Note:The analysis presented here is based on the data submitted as of November 2006. Since that time, we have received more data from several of the missing miles. For the most complete data, see the updated data sheet for 2006 [0].

The 8th annual C&O Canal Mid-winter Bird Survey [0] was completed on Saturday, January 21, 2006. This bird survey aims to determine and monitor the winter bird population along the C&O Canal National Historical Park [1]. The canal stretches 184.5 miles, from its eastern terminus in Georgetown to its western terminus in Cumberland, Maryland. Surveying the bird population along the canal has required a sustained effort by volunteers in at least four states and the District of Columbia.

Fifty-seven observers covered sectors along the length of the canal during the 2006 count. Observers are divided into teams, most of which cover a short, 2-4 mile sector. A few hardy participants cover much more than that. In contrast to the harsh weather from previous years, this year's count day was pleasantly mild, despite overcast skies and some intermittent rain. Unfortunately, due to miscommunication and the sudden resignation of the lead compiler, we only have reports from 118 miles, a low for the survey. Problems with gathering and processing data have also delayed publication far beyond when the data should have been published. For this, we apologize.

Data from the count is presented in spreadsheet form, as in past years. Miles are numbered according to the milepost at the beginning of each mile, so that the first mile is '0', the second mile is '1', and so on. Each mile is reported on a separate checklist and entered into the data sheet in a separate column. Here is the data sheet for 2006 [1]. It should open in any standard spreadsheet software. Totals for each species can be viewed in a table on the canal count index page [1].

The reduction in miles covered means that the numbers of individual species will need to be taken with a grain of salt, especially where they show moderate declines from previous years. However, we hope that by making the existing data publicly available, we might facilitate the study of individual miles or groups of miles. If you have a report from a mile not included in the data sheet, please send it to us [1] so that we can add it.

Results

Observers recorded 74 species of birds on the 2006 count. This represents a 13% decline from the average of the previous three years and is well below the high of 91 species in 2002. Likewise, the total number of individual birds fell to 12,718, about a 32% decline from the average of the past three years. When one excludes Canada Geese from consideration, bird numbers show a less severe reduction; observers counted 11,591, about a 10% decline from the average of the past three years.

These figures, however, need to be interpreted in light of the fact that fewer miles were covered than in previous counts. The average coverage of the past three years was 169 miles, so our mile coverage in 2006 fell by about 30%. In that light, the 13% decline in total species and total (non-goose) individuals does not look so bad. The closest analogy in terms of miles covered is 2001, when reports were received from only 129 miles. Figures from 2006 are roughly comparable to that year, even if we saw fewer species overall.

The sector with the greatest species diversity was Mile 20, where observers reported 40 species. It was followed closely by the 34 species reported in Mile 22. The highest number of individuals was the 739 reported in Mile 3. A little under half of those birds were Ring-billed Gulls.

The biggest story from this year's count is the sharp reduction in the numbers of Canada Geese counted by observers. The previous low for that species had been 3678 in 1999, the very first year of the survey.

In the past three years, the numbers of individuals reported were 9609 in 2003, 5933 in 2004, and 5679 in 2005. In 2006, the number was down to 1127. The reduction cannot be explained solely in terms of lower coverage, as the number per mile also fell. Whether this represents a real decline, a response to hunting pressure and control efforts [2], or simply a one-year aberration remains a question for future surveys.

Other species notes follow.

Waterbirds. A Red-necked Grebe in Mile 97 was a first for the count, bringing the total number of species for the survey to 112. Despite their down year, Canada Geese just beat Ring-billed Gulls to retain their title as the most numerous species reported. American Black Ducks are significantly down from previous years, with only 113 reported for 2006. American Coots continue to be notable by their absence; since a high of 417 in 2000, they have not broken double digits in any subsequent year.

Vultures. Seventy-eight Black Vultures were reported in 2006, a new high for this count. Turkey Vultures just missed matching their previous high in 2002.

Gulls. Ring-billed Gulls were a high for the count, with 1103. Their previous record was 1040 in 2002.

Woodpeckers. It was a lean year for Yellow-bellied Sapsuckers and Hairy Woodpeckers, with only 61 of the former and 58 of the latter. Downy Woodpeckers also seem to be underrepresented in this year's survey.

Passerines. Eastern Phoebes had their lowest year ever, with only 5 recorded, despite the mild temperatures. Carolina Chickadees had a strong year; 835 was their highest count since 2003. Six Red-breasted Nuthatches were the most individuals of that species since eight in 2000. American Robins set a new high with 1095 individuals. Cedar Waxwings had their second-best year, with 378. White-throated Sparrows and Dark-eyed Juncos were both significantly down from their previous highs. Observers recorded the most Common Grackles since 2002. Purple Finches hit their high for the count, with 19. House Sparrows had their second-best year, with 123.

Thanks to all who participated in the C&O Canal Mid-winter Bird Survey for 2006. This survey would not be possible without the enthusiastic work of many volunteers. Again, we apologize for the late publication of the data. If you know of any additional reports from miles not included in the data sheet, or if you know of any observers not listed below, please let me know [2].

An announcement regarding next year's count will be posted on the canal count index page [2] and local birding lists in the near future. To receive emailed announcements regarding the count, you can sign up for the mailing list here [2]. We look forward to counting with you again in January 2007!

List of Participants

Return to the canal count index page [2].