Buffon's Macaw

The great green macaw (''Ara ambiguus''), also known as Buffon's macaw or the great military macaw, is a Central and South American parrot found in Nicaragua, Honduras, Costa Rica, Panama, Colombia and Ecuador. Two allopatric subspecies are recognized; the nominate subspecies, ''Ara ambiguus'' ssp. ''ambiguus'', occurs from Honduras to Colombia, while ''Ara ambiguus'' ssp. ''guayaquilensis'' appears to be endemic to remnants of dry forests on the southern Pacific coast of Ecuador. The nominate subspecies lives in the canopy of wet tropical forests and in Costa Rica is usually associated with the ''almendro'' tree, ''Dipteryx oleifera''.

Taxonomy

The great green macaw belongs to the genus ''Ara'', which includes other large parrots, such as the scarlet macaw, the military macaw, and the blue-and-yellow macaw.

This bird was first described and illustrated in 1801 by the French naturalist François Le Vaillant for his ''Histoire Naturelle Des Perroquets'' under the name "le grand Ara militaire", using a skin deposited at the Muséum national d'histoire naturelle in Paris. Le Vaillant states that it is not certain if the bird is truly a distinct species of parrot, or, as he thinks more likely, it is specific varietal race of the military macaw, but nonetheless, he must mention that its existence merits notice. The bird was subsequently named ''Psittacus ambiguus'' by the Thuringian Johann Matthäus Bechstein in the first tome of the fourth volume, published in 1811, of the series ''Johann Latham's Allgemeine Uebersicht der Vögel'', the greatly expanded German translation of the Englishman John Latham's ''A General Synopsis of Birds''. Bechstein mentions le Vaillant's reluctance to consider it as an independent species, but explains that having examined a living bird, he considers it a valid species, mentioning the size difference and enumerating numerous other characteristics he deems distinctive.

After almost 200 years, the binomial name was changed from ''Ara ambigua'' to ''Ara ambiguus'' in 2004, as it was decided that the word ''ara'' was in fact male, despite ending in an -a (see epicene).

There are two subspecies which are geographically isolated at present: ''Ara ambiguus'' ssp. ''ambiguus'', which has the largest distribution range (Central and northern South America), and ''Ara ambiguus'' ssp. ''guayaquilensis'', which only occurs in Ecuador. The Ecuadorian subspecies is sometimes referred to as Chapman's macaw or Chapman's green macaw. American naturalist Frank M. Chapman shot the type specimen of his proposed new taxon in 1922 on a hill in the Cordillera de Chongon, twenty miles northwest of Guayaquil, Ecuador, and first described the taxon in 1925 in a report on the newly collected bird skins he had brought back to the US from Ecuador.

Due to the morphological variability of ssp. ''guayaquilensis'', with a number of specimens of this taxon being identifiable as the military macaw, in 1996 Berg and Horstman, themselves referencing Fjeldså ''et al''., mentioned it might best be synonymised with ''A. militaris'', or suggested there might be gene-flow between all three populations. A 2015 study comparing the mitochondrial DNA of different populations of the military macaw and this species found that while these two species are clearly differentiated, as well as different populations of the military macaw in Mexico, no genetic difference between ssp. ''guayaquilensis'' and the nominate taxon was found (at least regarding the mitochondria). This indicates that the division of this species into two subspecies is likely not taxonomically valid. It is also possible that the Ecuadorian populations do not all belong to ssp. ''guayaquilensis''.

Description

Great green macaws are the largest parrots in their natural range, the second heaviest macaw species (although they are relatively shorter tailed than other large macaws such as the red-and-green macaw and are thus somewhat shorter), and the third heaviest parrot species in the world. This species averages in length and in weight.''CRC Handbook of Avian Body Masses, 2nd Edition'' by John B. Dunning Jr. (Editor). CRC Press (2008), . They are mainly green and have a reddish forehead and pale blue lower back, rump and upper tail feathers. The tail is brownish-red tipped with very pale blue. The bare facial skin is patterned with lines of small dark feathers, which are reddish in older and female parrots. Juveniles have grey-coloured eyes instead of black, are duller in colour and have shorter tails which are tipped in yellow.

The main morphological distinction with the subspecies ''guayaquilensis'' is that this bird has a smaller, narrower bill.

The great green macaw appears superficially similar to, and may easily be confused with, the military macaw where their ranges overlap.

Distribution and habitat

The great green macaw lives in tropical forests in the Atlantic wet lowlands of Central America from Honduras to Panama and Colombia, and in South America in the Pacific coastal lowlands in Panama, Colombia and western Ecuador, where they also occur in deciduous (seasonal), dry tropical forests. In Colombia, where both species occur, it prefers more humid woodlands than the closely related military macaw. The habitat where it breeds in Costa Rica is practically non-seasonal, evergreen rainforest, with rain some ten months of the year, a precipitation of 1,500 to 3,500 mm a year, and an average temperature of 27 °C throughout the year. In Costa Rica the habitats where great green macaws occur during breeding season is dominated by the ''almendro'' (''Dipteryx oleifera'') and ''Pentaclethra macroloba'', with secondarily raffia palms (''Raphia'' spp.) dominated wetlands. It is usually observed below 600 m above sea level in Costa Rica during the breeding season, but disperses to higher elevations to 1000 m after breeding, and can be seen as high as 1500 m in southern Panama.

The population in Ecuador is thought to be split into two disjunct areas in the western coast of the country, the coastal mountain range of the Cordillera de Chongon in southwestern Ecuador, and in the far north bordering Colombia from the west in Río Verde Canton in central coastal Esmeraldas Province, stretching eastwards into Imbabura Province. This bird is very uncommon in Ecuador. In Colombia it is reasonably common in the Darién region and the Gulf of Urabá near the Panamanian border, and is also found in the north of the Serranía de Baudó mountains on the Pacific coast, the West Andes, and found eastwards to the dry forests of the upper Sinú valley near the Caribbean coast. In Panama it is common in some areas such as the Caribbean slope and in parts of Darién National Park such as the famous Cana birdwatching site and across the Alto de Nique mountain and the adjacent border with Colombia. It is also found in Panama in the mountains of the Serranía de Majé near Panama City and the southern Cerro Hoya mountains. In Costa Rica in the early 2000s, the reproductive range of the great green macaw was thought to be restricted to 600 to 1120 km² of very wet forests in the northeast along the border with Nicaragua. After the breeding season this population disperse in larger groups to higher altitudes both southwards in the central cordillera of Costa Rica as well as northwards to Nicaragua. Another population was known by 2007 in the hills inland between Old Harbour and Sixaola near the northern Panamanian border. In Nicaragua there are populations in the east of the country in the Bosawás, Indio Maíz Biological Reserve and San Juan reserves. It occurs in a number of areas in eastern Honduras such as the Río Plátano Biosphere Reserve, where it is rare.

Historically this macaw had a larger range. For example: in 1924 it was collected in Limón, Costa Rica, in 1904 and 1907 around Matagalpa, Nicaragua

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