field_report from "Pennyfield Lock" on 05/05/2007 - 7:00am

DCAS field trip to Pennyfield Lock, Saturday May 5. Report by Paul DeAnna

On Saturday, May 5, a capacity crowd met leader Paul DeAnna for the 9^th annual DC Audubon field trip at Pennyfield Lock on the historic C&O Canal. The old canal stretches for 184 miles from Georgetown in D.C. all the way to Cumberland, Maryland, and I know of no other park offering such lengthy, unbroken river access anywhere in the country. It’s truly an amazing resource for hikers, bikers, fishermen, canoeists (where the canal is rewatered, as here) and, of course, birders. Here one can step back to a day when life moved at a slower pace, and take a little time to commune with nature. Pennyfield Lock has its own history: President Grover Cleveland used to fish here, and during a later era, Roger Tory Peterson used to bird here often when he lived near Cabin John, Maryland back in the 1950’s. The spot also gets a mention in Louis Halle’s classic book, Spring in Washington.

Our day got off to a nice start with an Eastern Phoebe characteristically bobbing its tail while perched near the lock; she’s probably nesting right under the bridge across the canal. Behavioral clues like this are always pointed out in good field guides, and they can often make identification easier. A bit further on, we watched a tiny Ruby-throated Hummingbird perched in a thin, bare branch at the top of a tree. Small they may be, but they still stand out in these “lookout” positions, if one knows where to look. Soon after, as if to provide size contrast, our largest woodpecker, the Pileated, alighted in a snag just across the canal. The Pileated is so named for its red “pileus,” or “liberty cap” (to see another liberty cap in use, view Delacroix’s famous painting, “Liberty leading the people”).

About a quarter mile from the lock, as we neared the point where a small stream runs through a tunnel under the canal, the group spotted a blue bird singing on the other side, which we first thought to be an Indigo Bunting because of its very dark blue color. On closer inspection, though, and especially after hearing the song more clearly, it was correctly identified as a Blue Grosbeak. This is a good example of the importance of learning songs and calls that are less familiar. In fact, learning bird song is really one of the best ways to begin to take your birding skills to the next level.

Scarlet TanagerSlowly, very slowly, we continued westward up the towpath, finding a number of brilliant birds along the way, including perennial favorites like Baltimore Oriole, Scarlet Tanager, and Rose-breasted Grosbeak. Now that’s what I call “local color.” All but the grosbeak are likely to nest here. We also got to compare a number of Indigo Buntings to the Blue Grosbeak seen earlier, noting the complete lack of any brownish tinge to the wings in the bunting, as well as the smaller, sparrow-like bill. If you listen carefully, you will hear the Indigo Bunting repeat almost every note twice, with a finch-like twitter. It’s much different from the husky up and down warble of the Blue Grosbeak.

Green HeronStarting at milepost 20, there are two watered impoundments between canal and river, and these are always worth checking. We found a number of Green Herons, as well as Great Blue, and a female Hooded Merganser was also spotted. Wood Ducks, which nest in the boxes provided along the edge of these ponds, were seen only in flight on this day, however. A Yellow-billed Cuckoo was observed adjacent to the second pond, feeding on the many tent caterpillars. Eastern Bluebirds were in the neighborhood, as well. Prothonotary Warblers, also cavity nesters, sometimes take up residence in the vicinity, so be sure to watch for them should you return on your own. Although we missed that species, we did find a couple of Parula Warblers singing high in the trees. Early spring is the time to see them because once the trees leaf out in full, they easily disappear behind the smallest bit of green, and are identifiable only by their song: a buzzy trill that rises rapidly in pitch and then snaps off abruptly.

Singing Louisiana WaterthrushAnother of the wood warbler group gave us an excellent close view, though. It was a Louisiana Waterthrush, feeding slowly along the edges of a fallen branch in the canal. This bird seems to bob its entire body as it hunts for insects and sometimes takes tiny snails along the bank. It can be very difficult to distinguish from its nearly identical cousin, the Northern Waterthrush. In this case, also, knowing their distinctive songs is the easiest way to identify them.

At the scenic “Seneca Breaks” (milepost 21), we reached our turnaround point. This is opposite the western end of Watkins Island, and here the full width of the Potomac becomes apparent. Before we headed back, though, we added to our list the Spotted Sandpipers seen on rocks in the river, as well as a Bald Eagle spotted perched high in a tree on the Virginia shore. Our return was uneventful in terms of new species, but we did get a much better view of the Yellow-throated Vireo seen earlier. We searched in vain for the Acadian Flycatcher identified by call only on our way up. Try again for this species a bit later in the season, when warmer weather brings out more flying insects.

It was a little past noon when we reached our starting point at the lock parking area, by which time the birds were noticeably less active and hikers and bikers more so. Remember, should you return on your own, this area has become quite popular, and it’s best to arrive and finish early; alternatively, if you can manage it, come on a weekday. Consider also paying a visit to other nearby canal spots, such as Violette’s Lock (mile 22), and Seneca, also called Riley’s Lock (mile 23). Birding either one can be just as rewarding as Pennyfield. I want to thank all participants for their sharp-eyed contributions to the list which follows, and invite you to contact me should a species be inadvertently missing. Good birding!

Birders Enjoy Spring on the C&O Canal:  Photo by Peter Vankevich.

More photos from the trip are available in the image galleries.

List of species identified:

1. Double-crested Cormorant

2. Great Blue Heron

3. Green Heron

4. Black Vulture

5. Turkey Vulture

6. Canada Goose

7. Wood Duck

8. Mallard

9. Hooded Merganser

10. Bald Eagle

11. Spotted Sandpiper

12. Rock Pigeon

13. Mourning Dove

14. Yellow-billed Cuckoo

15. Ruby-throated Hummingbird

16. Belted Kingfisher

17. Red-bellied Woodpecker

18. Downy Woodpecker

19. Pileated Woodpecker

20. Wood Pewee

21. Acadian Flycatcher

22. Eastern Phoebe

23. Great Crested Flycatcher

24. Eastern Kingbird

25. Yellow-throated Vireo

26. Red-eyed Vireo

27. Blue Jay

28. American Crow

29. Tree Swallow

30. Carolina Chickadee

31. Tufted Titmouse

32. White-breasted Nuthatch

33. Carolina Wren

34. House Wren

35. Blue-gray Gnatcatcher

36. Eastern Bluebird

37. Wood Thrush

38. Catbird

39. European Starling

40. Northern Parula

41. Yellow-rumped Warbler

42. Louisiana Waterthrush

43. Common Yellowthroat

44. Scarlet Tanager

45. Song Sparrow

46. White-throated Sparrow

47. Northern Cardinal

48. Rose-breasted Grosbeak

49. Blue Grosbeak

50. Indigo Bunting

51. Red-winged Blackbird

52. Common Grackle

53. Brown-headed Cowbird

54. Orchard Oriole

55. Baltimore Oriole

56. Goldfinch