Excellent Nature Photography Site

I recently took some wonderful photography classes with 

photographer Valerie A. Hoffman 

(she is on facebook) and she sent me a link to an excellent ebook offered by this

nature photography site which I have found very helpful.  

I enjoy shooting birds, and this site offers 

great advice: http://www.naturephotographysimplified.com/ 

and amazing images, such as this one: 

Here are some other helpful sites:

http://www.naturephotographers.net/birdphotography.html

http://www.digitalbirdphotography.com/contents.html