I have heard others comment on the ability of coyotes to distinguish long arm silhouettes. Apparently crows can do the same.
Crows and coyotes are some of the smartest species in NA. These 2 very different species are only a handful of all that have increased their population and territory against human encroachment. We have plenty of coyotes around here and they never cease to amaze how smart they are and how they learn and adapt from their mistakes. It is not often that anyone can fool a coyote...and very very rarely twice.
I have never seen coyotes that look like they would threaten a human adult, however if a few young coyotes get in a pack, they as Canoedogs said, get a little bit braver and if you have small animals or children, precautions are recommended no matter how remote you may think the threat is.
One good thing (depends on your view) coyotes around here have a knack of keeping the local and very annoying stray cat population in check. Just a couple of weeks ago, my SIL seen a coyote trotting along the street (and presumably home) with a cat in it's mouth....
Flip side of the coin, when living up northern Canada and in a small rural area, we went through a few cats that we deduced was due to the local coyote population. After about the 3rd cat going AWOL, we gave up keeping this type of family pet...
As for crows, they are almost a nuisance around here, yet I like observing these smart and clever birds as they go about their daily lives in the park nearby. If you are ever out hiking, you may be followed a crow or 2 as they are smart enough to know that people = a possible food handout source.