All coyotes will howl, not always, but they all will sometime. This last weekend, while calling with Catmandoo, we heard a lone howl, I'm sure it was the male of the pair, but, as I just said, when we moved in and called them, a pair came, where as the male was the only one that we heard howl. There are many different vocalizations that coyotes use, including female and young males. My favorite two methods of using the howl to call coyotes is 1) do 2 or 3 lone or greeting howls, then sit silent for around 5 minutes, if no coyote answers or shows up, then go into rabbit squeels. Just because we howl and we get no response doesn't mean that there aren't any coyotes that heard us, but now they no that there is a stranger in the neighborhood. And with the combo of a couple howls then silence then rabbit, they often will come on in. 2) coming into the mating season, lone howls will often work by itself, and if one challenge bark howls back, now challenge howl bark at it. Don't over call, but do it a couple of times then wait, if the coyote doesn't show up in 5 to 10 minutes, do it again. If you're up against the dominant male, he will probably show up, looking to kick some butt. Howling is the most difficult calling method to master. Rabbit squeels can sound about like any thing and bring a coyote in, but if you are using howling and say the wrong thing, it's over before you know it and that is why I say not to over howl. All you really need to do is to convince them that there is a stranger around. You don't have to howl much to do that.