A: As far as I know, there is only one type. The birds that peck on the tress and annoy the hell out of me.
Oh, and there's also Jim Dale. I guess you could include him. He suffered a war wound in a very unfortunate area. Always a do-it-yourself kind of guy, Jim insisted on finding a way to satisfy his wife. So he built that contraption.
He claims she likes it. From what I hear, she complains a lot about all the splinters.