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SWAINSON’S HAWK Buteo swainsoni 48–56cm, WS 119–132cm. Fairly large
but lightly built migrant buteo with relatively long tapered wings, notably
variable plumage; often best identified by structure. Winters mainly in
agricultural land, especially sugar cane fields, also marshes, savannas; ranges
widely in migration. Best known as a spring and fall transient, when 1000s
stream overhead, often with Turkey Vultures and Broad-winged Hawks.
Wintering birds mainly seen soaring in mid–late morning, often with kettles of
vultures, or hunting with other hawks over burning cane fields. Flight buoyant
and agile, soaring with wings in a shallow V. Perches readily on ground, also on
low bushes, trees, utility poles. In flight note relatively narrow, tapered wings with contrast between pale
coverts and dark flight feathers; light-morph adult has dark breast band. At rest note long wings, projecting
to or just beyond tail tip, small head and bill. Uncommon dark morph has dark body contrasting with
pale undertail coverts, rusty underwing coverts. Juv. has buff face and underparts, fading to whitish, with
dark eyestripe and mustache. Cf. larger and bulkier White-tailed and Red-tailed Hawks. Mostly silent.
STATUS: Common transient on both slopes and through highlands, late Sep–Nov, late Feb–early May.
Rare to uncommon and irregular in winter, mainly on Pacific slope, occasionally inland to Central Valley.
(Breeds N America to Mexico, winters Mexico to S America.)
RED-TAILED HAWK Buteo jamaicensis 48–59cm, WS 117–137cm. Large,
rather stocky hawk, mainly in highlands. Varied semi-open habitats with trees
or utility poles for perches, forest edge; not in forested humid lowlands. Soars
with wings slightly raised to flattish, glides on flattish wings; hunts from perches
and in flight. Kites and hovers, mainly in open country when windy. Note
thickset shape with broad, rather blunt-tipped wings, medium-length tail (1st-
year has narrower wings, longer tail); light morph has dark leading edge to
underwing. Plumage highly variable (dark morph rare in Costa Rica); migrant
adult (rare) has whitish underwings, variable dark belly band. On perched
birds, all except darkest morphs show distinct pale mottling on scapulars. Adult has diagnostic rusty tail.
Juv. can be confusing, note size and structure, brown tail with numerous narrow dark bars, cf. Swainson’s
Hawk (narrower, longer wings), Short-tailed Hawk (smaller, rarely seen perched). Attains adult appearance
in 2nd year. SOUNDS: Classic Hollywood hawk scream: drawn-out, rasping, overall descending whieeéahrr,
mainly in flight; juv. has higher, shriller wheéirr, at times repeated persistently. STATUS: Uncommon to
fairly common on both slopes, mainly 1500m to timberline, locally down to 800m. More widespread
Oct–Mar, when small numbers of n. migrants (mainly imms.) occur locally in nw. lowlands, rarely
elsewhere on both slopes. (N America to Panama.)
WHITE-TAILED HAWK Geranoaetus albicaudatus 48–59cm, WS 124–
137cm. Large hawk, local in open country, especially drier areas with scattered
trees and bushes; also marshes and ranchland. Perches mainly on low posts and
bushes. Soars and glides with wings in distinct shallow V; at times kites and
hovers, especially over fields being burned; hunts mainly in flight. Note long,
broad-based, and tapered wings, short tail (1st-year has distinctly narrower
wings, longer tail); at rest, wing-tips project past tail, especially on adult. Adult
distinctive, with bold tail pattern, but cf. light-morph Short-tailed Hawk; 1st-
year variable, most are extensively dark below, a few mostly whitish below with
limited dark streaking, cf. Red-tailed Hawk; 2nd-year resembles adult but darker above, with dark hood,
duller tail pattern, variable narrow dark barring on belly. Attains adult appearance in 3rd year.
SOUNDS: Mostly quiet away from nest. Short, slightly hoarse screams, often couplets in short series, whee-
ah whee-ah.…STATUS: Uncommon to scarce and local in nw. lowlands, to 1500m, rare (at least formerly)
inland to Central Valley and in interior valleys of s. Pacific slope; declining with increased agricultural
development. (Mexico and sw. US to S America.)
