Has anyone else experienced their feral colony taking to the trees?

My colony's feeding station is under a thick bramble bush which is
sheltered by a healthy fir tree that extends up 35-40 feet in the air.
It's at the edge of an industrial campus parking dotted with lots of
much smaller (though currently heavily foiliaged) liquid amber trees
which average 12-25 feet tall.

I have arrived recently to find cats inhabiting *seriously* astonishing
high levels of the fir tree, heights from which they seem to descend
fairly well; not as agile as squirrels, but still doing much better than
I would have thought.

I witnessed at least one fight involving three cats in the branches of
one of the nearby liquid amber trees, and I have personally seen cats
coming down out of the liquid amber trees to feed at the station when I
come (usually at or just after dusk).

These ferals are rarely if ever seen by the workers in the daytime. Is
it possible that they are living in the trees? This cannot be a good
thing for birds, if so. Still, what a great hiding place for the cats.
Who looks up into branches to see cats? Jeez, they never cease to amaze
me, these animals.