https://www.bto.org/our-work/science/publications/papers/decline-bullfinch-pyrrhula-pyrrhula-britain-mechanism
The decline of the Bullfinch Pyrrhula pyrrhula in Britain: is the mechanism known?
The decline of the Bullfinch Pyrrhula pyrrhula in Britain: is the mechanism known?
Citation
Siriwardena, G.M., Freeman, S.N., & Crick, H.Q.P. 2001. The decline of the Bullfinch Pyrrhula pyrrhula in Britain: is the mechanism known?. Acta Ornithologica 36: 152.
