The breeding of some species of Dendrocolaptidae and Furnariidae in the central Monte desert, Argentina

Abstract

Different aspects about the breeding of seven bird species belonging to the families Dendrocolaptidae and Furnariidae that nest in the Reserve of Ñacuñán (Mendoza Province), central Monte Desert, are presented. The laying period of Drymornis bridgesii and five species of Furnariidae spanned from early October to mid January. The duration of this period was 1–2.5 months. Cranioleuca pyrrhophia, Asthenes baeri and Synallaxis albescens built their closed nests in 5–8 days. Leptasthenura platensis usually nested in abandoned nests of other ovenbirds (A. baeri and C. pyrrhophia) and Rhinocrypta lanceolata. C. pyrrhophia, A. baeri, S. albescens and L. platensis selected chañar (Geoffroea decorticans) trees larger than those available in the habitat for nesting. Mean clutch size was 3 eggs in D. bridgesii and L. platensis, 2.9 and 2.7 eggs in C. pyrrhophia and S. albescens, respectively, and 5 eggs in A. baeri. The size and weight of L. platensis eggs tended to be smaller than in other Argentinean breeding areas. The incubation period lasted between 14 and 15.5 days in those species in which this parameter could be measured (D. bridgesii, C. pyrrhophia, A. baeri and L. platensis). The chicks of D. bridgesii remained 21 days in the nest and those of C. pyrrhophia left the nest in 13–15 days. The observed predation patterns in the closed nests of several ovenbirds’ species suggest that Milvago chimango may be an important predator of these nests in Ñacuñán.