For those of you in the United States and Canada, I found this site to track the hummingbird migration for 2009.
I do not have an official map from the AARP, but I think the retirees heading north from Florida should be following roughly the same migratory patterns. We have found that if you feed them, they will stay for approximately 48 hours; then they start checking the Weather Channel for good driving conditions.
The butterflies cannot be far behind. Happy Spring, everyone!