Appearance

Penelopina is a monotypic genus. Highland Guan is pheasant-sized and sexually dimorphic. Females are on average larger than males. The adult male is glossy black with red legs, bill, and wattle. The female is brown barred black, with gray bill and dull reddish legs. The male’s display call and wing rattling are unmistakable. Warning calls are distinctive.

The altitudinal range of Highland Guan extends from 700 to 3300 m, where Crested Guan (Penelope purpurascens) is sympatric in the area below 2000 m, Plain Chachalaca (Ortalis vetula) is sympatric on the Atlantic slope up to 2000 m, and White-bellied Chachalaca (Ortalis leucogastra) on the Pacific slope up to 900 m. West Mexican Chachalaca (Ortalis poliocephala) is sympatric in the westernmost part of Highland Guan’s range. The range of Highland Guan overlaps also with Horned Guan (Oreophasis derbianus) in areas above 2000 m, and with Great Curassow (Crax rubra) below 1600 m. Highland Guan is rather shy and often only seen running away, therefore it can be confused with all of the above mentioned cracids, with Crested Guan and Plain Chachalaca being the most similar species. Howell and Webb (1995) pointed out that based on a poor illustration of Crested Guan in Peterson and Chalif (1973), this species was frequently misidentified as Highland Guan in Mexico. The ground-dwelling sympatric Thicket Tinamou (Crypturellus cinnamomeus), Slaty-breasted Tinamou (C. boucardi), and Buffy-crowned Wood-Partridge (Dendrortyx leucophrys) have red legs similar to Highland Guan, but are shorter tailed. Under good observation conditions, however, Highland Guan is unmistakable: the male is the only all black cracid in its range, further distinguished by its bright red tarsi, and the uniformly barred plumage of the female also is unique among sympatric cracids. Flushing birds usually utter a distinctive warning call.

Adult male: Based on specimens from throughout the Highland Guan’s range, Vaurie (1968) described the plumage of the adult male as “pure black, with a dark blue or greenish gloss which varies individually and is highly developed on the upper parts with the exception of the rump, the lower abdomen being sooty, rather than pure black, and not glossy”.

Adult female: Based on specimens from throughout the guan’s range, Vaurie (1968) described the plumage of the adult female as “the ground color of the feathers of the upper parts varies from pale brown to dark fuscous brown on the head, and from buffy brown to ochraceous cinnamon, or pale russet on the back and wings, the ground color of the tail being more rufous than the color of the back. The feathers of the head are dark brown at the center, the dark center contrasting with the pale edges; the feathers of the back and tail are very heavily vermiculated, or barred with dark fuscous brown, the pale bars being narrower than the dark interspaces, except on the tail where the dark and pale bars are of about the same width. The bars of the tail are not invariably regular, as the dark bars are in some cases more or less wavy and regular. The under parts are paler than the upper parts and are chiefly grayish buffy brown, less rufous than the back, and are less heavily vermiculated and barred, the dark bars being paler and more irregular, especially on the upper breast which in some is more mottled than barred”.

Immature male: Vaurie (1968) described the plumage of the immature male as “blacker than that of the adult female, but is not uniformly black as in the adult male. The head is dull black, but not perfectly uniform, as the feathers are more or less edged with reddish brown. The feathers of the back and tail are chiefly black, but are interrupted by bars or heavy vermiculation which varies from dull pale chestnut to rufous cinnamon, the pale bars being more regular and broader on the upper tail coverts, and the tail being vermiculated rather than barred. The under parts are grayish buffy brown, but darker than in the adult female, and more or less regularly barred with very dark buff.”

Immature female: The plumage of the immature female “resembles that of the adult female but is much less regularly and distinctly patterned” (Vaurie 1968).

Juveniles: Chicks were described for the first time by Andrle (1967), summarized by Delacour and Amadon (1973) as follows: “A broad, black band down top of the head and hindneck, bordered by buffy stripes. The black line becomes more extensive on the back, but paler, mixed with brown. Wing coverts, quills and tail quills somewhat browner, darkest on breast, palest on throat.”

There is no detailed information available on molt of Highland Guan. Juvenile cracids are precocial. Remiges develop already inside the egg, which enables chicks to short flights few days after hatching (Wagner 1953). Because juvenile remiges are soon too small to carry the adult weight, they are molted for the first time in the first weeks of life, described on Plain Chachalaca (Ortalis vetula; Stresemann and Stresemann 1966, Marion 1977, Pyle 2008). Young resemble adults when still much smaller than adults (del Hoyo 1994). Young male Highland Guans resemble females, and acquire the black plumage in the second year (Wagner 1953, Vaurie 1967, del Hoyo 1994).

Male

Iris: reddish brown (Blake 1977; K. Eisermann, personal observations)

Eye ring: “brownish red”, “reddish brown” (Vaurie 1968); dull reddish brown (Andrle 1967)

Bill: bright red-orange or coral red (Vaurie 1968)

Wattle: bright red-orange or coral red (Vaurie 1968)

Tarsi and toes: bright red-orange or coral red (Vaurie 1968)

Female

Iris: reddish brown (Blake 1977; K. Eisermann, personal observations)

Eye ring: dusky (van Rossem 1934)

Bill: brown (Vaurie 1968)

Tarsi and toes: brownish red (Vaurie 1968)

Juveniles (about 1 week old)

Iris: dark, bluish gray (Andrle 1967)

Bill: black, with white tip and pale pinkish-white cere (Andrle 1967)

Tarsi and toes: purplish vinaceous (Andrle 1967)

Highland Guan is sexually dimorphic with females on average larger than males. Total length ranges 590-650 mm (Blake 1977). The following table gives data of the largest series of published measurements (Blake 1977). Previous smaller series of measurements (van Rossem 1934, Ridgway and Friedmann 1946) did not show the differences and are not included here. Mass was reported 866-914 g (del Hoyo 1994, Dunning 2008).