This male Chaffinch clearly has a hugely swollen chest (it was even more apparent from the side but I could get a shot side on). The swelling could be due to one of several different reasons in the chest, but an internal tumor is a strong possibility. Strangely I had an even odder bird (
see here) with a massively deformed head in March 2009. Is there something wrong with my Chaffinches?
© Steve Dudley