C&O Canal 2001 Report

Overview (adapted from DC Audubon newsletter, June 2001)

Results of the Third Annual Chesapeake and Ohio Canal National Historical Park Mid-Winter Bird Survey are now in! All reports have been received, reviewed, and tabulated. The C&O Survey is DC Audubon’s most ambitious birding activity, intended to give a detailed picture of winter birdlife along the entire 184.5 miles of the Park, from Georgetown to Cumberland.

We scheduled the survey for Sunday, January 21, avoiding Inauguration Day. Again this year, the weather was uncooperative. In 1999 we had rain on the morning of the survey; in 2000 the threat of a snowstorm, and in 2001 we had an actual snowstorm of greater duration and accumulation than had been forecast, although the skies cleared by afternoon of count day. All 185 mile-segments had been definitely assigned, but the snow made it impossible or imprudent for some participants to reach the Canal towpath. The actual coverage was 129 miles this year, compared to 138 in 1999, and 142 in 2000. (The 129-mile total does not include three miles counted in a make-up outing the following Friday.) We are confident of achieving 100% coverage in 2002, based on the enthusiastic comments of the 70 birders who participated in 2001, and the obviously sincere regrets of those who had conflicts or were snowed in. As in previous years, our Allegany County coverage is owed to the organizing efforts of Ray Kiddy of Cumberland, and we look forward to support from the Potomac Valley Audubon chapter, based in Shepherdstown WV, for the Washington County portion of the survey.

The weather probably contributed to the low landbird count, whether because birders got late starts, or because the birds genuinely made themselves scarce. Individuals other than geese and ducks numbered about 7770, compared with 11081 in 2000 and 7928 in 1999. Canada Goose unsurprisingly was the most abundant species at 5149 (some double counting of flocks is probable, but impossible to correct for) followed by 1837 Ring-Necked Ducks. Our species total was 80, against 89 in both previous years. The species total excludes Cooper’s Hawk, American Kestrel, and Brown-Headed Cowbird. The last three species were seen by a birder stationed on the old Western Maryland railroad bridge at mile 183, unfortunately not within the bounds for the survey, as the bridge is barely outside the Park limits. Species first recorded in 2001 were Northern Shoveler, Northern Pintail, Gray Catbird, the archivable but uncountable Brown-Headed Cowbird, and - the most exciting addition - an adult and an immature Golden Eagle. Blue Goose was a repeat, almost certainly the same individual seen in 2000.

After three years, the C&O Mid-Winter Survey has become a welcome event for regional birders, and is starting to provide interesting year-to-year and mile-to-mile comparative distributional information. Excel® spreadsheets with the 1999, 2000, and 2001 complete tallies can be emailed. Send your request to mikemilton@attglobal.net.

Data Presentation

The spreadsheet for the 2001 count is a 100kb Excel® 5 file, displayable with Windows® 95 and newer platforms. It will print legibly on six 8.5”x14” pages, numbered left to right (ascending mile-segments of the Canal) and then top to bottom (non-passeriforms and passeriforms). Each page displays a species column, a mile-segment row, and a row with initials of the reporting observer. Column totals are the number of species and numbers of individual birds in a mile-segment. Row totals are, for each species, the total number counted and number of mile-segments in which any were observed. Pages 3 and 6 display comparative aggregate data from 1999 and 2000. Comments on certain cells are displayed on the print-out. When the file is saved, these comments may default to a red indicator dot, or to locations where they mask data entries, and will have to be moved. The comments can be reformatted to display and print on a seventh page. Spreadsheets for 2000 and 1999 are in a similar format, also Excel® 5. If you want hard copies mailed, just let me know.

The mile-segments are numbered starting with “0”, and thus correspond to the milepost marking the downstream terminus of that sector. This numbering seems to be the least confusing way to report segments covered, and to correlate with the maps and descriptions in Hahn’s Towpath Guide. The order of species is the same as on the checklist provided to participants, and has not caused complaints.

Corrections and comments will be greatly appreciated.

Coverage and Participation

As mentioned above, the survey has gained acceptance, notwithstanding the decrease in miles actually counted in 2001. If the weather cooperates in 2002 – this is after all a mid-winter count - the goal of 183 mile-segments should be achieved on the ground, as it was on paper this year. Perhaps NPS will reconstruct the towpath at miles 86-87, or an intrepid kayaker will bird that stretch, for literal 100% coverage. Vankevich’s vision vindicated!

Besides the snow, our January 21 date coincided with the Frederick County winter count, which we anticipated, and with the Prince George’s County winter count, which we did not anticipate. It was a week after the Allegany County winter count, where co-incidence would have been a plus. As always in the case of conflict, birders should honor their commitments and give priority to the activities of their own organizations.

Participants enjoyed the count, low numbers and predictable species notwithstanding. All are aware that negative or routine results contribute, over time, to an interesting and useful data collection for this IBA.

The spreadsheet displays the three-mile count conducted on Jan. 26, and the additional count of mile-segment 182 conducted from just outside the Park boundary. The observations are omitted from row and column totals, as the additional coverage, although welcome, is outside the defining conditions of the survey. The “view from the bridge” in mile-segment 182 reported 19 species, not one of which was among the 12 species reported from the towpath.

As bad-weather strategies for 2002 and future years, we may try better last-minute communications for redeployment, and more one and two mile assignments.

Species Comments

The 1999-2001 numbers are generally in line with Hatfield et al., Distribution and Abundance of Birds Wintering in Maryland, 1988-1993, Maryland Birdlife 50:1-4 (1994).

Waterfowl: Appalling goose numbers. As noted, waterfowl results are subject to major vagaries of double-counting and undercounting, as a flock may or may not be in view from a given river access point, and no counting protocols are in force, beyond general encouragement to check out the river.

The two Hooded Mergansers in mile-segment 64 are inferred from the four reported in 65. The observer saw three distant pairs, but reserved his ID because of apparent size discrepancy compared with Ring-billed Gulls and Common Mergansers.

Raptors: The adult Golden Eagle in 143 was well described. An immature was also seen at 182, from the RR bridge just outside of the count area.

Galliforms: Grouse in 1999; Turkey in 2000; both in 2001.

Woodpeckers: What other birds with numbers like 988 in 2001, and 1477 in 2000, are actually ticked off one-by-one? Our totals are still less than a usual Seneca Christmas Count. No Red-Headed yet.

The 211 Yellow-Bellied Sapsuckers in 2000 certainly represented a real increase in numbers, for that winter. The 2001 count of this migrant reverted to 54, more in line with expected ratios to other woodpeckers. Downy Woodpecker, recorded from 102 sectors, yielded to American Crow (105) as the most ubiquitous species.

Phoebe: The three-year total of 55 breaks down: 6 in the lower half of the Canal, below mile 93; 49 in the upper half. The pattern is consistent with Hatfield et. al., who show some concentration in the area of Hancock. Why such upstream distribution of this semi-hardy species?

Chickadees: The maps in Hatfield et al. show overlap of Black-Capped and Carolina, and mention “difficulty in distinguishing hybrids”, approximately between Sharpsburg and Little Orleans, i.e. about mile 70 to 140. This does not imply that the distribution is symmetric over that range. The most careful observations from our survey were Dave Smith’s in 2000 in mile-segments 122-125. He found mostly intermediates with more Carolina-like characteristics, and some distinct Black-capped. The 2002 (e)mailings to participants could well include a discussion of field characters, with criteria for when to record Carolina, or Black-Capped, or “sp”. Peter Vankevich and I have emended some “sp.” reports to Carolina, and some Black-Capped to “sp.”, where no details were offered.

Kinglets: Low numbers in 2000 (20 Golden-Crowned, 19 Ruby-Crowned) must have been real, whether or not significant. The 2001 count was 164 Golden, 64 Ruby.

Bluebird: From count-afternoon reports, it seemed everyone was finding bluebirds. Indeed, the 52 mile-sectors in which they were found was one more than in 2000, but the count was lower, in line with passerine numbers generally.

Conclusion: Thanks again to all participants. Discussion topic: should we build on the skill and enthusiasm of participants, plus the discrete segmented character of the count area, and move this survey in the direction of a true bird census - i.e. more standardized observation protocols?

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