What are the reasons for white feathers in corvids?
A grounded premature rook or crow with white, brittle or partly broken wing and tail feathers needs expert and longterm care to allow the damaged feathers to be replaced during their annual moult. Birds affected should not be released before their complete annual moult, which happens for fledglings born this year in the summer of the following year. Otherwise it will be unlikely that these birds are going to survive their first winter, as the deficient plumage will quickly deteriorate further. This usually means that these birds will eventually become grounded. They will get easily wet and hypothermic, are prone to predation and will soon be unable to sustain themselves.
Poor plumage development in corvids, where birds are showing white and brittle feathers with multiple stress bars, can have multiple causes. Genetically caused plumage development problems are occasionally to consider, but are rather rare. These are usually not correctable, neither with a dedicated diet nor by an annual moult. However, there are at least three other more common causes to consider, which are frequently responsible for this problem. Please follow the link below to read the full blog post.