Because seeds deteriorate and lose their nutritive value over time, try to plan so that you use up wild bird seed within a few months of purchase. Keep the seed supply cool and as dry as possible. Damp seed becomes moldy and unfit for birds.
Plastic or galvanized metal garbage cans are perfect for storing large quantities of seed, because they have tight-fitting lids that deter squirrels. Be aware, though, that raccoons have learned how to open tight garbage can lids. If squirrels are a pest in your yard use metal cans that they can not chew through. Place heavy logs, rocks or cinderblocks on the lids to keep animals from removing them.