Appearance

Slaty-tailed Trogon is a relatively large trogon. The male has green upperparts and breast, slate-black wings with vermiculated black and white wing panel, red underparts, and slate-colored undertail, with a stout orange bill and an orange red orbital ring. The female has dark gray upperparts, wings, and upper breast, red underparts, and dark gray upper and undertail; the bill is dark gray above, with a dull orange mandible.

Male Slaty-tailed Trogon may be confused with male Black-tailed Trogon (Trogon melanurus) in southern regions of Panama and northwestern Colombia; male Black-tailed Trogon has dark blue uppertail and deep golden-yellow (not reddish or orange) bill, and has a narrow white band separating the green breast from the red belly. Females of these two species also are very similar, but the mandible of female Black-tailed is yellow, not reddish as in female Slaty-tailed. There also is overlap in western Colombia and Ecuador between Slaty-tailed Trogon and Blue-tailed Trogon (Trogon comptus), another species with a completely dark undersurface to the tail. Blue-tailed Trogon has a pale iris, however, and a yellow bill. There is no known overlap between Slaty-tailed Trogon and Ecuadorian Trogon (Trogon mesurus), although the distributions of these two species approach one another in northwestern Ecuador. Both sexes of Ecuadorian Trogon have a white iris, and male Ecuadorian has a narrow white band between the green breast and red belly. Other red bellied trogons that overlap with Slaty-tailed Trogon are smaller, and have white on the undersurface of the tail. The barring on the underside of the tail of Lattice-tailed Trogon (Trogon clathratus) is not very prominent, however; Lattice-tailed Trogon can be distinguished, however, by its pale iris and yellow bill.

The following description is based primarily on Ridgway (1911) and Wetmore (1968); see also Howell and Webb (1995) and Geographic Variation:

Adult male: Chin, upper throat and sides of head dull black. Upperparts generally metallic green; more bluish green on the crown, rump, and uppertail coverts, and more golden green on the back. Upper surface of the four central rectrices metallic green to bronze green, tipped with black; the adjacent rectrices black, but with metallic green outer webs; outermost rectrices entirely black. Undersurface of the rectrices slate gray, rectrices tipped with black. Wing coverts (except anterior portion of lesser wing coverts) and secondaries delicately vermiculated with black and white (giving a pale gray appearance); alula, primary coverts, and primaries dull black or slate-black, outermost primaries edged with pale gray or grayish-white proximally. Breast shining metallic green to bronze green. Belly, underparts, and undertail coverts deep red. Tibial feathers sooty blackish.

Adult female: Similar to male, but green of upperparts and breast replaced by gray. Head, neck, back, scapulars, rump, uppertail coverts, chest, plain slate or dark gray, darker on chin, throat, and sides of head; paler on lower breast. Rest of underparts deep red or geranium-red; tibial feathers blackish. Wings blackish slate or sooty slate; coverts and secondaries minutely and indistinctly freckled with paler markings; outer primaries edged with white basally. Uppersurface of tail blackish or slate-black, sometimes slightly darker that rest of upperparts; under tail slate, glossed with violaceous, middle rectrices more slaty and tipped with black.

Immature male: Similar to adult male throughout but with outer rectrices tipped white and narrowly barred with white on distal portion of outer vanes and usually on distal portion of inner vanes; middle rectrices duller iridescent bronze-green than adult and without black tip. Wing panel more coarsely vermiculated, secondaries spotted or mottled with dull white or buffy white along edges; underparts similar to adult female but with some green on chest.

Immature female: Similar to adult female, but outer rectrices and secondaries marked with white as in juvenile male; undertail also as juvenile male. Outer rectrices of both sexes of immature narrower and more pointed than in adults.

Nestling: Tawny-brown to black throughout; upperparts dull brown, wings dull black, except for buffy secondaries and coverts; breast plain wood brown, underparts speckled with buff on patchy white.

Little information. Tashian (1952) mentioned a specimen collected in August showing molt on the head and rectrices. Foster (1975) also noted the beginnings of molt on a specimen from August; this specimen had somewhat enlarged testes, suggestive of overlap of molting and breeding.

Iris: hazel, dark brown, light brown, pale golden brown (male) or orange brown (female)

Orbital ring: dull red, salmon, orange, or pinkish orange (male), duller in female

Bill: deep orange red (male); or maxilla dusky gray with dull orange at base along tomia and mandible dull orange (female). Bill of immature male similar to that of female.

Tarsi and toes: dull yellowish brown or gray (male) or light brown (female)

Bare parts information from (Ridgway 1911), Tashian (1952), Storer (1961), and Wetmore (1968).

Total length: 30-33 cm (Hilty and Brown 1986), 32-33 cm (Ridgely and Greenfield 2001b), 33-35.5 cm (Howell and Webb 1995)

Linear measurements (from Ridgway 1911):

male (n = 28)

wing length: mean 173.2 mm (range 163-181 mm)

tail length: mean 170.8 mm (range 161-186 mm)

bill length (culmen): mean 24.5 mm (range 23-27 mm)

tarsus length: mean 16.4 mm (range 15.5-18 mm)

female (n = 24)

wing length: mean 174.1 mm (range 165-185.5 mm)

tail length: mean 171.9 mm (range 160.5-186 mm)

bill length (culmen): mean 24.2 mm (range 23-25.5 mm)

tarsus length: mean 16.2 mm (range 15-17.5 mm)

Mass: mean 141.0 g (n = 26, sexes combined) (Hartman 1961); male, mean 149.3 g (range 142.0-160.7 g, n = 5; Smithe and Paynter 1963); female, mean 148.5 g (range 141.3-155.6 g, n = 2; Smithe and Paynter 1963); mean 145 ± 12 g (n = 10) (Howe 1981).