After stumbling on to a pileated woodpecker excavating a cavity in late
March, I returned this week and got to see a nestling head poking out of
the cavity.  The entrance to the cavity has that fresh look of recently
chiseled wood, plus the bottom edge is beveled.  With that search image in
mind, I was able to locate a second cavity of similar size that is also
beveled on the lower edge of the entrance.  Visiting that second cavity
this evening, I saw 3 large nestling heads sticking out as an adult male
fed them.

Based on my limited experience, that beveled edge may be a distinctive
feature of pileated nest cavities.

Tim Ray
Columbia MD