Birds and the Bees

So I'm walking along the sidewalk in Brooklyn one afternoon and I see -- wait for it -- two birds having sex on the sidewalk. It occurred to me then that while several animals have a reputation for lustiness, that was the first time I'd seen two birds in the moment and frankly, despite the fact that "the birds and the bees" is a time tested euphemism for learning about sex, it doesn't make any sense. Shouldn't it be "the dogs" or something?

It being Brooklyn and all, I'm sure that wasn't the first time that spot on the sidewalk had been used for intercourse, but I can't help but think, maybe that was the first time birds had ever used it for such. What happened to their nest, anyway? I guess even birds need to spice it up every now and then.