Bird data was provided by J. Carnicer, L. Brotons. Data collection was organised by Institut Catal`a d'Ornitologia. If you use this data, please cite:

J. Estrada, V. Pedrocchi, L. Brotons, S. Herrando, Atles Dels Ocells Nidifi- cants de Catalunya 1999–2002 [Breeding Birds Atlas of Catalonia]. (Institut Catal`a d'Ornitologia/Lynx Editions, Barcelona, 2004).

J. Carnicer, L. Brotons, S. Herrando, D. Sol, Proceedings of the National Academy of Sciences 110, E2858 (2013). Https://doi.org/10.1073/pnas.1222681110.
