They might look like hummingbird but they might be Hummingbird moths

One of my friends who says that he has been seeing hummingbirds before I saw them August 21, said he quite possibly has been seeing hummingbird moths, which are quite big and mimic hummingbirds. I have heard of them but I don't think I have seen them . What have been seeing are definitely hummingbirds.

In any case, here is a good website on these moths, what they look like and photos. Maybe you have seen them.

http://www.birds-n-garden.com/hummingbird_moths.html