Birds in Spain Blog

English abstract  below Censo de la población nidificante 2018 La gaviota de Audouin (Ichthyaetus audouinii ) ha intentado o nidificado históricamente en nueve localidades catalanes, de norte a sur:  PN Aiguamolls de l’Empordà, Alt Empordà, Girona (puestas sin éxito en 2009 y 2010) Puerto de Barcelona, Barcelonès, Barcelona (colonia activa) Zona Franca de Barcelona, Barcelonès, Barcelona (colonia urbana que funcionó en 2013) Delta del Llobregat, Baix Llobregat, Barcelona (nidificante entre 2009 y 2017) Puerto de Tarragona, Tarragonès, Tarragona (colonia activa) Delta de l’Ebre, Montsià, Tarragona. Colonias o casos aislados de nidificación en la Punta de la Banya y Salines de la Tancada, colonias activas, y en la isla de Buda, parejas aisladas en 2010-2011. Puerto de Sant Carles de la Ràpita, Montsià, Tarragona (nidificante entre 2011 y 2015). Figura 1. Colonias  históricas de I.audouinii en Catalunya [Colònies/indrets de cria de gavina corsa a Catalunya/ S

© Juanma Ferreira En castellano más abajo On 21 July 2018 a 'pale' Reed Warbler ( Acrocephalus scirpaceus) aged EURING 3 (born in 2018) was trapped and ringed at Algar river, Alicante (Toni Zaragozí, Juanma Ferreira, Paco Galindo). Its identification was straightforward thanks to biometrics and its structure and general shape. However, the bird was extremely pale, diluted, compared to a regular Reed Warbler (see enclosed photos). The bird presented a colour aberration in which apparently the pigments responsable for black coloration (eumelanins) were missing. Brown pigments were present (originated by phaeomelanins) and the regular eye colour discarded an albino, which would also present a full white coloration.  This pale bird would apparently be showing a 'brown' aberration. This colour variation is caused by a qualitative reduction of eumelanin. The whole amount of pigmentation does not change but 'black' is missing. A leucistic b