The only time I have ever heard a coyote yipping has been after it was intruded upon. I heard a coyote yipping, the same coyote, both yesterday and again today. The yipping is a distressed, high-pitched barking. It may go on for 20 minutes or more. It appears to be the coyote’s way of complaining. In the parks where I have heard it, it always has been caused by a dog. A dog had either chased the coyote, or came in too close to it. A human intrusion, such as throwing stones to ward it off, could possibly cause the same barking reaction from a coyote, however, a coyote is more likely to flee this scenario. By yipping, the coyote is both voicing its discontent and standing its ground, albeit at a distance, as far as I have seen. Please keep your dogs leashed when a coyote is around.
And now I’m seeing coyotes react to individual specific dogs walking about 100 feet away. These are usually dogs which have chased or intruded on the coyote in the past. But also, now, I’m seeing that a coyote will feel intruded upon if specific dogs “eye” the coyote on its perch — possibly in an antagonistic way — something like giving the coyote “the evil eye”. In addition to the complaining and standing up for itself which I’ve seen when a dog actually chases it, the coyote’s barking may also be voicing its territorial claim.
I know a number of people who think, “Well, it’s a coyote and that’s what they do: they yip.” However, there is always a reason for the yipping; it never occurs without cause.
Coyote Yipps 
