I've had the exact same problem, so determined to find this mystery 
great crested i search my yard extensively. After a half hour i did 
find a northern mockingbird doing a fantastic impression of both a 
Great Crested, and what sounded similar to a brown thrasher.
On Feb 25, 2005, at 11:22 PM, Janet Millenson wrote:

> Kevin Caldwell wrote: "I'd swear to all ends that I'm hearing a great
> crested flycatcher around my home, but don't think they could be here 
> and
> calling this early."
>
> Kevin, I had the exact same experience a few years ago. The apparent
> out-of-season flycatcher turned out to be a very talented mockingbird.
>
> Janet Millenson
> Potomac, MD (Montgomery County)
> 
> ----------------------------------------------------------------
> "Look at the birds!" -- Pascal the parrot
>