Sánchez-Alonso, C., Ruiz, X., Blanco, G., & Torre, I. (1996). An analysis of the diet of Red-billed Chough Pyrrhocorax pyrrhocorax nestlings in NE Spain, using neck ligatures. Ornis Fennica, 73(4), 179–185. Retrieved from https://ornisfennica.journal.fi/article/view/133451