I had an interesting time birding between Blockhouse Point and Riley's Lock on the C&O Canal in Montgomery County this morning (roughly from mile marker 21 to 23).  

Highlights on the Potomac River were several flocks of Bonaparte's Gull, 3 Horned Grebe in various plumage stages, 2 Common Loon, a probable Caspian Tern (too far away and I had no scope), and lots of Double-crested Cormorants.    Barn Swallows and Tree Swallows were active over the River.  I saw 24 Common Merganser including the previously-reported female with young -- I counted 12 young as she scooted away with them, first all on her back and then swimming with her.  There was a large group of small, dark ducks along the Virginia shoreline.  Without a scope, I'm guessing they were lingering Ring-necked Duck.

Along the towpath, highlights included 2 Black-crowned Night-Heron near Riley's Lock, a Pine Warbler heard in the pine trees on the Bretton Woods golf course, and a very cooperative eastern Palm Warbler that foraged on the towpath ten feet in front of me.

Just above Violette's Lock, I  had a great, close view of a quiet perched Red-shouldered Hawk that suddenly swooped down into a dry, meadowy section of the Canal, caught some small mammal, and then returned to its perch to eat.

By sheer luck, at Blockhouse Point I noticed two Turkey Vultures on one of the rock outcroppings on the inland side of the Canal.  I would have missed them, but an Eastern Phoebe was flying back and forth in front of them, thus drawing my attention.  When I first saw them, I thought it was only one bird, sitting on a rock right above the water in the Canal.  But then I realized there was a second one inside a rather deep crevice in the rock face. That one seemed to be poking around in leaves and other debris rather deep into the rock.  After a couple of minutes, this one came out of the crevice, and the two birds jumped up higher on the rock and sat together.  Reading in The Birds of North America Online, I see that Turkey Vulture nest sites include crevices in rock outcrops.  So I wonder if this pair was exploring a potential nest site.

A complete list from my eBird report appears below.

Jim Nelson
Bethesda, MD

Location:     Violette's Lock
Observation date:     4/9/08
Notes:     Count of Common Merganser includes a female with 12 young.
Number of species:     45

Canada Goose     44
Wood Duck     2
Mallard     11
Bufflehead     2
Common Merganser     24
Common Loon     2
Pied-billed Grebe     11
Horned Grebe     3
Double-crested Cormorant     47
Great Blue Heron     6
Black-crowned Night-Heron     2
Black Vulture     1
Turkey Vulture     2
Osprey     1
Red-shouldered Hawk     1
Bonaparte's Gull     18
Red-bellied Woodpecker     8
Downy Woodpecker     9
Hairy Woodpecker     1
Northern Flicker     3
Pileated Woodpecker     1
Eastern Phoebe     5
Blue Jay     17
American Crow     5
Fish Crow     6
crow sp.     10
Tree Swallow     2
Barn Swallow     3
swallow sp.     2
Carolina Chickadee     23
Tufted Titmouse     11
White-breasted Nuthatch     8
Carolina Wren     17
Eastern Bluebird     3
American Robin     6
European Starling     9
Yellow-rumped Warbler     22
Pine Warbler     1
Palm Warbler (Yellow)     1
Song Sparrow     7
White-throated Sparrow     11
Dark-eyed Junco (Slate-colored)     19
Northern Cardinal     16
Brown-headed Cowbird     13
American Goldfinch     13