New record of aberrant plumage in Blue-black Grassquit (Volatinia jacarina Linnaeus, 1766, aves: Emberizidae)

NOTES AND COMMENTS

New record of aberrant plumage in Blue-black Grassquit (Volatinia jacarina Linnaeus, 1766, aves: Emberizidae)

Gaiotti, MG.^*; Pinho, JB.; Grangeiro, D.

Programa de Pós-graduação em Ecologia e Conservação da Biodiversidade, Universidade Federal de Mato Grosso – UFMT, Av. Fernando Corrêa da Costa, 2367, Boa Esperança, CEP 78060-900, Cuiabá, MT, Brazil

The Blue-black Grassquit Volatinia jacarina (Linnaeus, 1766), popularly known in Brazil as "tiziu", is an inhabitant of open areas, and also common near cities (Marcondes-Machado, 1988). The most remarkable characteristic of this species is the male blackish blue iridescent plumage, especially during the reproductive season (Queiroz, 2008). Nevertheless, variation in this colouration pattern is not uncommon, being noted mainly in captive specimens, with few observations in wild individuals (Piacentini, 2001). Herein, we report a new record of aberrant plumage colouration of the wild Volatinia jacarina from Mato Grosso state, Brazil. Nine individuals of V. jacarina were mist netted between 17-22 November 2009 during an environmental impact study in "El Dourado" farm (52° 14' 12" W and 15° 32' 01" S), municipality of Barra do Garças. Of these, one individual presented a different plumage colouration that consisted of very clear almost yellow across the head and many dorsal clear spots (Figure 1).

Following the plumage colour classification proposed by Nemésio (1999) we describe this individual as "arlequins" colouration. This class is the most common variation form and consists in total suppression of melanin in the bird's head (Nemésio, 1999; Piacentini, 2001). The variation of plumage colouration can be explained by some factors such as exogenous (e.g. food) or endogenous (e.g. relative mating) (Nemésio, 2001). Some studies relating structural plumage characters to indicators of quality and birds in poor condition may not be able to devote as much energy to the keratin deposition (Doucet, 2002). These changes are more common in captive specimens, due to food and partner limitation by the caretaker (Nemésio, 2001). However, in wild birds these modifications are rare and only found in few species, such as Vanellus chilensis (Franz and Fleck, 2009). Although extensively studied and widely distributed (Dias and Macedo, 2009), to the best of our knowledge this is the first record of aberrant colouration in Volatinia jacarina.

Acknowledgements – We thank Robson W. Ávila for critical suggestions and PASCON for logistical support.

Received December 14 ,2010

Accepted January 21, 2011

Distributed May 31, 2011

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Publication Dates

• Publication in this collection
  15 July 2011
• Date of issue
  May 2011