Wildlife Art News (monthly magazine) generally lists all the deadlines and
requirements for all the various contests in at least one of the issues - I
don't remember which. They also have a listing of wildlife art shows and other
events. The magazine is a bit pricey (I don't subscribe anymore) but it's a
good source for that sort of info. I would be surprised if they didn't have a
website, although I have not looked for it myself. One thing I do remember
about state contests - for some of the states you must be a resident of that
state to enter - that varies from state to state though.

Liz Hansen
Sketchbook Graphics
and
Sr. Illustrator - Center for American Archeology