Emerald toucanet

Emerald toucanet
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Emerald toucanet (nominate group)
Conservation status
Least Concern (IUCN 3.1)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Piciformes
Family:	Ramphastidae
Genus:	Aulacorhynchus
Species:	A. prasinus
Binomial name
Aulacorhynchus prasinus (Gould, 1834)

The emerald toucanet (Aulacorhynchus prasinus) is a near-passerine bird occurring in mountainous regions from Mexico, through Central America to northern Venezuela and along the Andes as far south as central Bolivia. Some taxa currently included in this species are sometimes split into separate species (see Taxonomy).

Description

Like other toucans, the emerald toucanet is brightly marked and has a large bill. The adult is 30–35 cm (12–14 in) long and weight can range from 118–230 g (4.2–8.1 oz). The sexes are alike in appearance, although the female generally is smaller and slightly shorter-billed. It is, as other members of the genus Aulacorhynchus, mainly green. The vent and tail-tip are rufous. The bill is black with yellow to the upper mandible (amount depends on the exact subspecies) and, in all except the nominate (prasinus) and wagleri groups (see Taxonomy), a white band at the base of the bill. The members of the caeruleogularis group have a rufous patch near the base of the upper mandible, while some members of the albivitta group have a rufous patch near the base of the lower mandible. The throat is white in the nominate and the wagleri group, blue in the caeruleogularis and cognatus group, pale grey-blue in the lautus group, blue or black in the atrogularis group, and white or grey-blue in the albivitta group. The eye-ring ranges from blue to red, in some subspecies very dark, almost appearing blackish from a distance. The legs are dull greyish and the iris is dark.

Juveniles are duller, including the throat, and, depending on subspecies, the black areas of the bill are replaced with dusky or the bill is entirely yellowish.

Habitat and behavior

File:Aulacorhynchus prasinus -Costa Rica-8.jpg

Despite their bright colours, emerald toucanets, such as this individual in Costa Rica, can be surprisingly difficult to see

The emerald toucanet is a generally common in humid forest and woodland, mainly at higher elevations. The 3–4 white eggs are laid in an unlined hole in a tree, usually an old woodpecker nest, but sometimes a natural cavity. Both sexes incubate the eggs for 14–15 days, and the chicks remain in the nest after hatching. They are blind and naked at birth, and have short bills and specialised pads on their heels to protect them from the rough floor of the nest. They are fed by both parents and fledge after about 6 weeks. They are fed for several weeks after leaving the nest.

Small flocks, usually consisting of 5–10 birds, move through the forest in "follow-my-leader" style with a direct and rapid flight. This species is primarily an arboreal fruit-eater, but will also take insects, lizards, small birds, and their eggs.

The calls of the emerald toucanet are a loud dry rrip rrip rrip rrip rrip and a graval graval graval. It has been suggested that the two different calls are given by the two sexes. There are also croaking alarm and aggression calls.

Taxonomy

File:Aulacorhynchus prasinus - NBII Image Gallery-2003.jpg

This subspecies, cyanolaemus, is the only member of atrogularis group with a blue (not black) throat. No other subspecies has less yellow to the bill

File:Aulacorhynchus prasinus -Belize Zoo -upper body-8a.jpg

At Belize Zoo (nominate group)

File:Emerald Toucanet JCB.jpg

In Santa Elena, Costa Rica

It has been suggested that the emerald toucanet actually should be split into 7 species (below described as they roughly occur from north to south):

• Wagler's toucanet (Aulacorhynchus wagleri). Endemic to south-western Mexico. Monotypic.
• Emerald toucanet (Aulacorhynchus prasinus). Found from southern Mexico to Nicaragua. Includes subspecies warneri, virescens, stenorhabdus, chiapensis and volcanius.
• Blue-throated toucanet (Aulacorhynchus caeruleogularis). Found in Costa Rica to western Panama. Incl. subspecies maxillaris.
• Violet-throated or Nelson's toucanet (Aulacorhynchus cognatus). Found in eastern Panama and adjacent far north-western Colombia. Monotypic.
• Santa Marta toucanet (Aulacorhynchus lautus). Endemic to the Santa Marta Mountains in northern Colombia. Monotypic.
• (North) Andean toucanet (Aulacorhynchus albivitta). Found in the Andes from western Venezuela, through Colombia to northern Ecuador. Incl. subspecies griseigularis and phaeolaemus.
• Black-throated or Peruvian toucanet (Aulacorhynchus atrogularis). Found from southern Ecuador, through Peru, far western Brazil (in the state of Acre), to central Bolivia. Incl. subspecies dimidiatus and cyanolaemus.

These splits are mainly based on morphology and plumage as described by Navarro et al. (2001). Their results were preliminary, as they themselves pointed out. As a result most authorities, notably SACC, do not recognize more than a single widespread species, but recognize the need for a solution to this complex. They are clearly separate species as per the phylogenetic species concept, but judging the species limits as per the biological species concept is difficult due to the entirely allopatric distributions of the various groups. There are no major vocal differences between the various populations, but that in itself is not unusual for separate species that do not overlap.

Genetic evidence has to some extent supported the above splits, although with different borders between the species in the northern Andes, and of the above suggested species, data is lacking for lautus. According to their genetic results, the north Ecuadorian toucanets, which are white-throated and usually included in albivitta, are closer to the atrogularis group than the "true" albivitta of Colombia and Venezuela. Assuming this is correct, it seems likely that north Ecuadorian toucanets represent a new taxon, which should be treated as a subspecies of A. atrogularis. They also found that griseigularis was closer to the atrogularis group than albivitta, but unlike the north Ecuadorian toucanets, they opted for treating it as a separate species, the grey-throated or plumbeous-throated toucanet (A. griseigularis). In that case, A. albivitta is known as the white-throated toucanet. If albivitta and griseigularis are treated as separate species, it is unclear where phaeolaemus belongs, as genetic data for that taxon is missing. In appearance and distribution phaeolaemus is closest to griseigularis, but, inexplicably, it has been suggested it should be treated as a subspecies of A. albivitta. In 2011 it was also suggested that cyanolaemus should be treated as a subspecies of A. albivitta, but this was presumably an error, as it directly contradicts genetic data, which place it in A. atrogularis.

Another potential problem relates to the distribution limit between A. cognatus and A. caeruleogularis in Panama. Although the reason for this treatment is unclear, the population in central Panama has been placed in A. caeruleogularis, which would limit A. cognatus to extreme eastern Panama and adjacent Colombia. According to George Angehr, author of The Birds of Panama, it is possible toucanets from central Panama actually are closer to A. cognatus.

Aviculture

In captivity eating a grape
(nominate group)

The emerald toucanet is a popular pet toucan. It is affectionate when hand-fed and loves to play and interact with its owner. Emerald toucanets are as quick to learn tricks as cockatoos. They are active and need a large cage for their size, including perches that they can hop back and forth on. They also require a high-fruit diet, without which they are susceptible to a disease of excessive iron storage that is similar to hemochromatosis in humans.

External links

• Bibliography of online, ornithological articles which explore the natural history of the Emerald toucanet, Aulacorhynchus prasinus prasinus
• Stamps (for Belize, El Salvador, Honduras, Mexico and Nicaragua) at bird-stamps.org
• Emerald toucanet videos, photos, and sounds at the Internet Bird Collection
• Emerald toucanet photo gallery at VIREO (Drexel University)
• Emerald toucanet species account at NeotropicalBirds (Cornell University)

• Interactive range map of Aulacorhynchus prasinus at IUCN Red List maps