The web is enabling bird ringers to share their knowledge directly with each other. A couple of initiatives, although focused abroad, can be very useful to ringing in Britain.
A couple of useful resources are:
An ageing and sexing guide for birds of Aragon, Spain
Identification Atlas of Birds of Aragon
An ageing and sexing guide (primarily passerines) for the Scandinavian countries.
Ringers' DigiGuide
