Folklore says that coyotes howl at the full moon, but it turns out they're more particular than that.
Coyotes (Canis latrans) use three different types of howls: lone, group and group-yip howling. For the iconic lone howl, the phase of the moon makes no difference.
But, contrary to mythology, the other kinds of howls are more frequent when there's no moonlight all.
The group and group-yip howls are used to lay claim to territory, and so it could be that the reduced visibility of the new moon means coyotes have increased need for territorial defense.
Another explanation could be that under low visibility coyotes prefer to hunt larger prey. Such a strategy would require group hunting and thus increased communication.