Help with woodpecker call

["John Carroll"]

If anyone out there has experience/knowledge about woodpecker calls I would=
 appreciate any comments.

http://soundcloud.com/dismalhiker/agitated-pileated-woodpecker

Yesterday I recorded the last 2 minutes of a 5 minute long Pileated Woodpec=
ker call, mixed with what sounds like a hawk (? Red-Tailed hawk).  The wood=
pecker sounded quite agitated, especially evident near the end of the recor=
ding.  The woodpecker is clearly aware of the hawk's presence and responds =
to it.  Any thoughts on this apparent interaction between the woodpecker an=
d the hawk?

I hear the Pileated Woodpecker almost every time I'm out hiking, but I've n=
ever heard it go on for 5 minutes continuously or sound so agitated.

It was a very windy day (tropical storm approaching), so the recording is a=
 bit noisy, with some EQ to lift the woodpecker out of the noise.  Location=
: Ouachita Mountains, central Arkansas.

Thanks in advance,
John