Yet another "rights grab" photo contest, this from the National Wildlife Refuge Association. Sure it has a couple cash prizes, but they get free and unlimited rights to all submitted images, whether winners or not:
"...by submitting an image for entry in this contest, you automatically give NWRA permission and rights to store, display, and use the image, its thumbnails, and your name as the photographer, indefinitely in any media without notification or compensation."
e.g. they get their entire year worth of photography for the cost of a couple cash prizes (from their sponsors) and don't have to pay photographers for images.
Serious contests like the BBC or NWF contest only get rights to use winning images to help promote the contest, and pay for anything else they might want. That way they encourage photographers to submit commercially valuable images without fear of destroying their sales potential.