September is a great time to visit the Florida Keys because the heat is manageable. We spent most of our time in Key West and Big Pine Key. Key West has a fascinating history. You can find out about it here. The architecture is really amazing and it is fun to see fall decorations up in people's front yards, they seem so out of place in such a tropical environment.
chickens running around all over Key West, causing a lot of controversy. They were brought by early settlers and they are protected (so don't mess with them), but now the city wants to get rid of them. I personally think they add charm, but I can also see how you wouldn't want chicken droppings all over your property.
Key Deer are prolific. They are endangered and you aren't supposed to feed them but people do anyway and they will come right up to your car to beg. This isn't the best picture, I took tons and I can't find them all right now, but you get the idea.