Browsing by Author "McGehee, Steven M."

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    Dinámica estacional y patrones de distribución de la avifauna asociada a humedales subantárticos de la Reserva de Biosfera Cabo de Hornos (54-55ºS), Chile
    (2009) Ibarra Eliessetch, José Tomás; Rozzi, Ricardo; Gilabert, Horacio; Anderson, Christoper B.; McGehee, Steven M.; Bonacic, Cristián
    El rol de las aves en la ecología de los ecosistemas subantárticos de la Reserva de Biosfera Cabo de Hornos (RBCH), Chile, ha sido poco estudiado. Se estudió el efecto de la altitud, distancia al borde costero, tamaño del espejo de agua, estación del año y cobertura vegetacional sobre la diversidad y abundancia de aves de humedales y de sus hábitats adyacentes en isla Navarino (54–55ºS, 67ºW) en la RBCH. Se cuantificó la composición específica, riqueza de especies y abundancias relativas de aves de humedales y de sus hábitats adyacentes, de manera estacional. Se registró un total de 56 especies pertenecientes a 10 órdenes y 25 familias, con una marcada estacionalidad en riqueza (P = 0,001) y número total de individuos (P < 0,01). De ellas, 33, 9% fueron residentes, 48,2% llegan en primavera-verano y para un 17,9% se desconoce su estacionalidad. La distancia a la costa marina es la variable que mejor explica tanto la riqueza (P < 0,01) como el número total de individuos (P < 0,05). Humedales a mayor distancia de la costa y altitud, presentaron menor diversidad de aves, a pesar de que los cambios en altitud fueron bajos (<300 m). Este trabajo muestra los patrones de estacionalidad y dinámica, así como los mecanismos subyacentes, de la avifauna de humedales y sus hábitats adyacentes en la RBCH. Aceptado el 20 de Mayo de 2009
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    Seasonal dynamics and distribution patterns of birds associated to sub-Antarctic wetlands in the Cape Horn Biosphere Reserve (54-55°s), Chile
    (NEOTROPICAL ORNITHOLOGICAL SOC, USGS PATUXENT WILDLIFE RESEARCH CTR, 2009) Ibarra Eliessetch, José Tomás; Rozzi, Ricardo; Gilabert P., Horacio; Anderson, Christopher B.; McGehee, Steven M.; Bonacic Salas, Cristián
    Seasonal dynamics and distribution patterns of birds associated to sub-Antarctic wetlands In the Cape Horn Blosphere Reserve (54-55 degrees S), Chile. - Little is known about bird ecology in sub-Antarctic ecosystems of the Cape Horn Reserve (CHBR), Chile. We examined the role of altitude, seashore distance, lake size, season, and vegetation cover in affecting bird diversity and abundance on Navarino Island (54-55 degrees S, 67 degrees W) in the CHBR. We determined avian community composition, species richness and relative abundance for wetlands and their adjacent habitats on a seasonal basis. A total of 56 species belonging to 10 orders and 25 families were recorded, and significant seasonal changes for bird species (P = 0,001) and abundance (P < 0,01) were observed, with 33,9% residents, 48,2% winter migrants, and 17,9% With unknown migratory status. The distance of wetlands from the coastline was the main predictor variable for annual species richness (P < 0,01) and total avian abundance (P < 0,05). Wetlands far from the seashore and at higher altitudes had lower diversity and abundance, although the change in elevation was relatively slight (< 300 m). These data show the seasonal patterns and dynamics, as well as the major underlying mechanisms, for birds of wetlands and adjacent habitats in the CHBR.
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    Using molt limits from mist netted birds to age Southern Hemisphere passerines on Navarino Island, Chile
    (2006) McGehee, Steven M.; Ibarra Eliessetch, José Tomás; Rozzi, Ricardo
    Omora Foundation NGO has been conducting a program of capturing and banding passeriformes of the Magellanic subantarctic forests for the last seven years in Omora Ethnobotanical Park. In order to study age related differences in reproductive success, survivorship, habitat selection etc., easy and accurate methods for determining the age of a bird in the hand are needed. For most Austral South American species this method has yet to be worked out. Here we report on the results of capturing and banding 6702 birds of 21 different species supplemented with information obtained from bird skins in museums in Chile. Data from the extent of the prebasic molt in known aged birds has allowed us to identify the extent of some molt limits in 7 species of 4 families of passerines (_Anairetes parulus_, _Tachycineta meyeni_, _Turdus falcklandii_, _Phrygilus patagonicus_, _Melanodera xanthogramma, _Curaeus curaeus_, _Carduelis barbata_).