BECAS
ECHAVE MarÍa Eugenia
artículos
Título:
Reducción de la supervivencia anual del Playero Rojizo (Calidris canutus rufa) en su escala migratoria de San Antonio Oeste, Argentina, por efectos dominó de llegada tardía y depresión del recurso trófico en Bahía Delaware
Autor/es:
GONZALEZ, PATRICIA; ALLAN BAKER; ECHAVE, MARIA EUGENIA
Revista:
El Hornero
Editorial:
Asociación Ornitológica del Plata
Referencias:
Lugar: Buenos Aires; Año: 2006 vol. 21 p. 109 - 117
ISSN:
0073-3407
Resumen:
Ecological conditions in breeding and non-breeding areas of migrant birds have been linked to their annual survival and production of young, but the role of stopover sites is under-appreciated. Through banding studies and censuses along the flyway from Tierra del Fuego to the Canadian Artic, the drastic decline in 200-2001 of Red Knots (Calidris cannutus rufa) population summering in southern South America in the northern winter zas shown to be related to the overharvesting of horseshoe crabs ( Limulus polyphemus) in Delaware Bay, USA, their last stop-over site before reaching their breeding grounds, and to the late arrival of the birds at this site. In San Antonio Oeste, Argentina, where 25-50% of the Tierra del Fuego Red Knots population congregates every northward migration season, annual survival of the cohort of experienced birds banded in March 1998 was impacted a year later than the general decline. Knots marked at San Antonio Oeste earlier in March arrived in Delaware Bay on average before those marked 15 days later. Additionally, early migrating knots with active body moult in San Antonio Oeste exhibited a higher return rate in the following years than late and non- moulting birds. Since the decline, birds arriving late in Delaware Bay have been al increased risk of not being able to refuel properly or on time because food is no longer superabundant at that stopover site. These domino effects indicate that there are fitness consequences to individual migration strategies adopted by birds at austral summering and stopover sites, which can be amplified by compressed timing in Delaware Bay when food is depleted at this final stopover site.
