Um caso de albinismo em tachã (Chauna Torquata, Oken) (Aves, Anseniformes) ocorrido na estação ecológica do Taím, Rio Grande do Sul, Brasil

Abstract

It is described herein a case study of albinism in Chauna torquata Oken, 1816 (Southern screamer) occurred at the Ecological Station of Taim, Rio Grande do Sul. Brazil. Screamers are birds of marshes, wet grasslands and forest lagoons. The bill is short and curved, the head is small and slender and the neek rather short. The strong wings are armed with two large, sharp spurs on their forward edge. The feet and legs are fleshy, the lower half of the tibia is bare, and the three long front toes show just a trace of webbing between them, They are often seen walking in pairs on the floating masses of vegetation or in large groups for feeding. The albino specimen described herein was observed feeding in the midst of a group of almost fifty birds. Their plumage was white but their legs and bill were normally red pigmented, and also presented a light grey ring on its neek. It did not represent a case of total albinism, in which pigment should be totally absent.