Birds Do It...

With apologies to Cole Porter, sex is one of the major driving forces in nature. I was lcky enough to stumble upon two sets of tree swallows mating on two separate days.

On the second day, I was able to observe more of the process:

After copulation, the male flies off briefly...

Hwever, he's soon back...

After copulating a second time, he flies away again...

But, he's back again...

He approaches to copulate again.

At the end, the male is too tired to do much flying for awhile.