Variation in Breeding of the Shrike-like Tanager in Central Brazil

Abstract

The Shrike-like Tanager (Neothraupis fasciata) is a Cerrado bird considered as near threatened. Its life history is poorly known, especially its reproduction. We monitored reproduction during four breeding seasons (2003-2006) with 120 nests in a protected area in central Brazil. Nesting began at the end of the dry season and start of the rainy season. The incubation (13.0 days) and nestling (11.7 days) periods were shorter than for most neotropical birds, but similar to some other tanagers. Clutch size (2-3 eggs) was similar to most tropical birds. However, clutch size increased and nest initiation date advanced ,30 days in a year of early precipitation compared to 3 other years with regular or late precipitation. The Shrike-like Tanager had breeding flexibility and ability to adapt to changes in temporal precipitation patterns. Received 23 July 2010. Accepted 21 December 2010. Understanding population dynamics is of fun- damental importance in ecology, evolution, and conservation, especially in regions with habitat loss or other anthropogenic degradation. The Shrike-like Tanager (Neothraupis fasciata), the only species in this genus, occurs in the Cerrado (neotropical savanna) and is classified as near threatened (IUCN 2009). It is a generalist forager (Alves 1991) occurring at altitudes from 500 to 1,100 m (Ridgely and Tudor 1994). It constructs a basket-shaped nest ,1 m above ground (Alves and Cavalcanti 1990) and often is a sentinel in mixed species flocks (Alves 1990, Ragusa-Neto 2000). It is monogamous, forms flocks of up to six individuals and is a cooperative breeder (Alves 1990). Clutch size is usually two or three (Alves and Cavalcanti 1990). It is one of the few of the .800 cerrado birds whose breeding has been studied (Marini 1992; Lopes and Marini 2005a;