The following Web sites contain a wealth of great information about wild birds and bird feeding.  We recommend that you visit these and bookmark them for future reference.
SEED AND GRAIN DESCRIPTIONS

Black Oil Sunflower - A large seed, black in color, which has a hard outer shell and a soft inner meat that is relatively high in protein and very high in fat cont...

PROTECTING YOUR BIRDS
Aflatoxin in Bird Seed Mixes WHAT DO WE KNOW ABOUT AFLATOXIN? - Aflatoxins are produced by fungi that are common and widespread in nature, Aspergillus parasiticus and A. flavus. -The fungi grow...