While I was looking for information to help identify the wing of a bird I found a very interesting site. The McGill Bird Observatory. It's in Canada and is a work in progress compiled with information gathered while banding birds. Not at all complete as yet but some great info on sparrows & Purple Finches - since many of us have a hard time identifying them! Many other birds as well.
The site has pictures of birds at various ages and pictures of many wings & tail feathers. If I remember correctly, I believe they rely on pictures sent in by banders.
http://www.migrationresearch.org/mbo.html
Vicki Conklin
