Taxonomy, distribution, and conservation of \'caboclinhos\' of the complex Sporophila bouvreuil (Aves: Eberizidae)

Author(s)

Érika Machado Costa Lima

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2008-08-06

Examining board members

Luis Fábio Silveira; Herculano Marcos Ferraz de Alvarenga; Mônica de Toledo Piza Ragazzo

• Advisor: Luis Fábio Silveira

Abstract

Four subspecies of Capped Seedeater (Sporophila bouvreuil) are currently accepted: S. b. bouvreuil, S. b. pileata, S. b. saturata and S. b. crypta. While male-specific plumage patterns differ among subspecies, female plumages are similar, what makes it difficult to identify female specimens to subspecific level. The present project had as goals a evaluation of the validity of the latter subspecies, using morphological characters, and their distributions. We analyzed 174 specimens of Sporophila bouvreuil, comprising 109 specimens of S. b. bouvreuil, 30 specimens of S. b. pileata, six specimens of S. b. saturata and 29 specimens of S. b. crypta. We used bill length, height and width, as well as wing, tail and tarsi length. Our analysis of plumage color patterns was based on characters that included all body regions. Morphometric data did not suggest significant differences among Sporophila bouvreuil subspecies, and only S.b. bouvreuil and S. b. pileata were diagnosable using plumage patterns. Based on those results, we propose that S. b. pileata should be considered a full species, namely Sporophila pileata (Sclater, 1864). Since S. b. bouvreuil, S. b. saturata and S. b. crypta were not diagnosable based on morphometric or plumage coloration, we propose that those taxa should be synomized to Sporophila bouvreuil (Müller, 1776). We identified two areas of sympatry between S. bouvreuil e S. pileata, in localities at western state of Minas Gerais, as well as western and southeastern state of São Paulo. It was not possible to reconstruct the migration routes of S. bouvreuil and S. pileata based solely on museum specimens, in absence of field data. However, our data suggest that there are movements of Amazonian populations of S. bouvreuil towards drier regions during wintering, where part of Cerrado and Caatinga populations breed. Atlantic forest populations are sedentary, and stay in their territories during breeding and wintering periods. Concerning S. pileata, we conclude that Cerrado and Mata Atlântica populations breed in their respective biomes, but available data did not allow further conclusions about their wintering areas. (AU)