Should be clarified here that there IS A DISTINCT DIFFERENCE between the Western Coyote and
what has evolved over the last 30 years to be the Eastern Coyote.
Western coyotes are typically in the 18-25# range (I know, they look bigger but it's all hair),
and the Eastern coyote can run 25-45#+, and is a larger, much sturdier critter. The
jaw of the Eastern coyote is stronger, and much more "squared" off, and they can
be more aggressive than their Western cousins. Eastern coyotes also tend to run in
packs more than the Western ones.
This time of year (nationally) coyotes are having pups, meaning the odds
of seeing "packs" later in the Spring/Summer is a real possibility. The pups, as they
grow tend to hang out together and can range quite a ways from the den, and
just 2 or 3 of them can sound like 50!
The Western coyotes will generally "disband" about late Sept., however the Eastern
dogs seem to remain in more of a family (wolf style) pack, and their added size and
aggressiveness makes makes them a much more dangerous critter to deal with than
their Western relatives.
Why did the coyotes more eastward and get bigger, more aggressive? Odds are high
that it's due to the overpopulation of the Whitetail deer in the Northeast.