lunes, 1 de septiembre de 2008

Argéntea (3)

Voy a pegar algunos comentarios que he recibido Y para complementar la descripción de la argéntea en este blog, colgaré en la cuarta entrega unas fotos enviadas amablemente por Ruud Altenburg, que ilustran a la perfección el parecido de la gaviota de Colmenar con otros juveniles de argéntea anillados en los Países Bajos.

Mi agradecimiento a Roland-Jan Buijs, César Álvarez, Dani López, Peter Stewart, Rafa Salvadores, Ruud Altenburg, Philippe Dubois, Nacho Vega y Alfonso Rodrigo por sus comentarios y aportaciones, esenciales para identificar con cierta seguridad esta gaviota.

"looks like a good juv. Herring gullThe pattern of the tertials, inner primaries and GCs, the lack of an obvious eye mask as well as the mainly juvenile scapulars in September eliminates michaellis" (Dani López)

"For me it is Larus argenatus (Herring Gull), I ringed more than 5.000 big juvenile Herring gulls and this bird is very common to argentatus, also according to moult!" (RJ Buijs)

"Looks like a HG for me" (Peter Stewart)

"I agree with Ruud, saying that it strongly looks like a 1cy Herring Gull. Idon’t mind about head moulting and birds from Brittany are often like thatby the end of August (and recall that this bird is in Spain, a rathersouthern locality for HG). But it is right to try to exclude definitely anYLG, since when seeing its open wings, there is not a clear indication of “window” on inner primaries. All in all, this bird looks like a rather typical HG" (Philippe Dubois)

"I guess it's difficult to compare moult when birds are moulting slower than average. If it had replaced some coverts this would have been a strong pointer for YLG but when it doesn't this doesn't automatically mean it's likely to be a Herring. Still it looks rather fresh for a bird at the end of August, which actually is a good pointer for Herring, as are the barred greater coverts, the paler inner primaries and densely patterned undertail coverts. For our standards it's a bit early in moulting its head feathers but I guess that more southerly populations start earlier with the post juvenile moult" (Ruud Altenburg)

"interesante dato que da Ruud, que ya hay Argénteas sureñas mudando escapulares. Entonces sí que tu bicho tiene más posibilidades de Argéntea que de Patiamarilla" (César Álvarez)

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