Abstract

We studied the breeding biology of the Wren-like Rushbird (Phleocryptes melanops) during three reproductive seasons from 2005 to 2008 in the Santa Elena lagoon, province of Nuble, south-central Chile. Reproductive activity was initiated with courtships during the late winter and finished with nest abandonment during the early summer. The first eggs hatched during the early spring after egg-laying plus incubation period of 15-23 days. The chicks left the nest sites at almost three weeks old when they had juvenile plumage. Nests were shaped as covered vessels with a small lateral entrance and all were built in stands of Pale Rush (Juncus procerus) with material obtained from the same rushes. We present quantitative data on nest dimensions and nest locations. Eggs were oval (length = 19.6 ± 1.8 mm (mean ± DS), width =15.5 ± 1.8) and the outer surface of the eggshell was bluish. Chicks were feed by both parents in an alternate manner. Prey delivered to nestling and fledlings were nymphs and naiads of Odonata (48.6% of all item prey), spiders (20%), naiads of Diptera (11.4%), Oligochaeta (11.4%), Acrididae (5.7%), and Neuroptera (2.3%). Based on 42 nests and 104 eggs, we estimated a average clutch size of 2.5 ± 0.6 eggs (range = 1-3). Almost 60% of eggs successfully hatched. The final reproductive success (= [ratio fledglings/ all laid eggs]) was relatively low (46.1%). Known causes of nesting failures included hatching failure, starvation flooding, and destruction and predation by rodents. Wren-like Rushbirds were tolerant to the presence and nesting of the Many-colored Rush-Tyrant (Tachuris rubrigastra), another rush-specialist passerine. Most of our results were consistent with previous observations made elsewhere. Knowledge on breeding biology of wetland-specialist birds is fundamental to better address problems associated with human-made landscapes and habitat restoration of freshwater systems. © The Neotropical Ornithological Society.