10 ARTICULOSIndice <strong>de</strong> Diversidad (D) Abundancia totalIndice <strong>de</strong> Homogeneidad (E) Riqueza avesFigura 1: Indices Comunitarios <strong>de</strong> avifauna <strong>de</strong>l Monumento Natural El Morado, Región Metropolitana, en 4 períodos <strong>de</strong>muestreo. Se indica la abundancia total, Riqueza y los Indices <strong>de</strong> Diversidad y Homogeneidad <strong>de</strong> Simpson.N O <strong>de</strong> IndividuosFigura 2: Abundancia estacional <strong>de</strong> las especies más frecuentes y abundantes <strong>de</strong> aves en el Monumento Natural El Morado,Región Metropolitana. (Abreviaturas <strong>de</strong> las especies: Pauri = Psilopsiagon aurifrons; Grufi = Geositta rufipennis; Malbi= Muscisaxicola albilora; Sauri = Sicalis auriventris; Zcape = Zonotrichia capensis; Pgayi = Phrygilus gayi; Puni =Phrygilus unicolor; Curo = Carduelis uropygialis).
Boletín <strong>Chileno</strong> <strong>de</strong> Ornitología 11: 11 - 17Unión <strong>de</strong> Ornitólogos <strong>de</strong> Chile 2005ARTICULOS11NEST SUCCESS OF OPEN-CUP NESTING BIRDS IN CHILEAN RAINFORESTÉXITO REPRODUCTIVO DE AVES CON NIDO ABIERTO EN EL BOSQUE TEMPLADO LLUVIOSO CHILENOMARY F. WILLSON, TONI L. DE SANTO, KATHRYN E. SIEVING, AND JUAN J. ARMESTOMARY F. WILLSON5230 Terrace Place, Juneau, AK 99801, U.S.A. mwillson@gci.netTONI L. DE SANTO127 Sixth St., Douglas AK 99824, U.S.A.KATHRYN E. SIEVINGDepartment of <strong>Wildlife</strong> <strong>Ecology</strong> <strong>and</strong> <strong>Conservation</strong>, University of Florida,303 Newins-Ziegler Hall, Gainesville, FL 32611-0430, U.S.A.JUAN J. ARMESTOCenter for Advanced Studies in <strong>Ecology</strong> <strong>and</strong> Biodiversity, P. Universidad Católica <strong>de</strong> Chile, Santiago, ChileABSTRACTBetween 1993 <strong>and</strong> 1999, we monitored nest success of open-cup nesting species in fragmented <strong>and</strong>unfragmented temperate rainforest <strong>and</strong> in associated shrubby vegetation of fencerows, roadsi<strong>de</strong>s, <strong>and</strong> pastures,on Isla Gran<strong>de</strong> <strong>de</strong> Chiloé in south-central Chile. Daily nest survival rate in forest was estimated to be 0.964by the Mayfield method, marginally higher than in shrub habitat (0.945). Predation accounted for mostnest losses in forest, but both predation <strong>and</strong> parasitism by Molothrus bonariensis led to failure of nests inshrub habitat. Nest success of three common species was low (20-30%). Negative effects of forest edge onapparent nest success were small for Turdus falckl<strong>and</strong>ii <strong>and</strong> Sephanoi<strong>de</strong>s sephanoi<strong>de</strong>s, but apparently moremarked for Elaenia albiceps. Levels of predation during the nestling <strong>and</strong> incubation phases were similar inforest fragments, but higher during incubation in continuous forest. Low rates of reproductive success infragmented forests could pose problems for maintenance of these ecologically important species in thisforest ecosystem.KEY WORDSforest fragmentation, nest success, edge effect, nest predation, brood parasitism, south-temperaterainforest, Elaenia, Turdus, Sephanoi<strong>de</strong>sRESUMENEntre 1993 y 1999, estudiamos el éxito <strong>de</strong> los nidos <strong>de</strong> las especies <strong>de</strong> nido abierto en bosquesfragmentados y continuo <strong>de</strong>l bosque lluvioso templado y en la vegetación arbustiva asociada a cercos, bor<strong>de</strong>s<strong>de</strong> caminos, y pastos, en Isla Gran<strong>de</strong> <strong>de</strong> Chiloé en el centro sur <strong>de</strong> Chile. La tasa diaria <strong>de</strong> la sobrevivencia <strong>de</strong>los nidos en el bosque fue estimada en 0.964 por el método <strong>de</strong> Mayfield, marginalmente superior que en elhabitat <strong>de</strong>l matorral (0.945). La <strong>de</strong>predación explicó la mayoría <strong>de</strong> las pérdidas <strong>de</strong> los nidos en bosques, perola <strong>de</strong>predación y el parasitismo por Molothrus bonariensis contribuyó al fracaso <strong>de</strong> los nidos en el habitat <strong>de</strong>lmatorral. El éxito <strong>de</strong> los nidos <strong>de</strong> tres especies comunes fue bajo (20 - 30 %). Los efectos negativos <strong>de</strong>l bor<strong>de</strong>