The Rufous Motmot is the second largest species of motmot. The appearance of both subspecies, the nominate Baryphthengus martii martii and B. martii semirufus, is similar and dominated by two features, a prominent black mask and a long, narrow graduated tail. The tail of semirufus is tipped with the racquets so characteristic of the family, but racquets are absent in martii of the northwestern Amazon basin. Both sexes are similar in appearance having a cinnamon-rufous head and breast contrasting with intense green/blue-green on the mantle, wings and upper surface of the tail. Females are slightly smaller than males.
The Broad-billed Motmot (Electron platyrhynchum) is nearly identical to Rufous Motmot in general appearance but is smaller (42-49 vs. 31-39 cm long; Snow 2001) and appears somewhat paler overall. The major distinguishing plumage characteristic of Broad-billed Motmot is the green throat and chin patch, although this feature is not present in Electron platyrhnchum platyryhnchum, which occurs west of the Andes in Colombia and Ecuador (Snow 2001); and the Broad-billed Motmot has a green, not rufous, belly. The call of the Broad-billed Motmot is a hoarse cawcawcaw or more rapidly repeated cacacacaca, reminiscent of many trogon calls but dissimilar to those of the Rufous Motmot. The Rufous-capped Motmot (Baryphthengus ruficapillus) of the Atlantic Forest region of eastern South America is considerably smaller, and is primarily green on the head and breast with the rufous coloration confined to the crown and a band across the belly (Snow 2001). The call is described as a burst of deep resonant bubbling notes, bubububububub (Belton 1984).
The following description is compiled from Sharpe (1892), Forshaw and Cooper (1987), Stiles et al. (1989) and Snow (2001):
Adult: Sexes similar. The head, neck and breast are a deep cinnamon-rufous, somewhat lighter on the throat and upper breast and darker on the crown and lower breast. The rufous coloration is interrupted by two elongate black spots present on the chest, each consisting of two larger feathers and several smaller ones sometimes appearing as a single larger spot, and a characteristic large black mask extending from the base of the bill to the ear coverts and curving downward behind the eye. The mantle is greenish olive while scapulars and wings are a deep forest green suffused with rufous and tinged greenish blue on the rump, lower belly, and on the inner margins of the primaries. The outer margins of the primaries are deep violet-blue. The long, graduated, narrow tail is forest green at its base shading to a deep rich greenish-blue towards the tips of the rectrices. The racquets are basically blue shading to black at the tips. The underside of the tail is grayish-black. The two central rectrices are up to 110 mm longer than the adjacent ones with a relatively short length of bare shaft leading to the racquets. The nominate Baryphthengus martii martii possesses elongated central rectrices that gradually broaden at the tips but lacks racquets entirely. This subspecies also comes in pale and dark variants but otherwise both subspecies are basically identical in appearance with some variation in size (see Measurements).
Immature: Not described.
No data available.
The following descriptions are based on Snow (2001):
Iris: Deep orange-red to brown in darker variant of Baryphthengus martii martii.
Bill: The decurved, slightly hooked, black bill is broad at the base but relatively narrow otherwise. It is coarsely serrated along the middle portion of both the upper and lower mandible.
Tarsi and toes: Dark gray in both subspecies and sexes.
The following measurements are derived from Wetmore (1968), Forshaw and Cooper (1987) and Snow (2001):
Total length: Male Baryphthengus martii martii 42 - 47 cm.
Wing: Male martii (n = 36 specimens), 140-160 mm (mean 149.5 mm); semirufus (n = 42 specimens), 144-163 mm (mean 154.0 mm); female martii (n = 26 specimens), 137-159 mm (mean 148.1 mm); semirufus (30 specimens), 145-159 mm (mean 152.0 mm).
Tail: Male martii (n = 36 specimens), 200-298 mm (mean 244.4 mm), semirufus (n = 42 specimens), 211-336 mm (mean 269.2 mm); female martii (n = 26 specimens), 210-260 mm (mean 236.0 mm), semirufus (n = 30 specimens), 232-304 mm (mean 266.8 mm).
Mass: Male martii 146-160 g, semirufus 185-193 g; female martii 153-173 g, semirufus 170-208 g.