There were 4 (maybe 5) Great Black-backed Gulls mixed in with a few 
Herring Gulls and lots of Ring-bills yesterday just downstream of 
Violette's Lock. Also some Common Mergansers. 

Other highlights

Riley's Lock:
Pied-billed Grebe
Ring-necked Duck 12
American Wigeon 40+

end of Sycamore Landing Rd:
American Black Duck 2
Common Goldeneye 13
Bufflehead 15
Barred Owl 2 (heard)
Red-breasted Nuthatch

Hughes Hollow:
Hooded Merganser 6
Ring-necked Duck 2
Wood Duck
American Wigeon (heard)
Red-tailed Hawk (perched on cell phone tower)
Barred Owl (heard)
Eastern Phoebe (seen on 2/18)
Winter Wren
Red-winged Blackbirds staking out territory

Also, great looks at an otter feeding near the island in the large 
impoundment.

Andy Martin
Gaithersburg