Nationwide UK areas vary but in Manchester out of normal working hours the police (via a phone call to their working number NOT 999) will issue a FWIN for an injured stray or wild animal but the police have to ring a specific vet who they deal with to collect the animal and the vet will not accept FWIN numbers from members of the public. The vet then sends out a collection vehicle. During normal working hours if the animal is big or not handle able then the police will issue a FWIN but not for things like birds they can be taken by the finder to a local vet. You can try the rscpa and wait several hours for a harassed ACO but please do not have a go at the ACO for taking so long they are stupidly overworked and in our area l think at present 3 cover the whole of the NW full time. Vets in UK are legally obliged to provide first aid it even if that is just putting the injured animal down. I know some vets who will try and refuse to treat wild animals or injured strays but stamp hard on their necks and mutter rcvs disciplinary or local newspaper coverage that generally works.