Breeding Success and Social Mating System of the Bay-capped Wren-Spinetail (Spartonoica maluroides)

LLAMBIAS, PAULO E. ; FERRETTI, VALENTINA ; CARDONI, DANIEL A. ; MALDONADO, JESUS E.

WILSON JOURNAL OF ORNITHOLOGY

WILSON ORNITHOLOGICAL SOC

Año: 2009 vol. 121 p. 803 - 807

1559-4491

We Studied breeding biology, parental roles, and social mating system of the Bay-capped Wren-Spinetail (Spartonoica maluroides), a habitat specialist furnariid, in the Argentinean pampas. We found 42 nests during 2004-2007, two during egg laying, 28 during incubation, and 12 with nestlings. Mean clutch size was 3.17 eggs (n = 29), the incubation period was 13 days, and nestlings remained in the nest for 12 days before fledgling. Bay-capped Wren-Spinetails are socially monogamous; both males and females develop a brood patch and contribute to incubation, brooding, and provisioning of nestlings. Wren-Spinetails are unique among furnariids as they build an open CLIP nest with a few presenting a loose domed roof. Breeding success of Bay-capped Wren-Spinetails was higher (total probability of nesting success = 0.508) than other species of sympatric passerines because of low nest predation and high nest survival rates during incubation and nestling rearing stages.