Well, it is just a guess...I can't think of any other bird that comes close
to that sound, and I'd put more weight on the sound more than the metadata.
Not having been in situ, it is hard to think about it. I could see the
possibility because "upper canopy" could gotten from an above-canopy flight,
and I have often seen nighthawks near water. Are there any open fields very
close by the site? On the other hand, perhaps there is a evolutionary
trend towards arboreal bullfrogs?

Lee Cain
Summer: lcain at seasurf.net
School: lcain at astoria.k12.or.us
Instructor, Aquatic Biology/Integrated Science
Astoria High School
Astoria OR 97103 503-325-3911 vm 216


----- Original Message -----
From: "Mike Patterson" <celata at pacifier.com>
To: <lcain at seasurf.net>
Cc: "tweeters" <tweeters at u.washington.edu>
Sent: Tuesday, July 17, 2001 8:39 AM
Subject: Re: Mystery Bird Call


> Daytime? In the canopy?
>
> Blue Grouse...
>
> > Lee & Lori Cain wrote:
> >
> > FWIW, Here's my guess:
> >
> > "Common Nighthawks ...are most commonly seen feeding high in the air
> > during the dusk and dawn hours. Like most other goatsuckers,
> > nighthawks feed on flying insects, but unlike most other caprimulgids
> > (e.g., poorwills) insects are captured or "hawked" during continuous
> > flight. Nighthawks are well-known for the non-vocal "booming" calls
> > which are thought to be produced by air rushing through the primary
> > feathers of males. These sounds are presumably used for courtship
> > display and territorial advertisement."
> >
> > from http://www.for.gov.bc.ca/RIC/Pubs/teBioDiv/poorw/goatml20.htm
> >
> > in my experience what is described as a "booming" IS more like a
> > bullfrog.
> >
> > Lee Cain
> > Summer: lcain at seasurf.net
> > School: lcain at astoria.k12.or.us
> > Instructor, Aquatic Biology/Integrated Science
> > Astoria High School
> > Astoria OR 97103 503-325-3911 vm 216
>
> --
> Mike Patterson Alas, to wear the mantle of Galileo,
> Astoria, OR it is not enough to be persecuted
> celata at pacifier.com by an unkind establishment,
> you must also be right.
> ---Robert Park
> http://www.pacifier.com/~mpatters/bird/bird.html
>