Hi Gail,
Here's a link to a list I found through google using this:
fiction characters birthdays
http://www.gaiaonline.com/forum/anime-manga-comics/is-the-birthday-for-your-favorite-fictional-character-here/t.44158895/
It's got Winnie's B-day and several others
Best,
Ed Rossman
Libraries Rock!
http://www.castles411.com