Reproductive biology of Synallaxis albilora (Aves: Furnariidae) in Pantanal of Poconé, Mato Grosso

Abstract

Synallaxis albilora (White-lored Spinetail) is a Neotropical ovenbird restricted to flooded areas in the Pantanal wetlands, central portion of South America. The aim of this work is to present a detailed description of its breeding biology (nests, eggs and nestlings) in the locality of Pirizal, Municipality of Nossa Senhora do Livramento, Pantanal of Poconé, at Mato Grosso State, Brazil. Several other aspects of its natural history are also described such as brood size, incubation period, parental care, nest further use by other species, agonistic interactions and nest-site. In order to study nest site, hemispherical photographs of vegetation above and north of each nest were taken. The photos were analyzed to estimate the canopy openness. The use of this method is considered unpublished in ornithological studies. Sixty nests were found and monitored during the years 2001, 2002, 2005 and 2006. The nest of S. albilora is similar to a retort, being built with pieces of kindling and lined with leaves. Its exterior consists of larger pieces of kindling and thorns. Both sexes were observed engaged in nest construction. The eggs are pyriform, whitish and present opaque surface (average of 20.5 x 16.4 mm, 2.8 g). Brood size was 3.35 ± 0.4 eggs (n = 20). The youngs are similar to the adults. A single individual was recorded engaged in incubation. Incubation time was 15.3 ± 0.7 days and the fledging time was of 13.6 ± 1.1 days. Canopy openness above nests was less than at five meters north of nests (16.4 and 20.3%, respectively; p = 0.036, n = 18). These data suggest that S. albilora might exhibit a preference for more open canopy cover sites. Several groups were observed using old nests. Agonistic interactions were registered during the reproductive station. The reproductive period of this species extends from August to December.