It is quite possible that is what you heard. Whatbird.com is a great web site that is easy to navigate and covers just about every bird. It also has a sampling of sons and calls for each species. Keep an eye out for that bird and hopefully you'll be able to confirm your sighting! But when it sits still, you probably won't hear it utter a sound, and they can be very good at blending into their surroundings.
From: Jeremy Smalley <[log in to unmask]>
To: [log in to unmask]
Sent: Sun, 3 May 2009 9:06 pm
Subject: Re: [VTBIRD] Possible Black-crowned Night Heron
Around 7:00 tonight we heard a strange call, almost like a bark, coming from a
group of black locust trees near our house. The trees are about 200' from a
large swamp. We got a quick look and then it flew over our house (away from the
swamp) and landed in a group of trees about 400' from the house. After looking
at our bird guides and a CD of recordings we think that it was a black-crowned
night heron. It would be a life bird for me and my dad.