Someone mentioned hummingbird moths the other day but I can't find the post.
A couple of nights ago we saw a very large moth constantly dancing around
our poppies (this was probably close to midnight, out for a walk). He sure
looked like a hummer, never resting, always fluttering. After watching him
for quite a while, I got the camera - and he didn't leave! So, for those in
the know, is this a hummingbird moth?

http://home.earthlink.net/~beth.peace/moth.html