1. CEMFOR - CTFC; InForest Joint Research Unit; CSIC-CTFC-CREAF; Solsona 25280 Spain
2. CREAF; Cerdanyola del Vallés 08193 Spain
3. Department of Ecology and Evolution; University of Lausanne; Lausanne 1015 Switzerland
4. European Bird Census Council-Catalan Ornithological Institute; Natural History Museum of Barcelona; Plaça Leonardo da Vinci 4-5 Barcelona 08019 Spain
5. Institute of Earth Surface Dynamics, Geopolis; University of Lausanne; Lausanne 1015 Switzerland
6. CSIC; Cerdanyola del Vallés 08193 Spain