Breeding success and social mating system of the bay-capped wren-spinetail (Spartonoica maluroides).

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

WILSON BULLETIN

Wilson Ornithological Society

Lugar: Tucson, Arizona, USA; Año: 2009 vol. 121 p. 803 - 807

0043-5643

We studied breeding biology, parental roles, and social mating systemof the Bay-capped Wren-Spinetail (Spartonoica maluroides), a habitat specialist furnariid, inthe 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), theincubation period was 13 days, and nestlings remained in the nest for 12 days beforefledgling. Bay-capped Wren-Spinetails are socially monogamous; both males and femalesdevelop a brood patch and contribute to incubation, brooding, and provisioning of nestlings.Wren-Spinetails are unique among furnariids as they build an open cup nest with a fewpresenting 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 passerinesbecause of low nest predation and high nest survival rates during incubation and nestlingrearing stages.