To add to Jim Boughton's directions:

From the interchange of US 340, Rt. 9, and Rt. 51, go about 3.3 miles to Augustine Avenue.  Take a sharp right onto Augustine Avenue.  Take the second left onto Prospect Hills Blvd.  At the circle/obelisk, go right onto Butler Street.  At the next circle, go 3/4 of the way around circle, taking the first right (Colston Road).  You will see the pond on your right a little ways ahead.  

The bird sometimes walks up the bank and disappears, resting.  Its color is similar to the soil color on the bank and it can be hard to find.  It's a handsome bird and hopefully there will be on in DC or Montgomery County soon.  

Rob Hilton
Silver Spring