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Black-mandibled Toucan

Ramphastos ambiguus

Black-mandibled Toucan

  • Order: Piciformes
  • Family: Ramphastidae
  • Polytypic 2 Subspecies

Authors: Rice, Ari A., J. D. Weckstein, and J. Engel

Identification

Summary

The Black-mandibled Toucan is a large species distinguished from others by its size, yellow face and throat, and bicolored black and yellow bill.

Similar Species

For the most part, Black-mandibled Toucans do not overlap with any similar species. The Choco Toucan (Ramphastos brevis), which occurs west of the Andes, looks very much like a Black-Mandibled Toucan, but the two species do not overlap in geographic distribution.

The Chestnut-mandibled Toucan (Ramphastos swainsonii), which occurs farther east than the Choco Toucan, is not known to overlap extensively with Black-mandibled, but it is worth mentioning because of its extreme similarity and potential conspecificity. Black- and Chestnut-mandibled toucans are virtually identical in terms of habits and plumage, and if they were to occur in the same area, would perhaps be best told by bill color (a much lighter maroon-brown color in R. swainsonii). Thus, range remains the distinguishing factor. According to Haffer (1974), nominate Black-mandibled Toucan (R. a. ambiguus) lives exclusively in montane forests on the eastern Andean slope. Another subspecies, abbreviatus, which is found in the central Andean valleys of Colombia, is thought to meet the Chestnut-mandibled Toucan in the central Magdalena valley. Here, the two species are indistinguishable and may hybridize, although further research on the contact between these two taxa is needed in this area (Haffer 1974, Stiles et al. 1999).

Vocalizations

Vocalizations are very similar, if not identical to Chestnut-mandibled Toucan Ramphastos swainsonii (Ridgely and Greenfield 2001, Schulenberg et. al 2007). Main call is a series of loud, far-carrying yelps. The tempo and number of notes vary, but most calls start with a loud introductory note followed by several shorter (often doubled) notes decreasing slightly in pitch. Locals often describe this call as “Díos te dé te dé” (“God give you” in Spanish) (e.g. Haffer 1974, Short and Horne 2001). It is uttered from the tops of tall trees, sometimes in duet, and can be heard year-round (Schulenberg et al. 2007).

Nonvocal Sounds

Wing-rustling is produced by two notched outer primaries, a trait common to all Ramphastos toucans.

Detailed Description (appearance)

Adult male:

Body black except for face, throat, upper breast, and tail coverts. Hindneck and upper back black with maroon-reddish tint. Feathers turn browner with wear (Short and Horne 2001). Face, throat, upper breast, and auricular areas bright yellow. Yellow extends to middle breast and is bordered by lines of white and crimson. Uppertail coverts white; crissum deep to bright red. Bill is long, and curved along the culmen, especially near the tip; for bill colors, see Bare Parts.

Adult female:

Similar to male in all respects except for a shorter, “blockier” bill (Short and Horne 2001).

Immature:

No information.

Bare Parts

Adult:
Bill is very long (see Measurements). Maxilla largely yellow, a greenish yellow stripe running down the culmen, and a thin black basal line that borders the base. Mandible black.
Orbital skin may be sky-blue (ambiguus) or yellow-green (abbreviatus) (Haffer 1974, Hilty and Brown 1986, Restall et al. 2006). Iris color is also quite variable, ranging from gray, to brown, to dark green, to olive-yellow (Short and Horne 2001). Tarsi and toes are blue or blue-gray.

Immature:
Based on what we know from the closely related Chestnut-mandibled Toucan (Ramphastos swainsonii), bill is probably shorter, duller, and less distinctively marked.

Measurements

The following measurements are from Short and Horne (2001). The format of these measurements is as follows: range (mean).

R. a. ambiguus:

Wing Length

220-248 (229.2) mm (male; n=27); 206-248 (219.5) mm (female; n=22)

Tail Length

155-173 (162.4) mm (male; n=24); 148-165 (158.1) mm (female; n=20)

Bill Length

153-198 (167.26) mm (male; n=27); 131-151 (143.31) mm (female; n=23)

Tarsus

51-59 (54.7) mm (male; n=24); 47-55 (51.43) mm (female; n=22)

Mass

620-740 g (male; n=3); 599 g (female; n=1)

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R. a. abbreviatus:

Wing Length

217-243 (224.4) mm (male; n=8); 207-234 (217.5) mm (female; n=17)

Tail Length

No information

Bill Length

152-175 (164.5) mm (male; n=8); 129-148 (141.24) mm (female; n=17)

Tarsus

No information

Mass

No information

Molts

No information.

Geographic Variation

There are two recognized subspecies of Black-mandibled Toucan, which are not believed to overlap in geographic distribution. As Short and Horne (2001: 249) note, “Differences between subspecies are very small, involving bill color features that are not absolute, nor is the color of orbital skin likely to be of much importance." However, the nominate race (R. a. ambiguus) occurs on eastern Andean slopes, averages slightly larger than R. a. abbreviatus, and has blue (as opposed to yellow-green) facial skin.

Systematics

The Black-mandibled Toucan is one of 7 to 15 species level taxa in the genus Ramphastos (de Germiny 1929, Peters 1948, Meyer de Schauensee 1966, 1970, Haffer 1974, Short and Horne 2001, 2002). Among the Ramphastos toucans, there are two sister clades, as suggested by Haffer (1974) and later supported by DNA evidence (Weckstein 2005, Patané et al. 2009). One subgenus-level clade, known as “smooth-billed yelpers” includes R. ambiguus, Chestnut-mandibled Toucan (R. swainsonii), and White-throated Toucan (R. tucanus). The other clade, known as “channel-keel-billed croakers” includes Keel-billed Toucan (R. sulfuratus), Choco Toucan (R. brevis),  and several other species that make croaking vocalizations. Patane et al. (2009) analyzed mitochondrial DNA sequences among the Ramphastos taxa and found that Black-mandibled Toucan is sister to R. swainsonii and together these two are sister to R. tucanus.

There has been ongoing debate as to whether Chestnut-mandibled and Black-mandibled toucans should be considered conspecific. The geographic ranges of the two species do not seem to overlap except in the central Magdalena valley in Colombia, where R. swainsonii may or may not still occur (Hilty and Brown 1986, Stiles et al. 1999).

The taxznomic status of R. a. abbreviatus (the subspecies occurring in the Magdalena valley) adds further complexity to the situation. It possesses a black lower mandible, but unlike R. a. ambiguus, has green orbital skin (more like Chestnut-mandibled Toucan). Although abbreviatus currently is considered to be a subspecies of Black-mandibled Toucan, others regard it as a “stable hybrid” or even a subspecies of Chestnut-mandibled based on range and transitional appearance (Stiles et al. 1999,  Short and Horne 2001).

For years, Chestnut- and Black-mandibled toucans were considered separate species based on the assumption that the Choco Toucan (R. brevis) was actually a subspecies of Black-mandibled (and thus sympatric with Chestnut-mandibled) (Peters 1948). However, others have shown that R. brevis and R. ambiguus are not closely related, based on vocal characteristics (Todd 1947, Haffer 1974) as well as DNA sequences (Weckstein 2005, Patané et al. 2009). As Short and Horne (2001) describe it: “Only with the realization that the Choco Toucan is, in fact, a distinct species was it possible to recognize the allopatry of ambiguus and swainsonii, and their very close relationship.” According to Weckstein (2005), Chestnut- and Black-mandibled toucans are 1.35% different in mitochondrial DNA, but again, more studies are needed to determine species status.

Recommended Citation

Rice, Ari A., J. D. Weckstein, and J. Engel. 2010. Black-mandibled Toucan (Ramphastos ambiguus), Neotropical Birds Online (T. S. Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology; retrieved from Neotropical Birds Online: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=27206