajuato, (central) Mexico (J. Smith pers. comm.).

Migratory Behavior

Timing and rate of migration are influenced by weather, particularly snow cover, and food supply. Cold fronts stimulate movements at Hawk Mountain Sanctuary, with increased rates of passage on the first two days following frontal passage (Allen et al. 1996). Contrarily, high prey availability may delay migratory movements (Craighead et al. 1969). Overall, there is considerable local movement of over-wintering birds in response to weather fluctuations and prey availability (Preston 2000). An abnormal mid-Sep peak in migration in Tadoussac, s. Quebec, in 2005 consisting almost entirely of adult individuals, was attributed to a catastrophic breeding failure in e. Quebec (B. Droulet, pers. comm.). During migration along ridges in mid latitudes, Red-tails exhibit gliding flight more frequently (> 79%) than any other form of flight. Individuals are more likely to engage in thermal soaring and gliding early in autumn, and slope soaring and gliding later in the season, due to seasonal shifts in availability of these respective types of updrafts (Maransky et al. 1997).

Kerlinger (Kerlinger 1989a) reported mean air speed as 60 km/h and mean ground speed as 47 km/h for ridge-gliding Red-tails. Average altitude of 196 migrating Red-tails radar-tracked in one study was 839 m (Kerlinger et al. 1985a). Red-tails generally migrate alone, or in small, loosely organized flocks and tend to avoid crossing large bodies of water, thus concentrating along shorelines, peninsulas, and similar topographic features.

Control and Physiology of Migration

Among autumn migrants trapped along Lake Michigan in central Wisconsin, juveniles caught later in the season were fatter, better muscled, and smaller overall than those caught earlier, presumably because the latter were from more northerly populations, with less time to prepare for their migrations, or because they had traveled father before being trapped (Geller and Temple 1983).

Weather, see above; physiological data needed.

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Red-tailed Hawk

Buteo jamaicensis

Abundance

Estimates of relative abundance for every week of the year animated to show movement patterns. Relative abundance is the estimated average count of individuals detected by an eBirder during a 1 hour, 1 kilometer traveling checklist at the optimal time of day for each species.   Learn more about this data

Relative abundance
0.05
0.12
0.56
Week of the year

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