Observing two black vultures touching beaks and acting all lovey-dovey on my back deck recently, I came to ponder on sex among avian creatures. It is an interesting topic.

Some ten percent of all birds are monogamous, having only one mate. However, like their human counterparts, some birds do fool around.

Swans and albatrosses display a high level of fidelity and often form lifetime bonds. However, many songbirds have a new mate every year.

Also, when it comes to sex, most birds do not go in for ...