Have a wee look
here. The first list is birds that you would be best to avoid having in your possession and the remainder would be OK, assuming they were shot in the right season. In fact, I am always surprised at some of the species you can still shoot (ptarmigan and goldeneye, for example).
Note that all birds are protected during their breeding season, including 'pest' species, so crows, for example, must not be shot when nesting. But as soon as the fledgling steps from the nest . . . .
Obviously the spirit of the law is to protect certain bird species especially, which is only fair and right, and I think any reasonable human could respect that.
At the end of the day though, detection would be nearly impossible and prosecution very unlikely. I think its just a case of being sensible and there is plenty of roadkill to be had. With the plethora of materials and dyes that exist how much more do we need?
A