Tony Silva NEWS: The races of Amazona aestiva. PART II

Tony Silva NEWS

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Read also the first part of this article:

Tony Silva NEWS: The races of Amazona aestiva. PART I

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My attempts to clarify the taxonomic status of Amazona aestiva has taken me into the archives of museums in Brazil, the US and Europe and has resulted in the examination of specimens in the field and housed as pets in situ across all parts of the range. I have also contacted and received the valuable opinion of Antonio Chacón in Argentina, who for over 45years has traded in wild and captive bredindividuals, and the extremely knowledgeable Brazilian aviculturist Renato Costa, who specializes in Amazona aestiva. My current view as expounded here is not etched in stone and is likely to change in the future, but represents data gathered over a period of 30 years.

a) From the early 1600s to the 1700s, Brazil´s chief exports were sugar, which left from the port of Salvador in Bahia, and sugar and mining from Rio de Janeiro; Salvador was Brazil´s capital until 1763, when it moved to Rio de Janeiro, whose significance by then had grown.On the shipping boats carrying sugar and the products of mining, other items left the country, including live birds. In the Archives of Indies in Seville, Spain there are shipping manifests containing the lists of the personal items of mariners visiting the tropics and some of these lists mention live parrots as personal articles. It is thus safe to assume that the parrot used by Linné was brought to Europe by a mariner, who sold it for a pet; the bird was then either painted with its owner (as was common at the time) and thus used to describe the species or seen alive or as a skin by Linné, who documented its appearance.Whatever the source, it is not available for examination, but it is likely the bird originated from the southern part of the range or more likely the contact zone (as the bird identified in Linné´s description suggests and as assigned by Hellmayr), which would have been close to the exporting port of Rio de Janeiro.

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The yellow on the head can be extensive. (c) Frank. This file is licensed under the Creative Commons Attribution 2.0 Generic license.

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b) The Auáis in my opinion the most striking, separable form. It is more proportionate in shape and invariably has pale blue on the forehead followed by golden yellow, which forms a bib; its color scheme is like that found in the Cuban Amazon Amazona leucocephala, with the white being blue and the red in the throat being replaced by yellow. In the core range the birds are carbon copies of one another. Males typically have reddish bases to the throat feathers. The range centers on a line that extends from Goiás to Bahia, Tocantins and Piauí, possibly extending to southernmost Maranhão, where I have seen multiple caged birds.

Does this distinctness allude to the Auá being a separate species or is a separable subspecies?

Based on current taxonomic principals, forAuá to be regarded as a valid and distinct species from aestiva, it would have to come in contact with aestiva and not hybridize. As an example, Amazona ochrocephala and Amazona farinosa come in contact within parts of their range but they are clearly separate species because they do not hybridize. Subspecies, however, are allowed to cross when they come in contact with each other.

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A comparison of aestiva and xanthopteryx. (c) Tony Silva

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For years I thought that Auá did not hybridize with the typical aestivabut I have seen individuals in the wild at the periphery of the range where they come in contact with aestiva that did not have the defined yellow bib; indeed the birds clearly displayed features that suggested a cross between Auá and aestiva. Data from molecular genetics studies suggests that the true Auá are genetically different. This form also seems to nest terrestrially in termitaria, though much more research needs to be conducted. This concept of ground nesting may seem ludicrous, but the same skepticism surfaced when in Psittaculture (1991) I indicated that Alipiopsitta xanthops bred in terrestrial termitaria and was not an Amazon parrot; it was at the time known as Amazona xanthops. Now it is widely accepted that xanthops commonly nests terrestrially and that it is a member of a separate genus (Alipiopsitta).

My hypothesis is that theAuá is a distinctive form that will eventually be classified as a subspecies. That it hybridizes with aestiva is as pointed out acceptable at a subspecies level.

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Auá male depicting the typical red throat. (c) Tony Silva

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c) The contact zone between aestivaand xanthopteryx is very broad. Throughout much of central and southern MatoGrosso and Paraná, Brazil, the two forms integrate freely; some populations also appear to hybridize with Amazona ochrocephala and this will eventually result in a restructuring of the species we currently regard as distinct or allied. Birds from these zones, even from the same clutch, can display predominately red or an equal distribution of red and yellow from the bend of the wing. The intergradation is acceptable at a subspecies level and thus does not impugn the validity of a subspecies.

d) Within Brazil, one finds tremendous variability in the amount of yellow and blue on the head, but there is constancy if one examines a large enough series of birds. In general terms, birds from Brazil north of southern MatoGrosso, MatoGrosso do Sul and São Paulo have limited amounts of yellow on the head; it rarely extends beyond the ear coverts and typically extends just past the rear part of the periophthalmic ring. The blue is restricted to the forehead and forecrown. South of these three states, one finds birds with much more color. I have found individuals at Bonito in MatoGrosso do Sul, Poconé in MatoGrosso and Itapetininga in São Paulo that had yellow extend beyond the ear coverts to the latter part of the crown and throat. These individuals occurred in populations of less colorful individuals.

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The Blue-fronted Amazon on the left. Sometimes the yellow color is not visible at all. (c) Snowmanradio. This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.

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Brazilian specimens from the north-east are larger and longer than those from MatoGrosso and São Paulo but smaller than xanthopteryx from the Chaco.

Individuals from Bolivia, Paraguay and Argentina also show tremendous color and size variation. Birds from eastern Paraguay and most of Formosa province in adjacent Argentina tend to be smaller and duller compared to those from the Chaco region, which are more colorful (sporting more yellow on the head and the bend of the wings), are larger, possess a longer tail, have hints of yellow to the thighs and have lighter green underparts, often bluish hinted. Individuals slightly smaller than those from the Chaco and possessing less yellow to the head, more blue on the head, more red to the bend of the wing and a darker green underside occur in western and north-western Salta and Jujuy in Argentina, central Paraguay and central Bolivia. Individuals with an equal amount of yellow and blue to the head, the blue being lighter, and about the same amount of red and yellow to the wing occur in Santiago del Estero and Tucumán in Argentina. In size they resemble Chacoan birds.

The Chacoan form appears to nest at a different time than the other types. As an example, within the Argentina range, which extends from Juan José Castelli in Chaco Province to the city of Joaquín V. Gonzalez in Salta and south to Santiago del Estero, the young fledge up to a month after the other types.

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e) Individuals with significant blue in the face (the yellow being restricted to the periophthalmic region) occur in all populations, but in Brazil appear to be concentrated to the southern states of São Paulo, Rio de Janeiro, Paraná and Rio Grande do Sul. Some of these populations are likely introduced. These birds possess both red and yellow in the wings.

The Brazilian blue-headed birds differ significantly from the individuals found in the Sierra de Santa Bárbara in the Argentine states of Salta and Jujuy. These individuals display an opaque green color, completely green bend of the wing and green heads with sometimes a blue wash but no yellow. They are small in size and are slim in build. In many ways they resemble an Amazonamercenaria. This population seems isolated and thus would appear to be genetically distinct. Attempts to study it have not been carried out. Aviculturally speaking this form may be novel but its dull coloration would not make it coveted.

f) The bird currently called Pyrrhura perlata perlata was once called Pyrrhura rhodogaster, until evidence surfaced that in fact the skins used to name the red bellied form were in fact perlata, the Pearly Conure, another species. I believe that the same has occurred with Amazona aestiva: the form named by Linné was in fact the form subsequently identified by Berlepsch as xanthopteryx, leaving the red wing form without a name and making Berlepsch´s xanthopteryx This leaves open this species to name changes.

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READ THE THIRD PART OF THIS ARTICLE ON THE NEXT WEDNESDAY!

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Title photo: (c) Pablin79. This file is licensed under the Creative Commons Attribution-Share Alike 2.0 Generic license.

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