Northern Emerald-Toucanet Aulacorhynchus prasinus

  • Order: Piciformes
  • Family: Ramphastidae
  • Polytypic: 7 subspecies
  • Authors: Thomas S. Schulenberg, A. M. Contreras-González, Claudia I. Rodríguez-Flores, Carlos A. Soberanes-González, Marîa del Coro Arizmendi, and Kolten Powell


Distinguishing Characteristics

Aulacorhynchus toucanets are small to medium-sized, green toucans. Northern Emerald-Toucanet is a small Aulacorhynchus, with a total length of 30-37 cm. The body primarily is emerald green, with chestnut undertail coverts and tips to the rectrices. The color of the throat varies geographically, and may be whitish or blue. The bill is long and laterally compressed, and is mostly black, but the maxilla is yellow (although the extent of yellow is another feature that varies geographically).

Similar Species

Within its range, Northern Emerald-Toucanet is the only species of Aulacorhynchus; no other green toucan occurs in this region, and so confusion with other species is extremely unlikely. There is unlikely to be any contact between the southernmost population of Northern Emerald-Toucanet, along the Panama/Colombia border, and the nearest population of Southern Emerald-Toucanet (Aulacorhynchus albivitta) of the Andes of Colombia. In any event, the throat of this population of Southern Emerald-Toucanet (subspecies griseigularis) is pale gray, not deep blue as in the southernmost population of Northern Emerald-Toucanet (subspecies cognatus).

Detailed Description

The following description is based on Short and Horne (2001), and refers to nominate prasinus of southeastern Mexico; see also Geographic Variation:

Adult: Sexes similar. Mainly green, tinged bronzy on the crown and forecrown, and with a yellowy bronze tint on the upper back. Underparts paler than the upperparts. The rectrices are deep blue distally, with broad chestnut tips (chestnut tips narrower, or occasionally lacking, on the central pair). Chin, throat, and malar white, grading into the green on the breast. Flanks bright yellow-green to green-yellow. Undertail coverts chestnut.

Immature: Similar to adult, but feathers duller (grayer, less yellow). Rectrices more pointed, with reduced chestnut tips, and the chestnut is browner and duller.


There is little information on molts in Northern Emerald-Toucanet (or in Ramphastidae in general), but it apparently follows the Complex Basic Strategy, with a partial Preformative Molt but no Prealternate Molt. Juvenile rectrices are narrower than in adults, and juvenile remiges and rectrices are retained in the Preformative Molt (Dickey and van Rossem 1938). The Basic Molt is initiated in El Salvador in adults in May, but may extend into November (Dickey and van Rossem 1938).

Bare Parts

Orbital skin: brownish slate, bluish slate, or black

Iris: gray-brown, dark brown, reddish brown, or chestnut

Bill: Shape typical of toucans: long, with a curved culmen, and serrated along tomia. Generally the maxilla is extensively yellow and the mandible is black, but there is considerable variation in pattern across subspecies; see Geographic Variation. In nominate prasinus, the maxilla is mostly yellow, and the mandible is mostly black. The base of the bill, in a narrow vertical stripe that extends downward from the nares, is yellow, orange, or white. There is a black patch at the base of the culmen, and a variable amount of black just above the "teeth" of the tomia. Occasionally there is a pale tip to the mandible.

Tarsi and toes: olive green, dull green, slaty green, or slaty blue; soles dusky yellow or ochraceous

Bare parts color data from Dickey and Van Rossem (1938), Wetmore (168), and Short and Horne (2001).


Total length: 29 cm (Stiles and Skutch 1989), 32-37 cm (Howell and Webb 1995), 34.5 cm (Jones 2004)

Linear measurements:

Mensural data (mm) for Aulacorhynchus prasinus (Short and Horne 2001). Males are larger in all dimensions, but the difference in bill length is particularly pronounced
subspecies sex wing tail bill tarsus
prasinus male mean (n) 126.0 (29) 116.7 (26) 79.3 (33) 33.5 (31)
range 121-132 109-125 73.0-92.1 31.2-36.1
female mean (n) 123.8 (22) 111.0 (21) 64.2 (25) 32.9 (25)
range 117-132 109-125 56.6-75.0 30.2-36.0
virescens male mean (n) 124.9 (21) 75.2 (21)
range 116-131 66.0-81.0
female mean (n) 121.8 (17) 61.2 (16)
range 118-128 54.0-68.2
volcanius male mean (n) 123.0 (9) 78.2 (9)
range 115-127 73.8-84.5
female mean (n) 116.5 (6) 63.6 (6)
range 108-127 61.2-66.7
wagleri male mean (n) 128.7 (33)
range 123-139
female mean (n) 126.3 (21)
range 117-135
caeruleogularis male mean (n) 122.8 (29)
range 117-130
female mean (n) 119.1 (22)
range 113-125
cognatus male mean (n) 121.3 (10)
range 117-127
female mean (n) ----- (4)
range 112-124

Other important sources of morphometric data for Aulacorhynchus prasinus include Wetmore (1968), Haffer (1974), and Winker (2000, 2016).

Mass: Data (g) from Short and Horne (2001):

prasinus, male: mean 189.7 g (range 163-239 g, n = 13)

female: mean 181.1 g (range 160-201 g, n = 7)

virescens, male: 187.2, 200 (g n = 2)

female: range 150-188 g(n = 3)

wagleri, male: mean 183.7 g (range 158-202, n = 16)

female: mean 179.1 g (range 159-189, n = 6)

caeruleigularis, male: mean 142.0 g (range 118-173, n = 5)

female: range 139-167 g (n = 3)

cognatus, male: range 160-184 g (n = 3)

female: 155 g (n = 1)

Recommended Citation

Schulenberg, T. S., A. M. Contreras-González, C. I. Rodríguez-Flores, C. A. Soberanes-González, M. d. C. Arizmendi, and K. Powell (2017). Northern Emerald-Toucanet (Aulacorhynchus prasinus), version 2.0. In Neotropical Birds Online (T. S. Schulenberg, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA.