Coyotes are amazing, aren’t they? One of the reasons that they have been so successful living around humans is that they can adapt to all sorts of conditions. They live in many different climates. They can live off of all kinds of food, including small mammals, birds, large insects, nuts, and fruits. I have even heard that when the sugar content in grapes is at its highest, they eat a lot of grapes at vineyards. If you live near a park, cemetery, or other “green space” that provides food and shelter, that may be why they like your neighborhood.

In the wild, coyotes have to be on the lookout for larger predators, such as wolves. So their ancestors developed behaviors (like hiding and avoiding) long ago. Most wild coyotes are active during the day (diurnal) or right around sunrise and sunset. Where humans are active, coyotes may go on the night shift. I live in a suburban neighborhood and never see coyotes during the day, but have seen them at night. That doesn’t mean that the coyotes you saw were rabid or dangerous. Their behaviors are flexible. If being out during the day is working for them, they may stick with it.

People might live right in coyote territory, but never see an actual coyote. They might hear them though. Coyotes tend to live alone or in small family units. These families often start the night with choruses of howls or high-pitched yipping. They can be pretty noisy. I have heard them several times while camping or backpacking. Urban coyotes are usually quiet. However, one time I was walking near a wooded area in town and an emergency vehicle went by with its siren on. A whole family of coyotes joined in the noise.

You may want to check out this site about urban coyotes. Behavioral ecologists get to spend their working lives studying what animals do and why they have those behaviors. That might be a career for you.

The wild coyote is EXTREMELY adaptable always making changes to deal with external environmental factors. In Nature far away from human activities, they tend to be most active and dawn and at dusk. This is when a lot of their prey is active.

Coyotes are diurnal in their natural habitat. However, recently scientist has observed that in order to avoid human, pumas, bobcats, and coyotes in the Santa Cruz Mountain have become more active during the night. (Please link to this site. )

I believe that coyotes are largely diurnal, but there is evidence to suggest that some have become nocturnal to avoid conflict with other animals (particularly people). Dogs see better by day than by night, but are still capable of seeing at night. In any case, seeing coyotes active during the day is not unusual activity for coyotes. Since you haven't told me where you live, I can't comment on whether coyotes are normal for your area or not, but I can say that coyotes are extremely versatile animals that live throughout much of the drier parts of the United States.

I’ll attack your questions in order:

Coyotes are mostly diurnal, most active at dusk and dawn, but can trend to nocturnal habits if their habitat is near humans, which affects their circadian rhythm (the natural cycling of their awake or asleep states).

Coyotes can venture out during daytime to search for food as they are opportunistic hunters of small wildlife, e.g. rodents. Further, this particularly bold behavior by coyotes does not necessarily mean they are sick, but caution should always be practiced and contact the local animal safety authorities if concerned.