Here are two sites that provide links to other sites. Both sites have categories for birds.
The text on this site is in English:
Free Paper Toys, Paper Models and Paper Crafts at ss42.com
The text on this site is in Japanese:
00 インデックス
but there are thumbnails indicating the types of paper models available. There are some links with a line through the name indicating that the link is broken and will not work.
