If a coyote is visiting your yard, that means he has habituated to people and, yes, you should be concerned.
The smaller the dog or child, the more likely the coyote will see it as prey. As a rule of thumb, dogs that are 40 pounds or more are less likely to be attacked. Cats are a preferred food of the coyote.
Putting food and water outside will increase coyote traffic (not to mention rats, raccoons, oppossums, etc.). Do not leave food for your pets outside, and ask your neighbors not to leave food out. Secure your garbage cans. Making food available is inviting the coyote to move in.
Fencing at least 6 feet high and secured to the ground will discourage coyotes.
Are coyotes hunted and trapped in your area? It appears that areas where hunting and trapping have been banned or severely restricted experience increased likelihood of coyotes losing their fear of humans.
Wild animals also pose other threats besides physical injury, such as carrying diseases, ticks, and fleas.
More information can be found at Coyote Information.
