This was taken a few weeks ago at Saltholme Marsh. The bird was at a feeding station where all the feeders had been removed. When I asked why the feeders had been removed and why the finches looked puffed up I was told they had Trichomoniasis (Canker).
The feeders are taken away to control infection. The infection causes lesions in the throat of infected birds making it difficult for them to swallow. Therefore if the try to feed they spit out the seed, which is then contaminated by the infected birds saliva. This seed may then be picked up by other birds, therefore spreading the disease.
Sadly, infected birds die, but hopefully the removal of the feeders will have saved some of the others from a similar fate.
Thanks for looking.