Cape Cod Waterfowl

Click for spreadsheet file

Select one or more:
Years: Species: Ponds:


During the first weekend of November of 1983, Blair Nikula and members of the Cape Cod Bird Club initiated a census of the lakes and ponds on Cape Cod. Participants were instructed to identify and count all the water-fowl (loons, grebes, geese, ducks, and coot) present on each pond. Covering 202 ponds, participants tallied 3,957 individuals of 22 species of waterfowl.

The census continued the following year but was moved to the first weekend in December. Many ducks and geese do not arrive on Cape Cod until inland bodies of water freeze and the later date would more closely coincide with peak water-fowl numbers locally. Covering 225 ponds, 25 species of water-fowl were counted with 9,097 individuals being recorded. This year, and in those following, detailed counts of each species on each pond were recorded. These provide the data presented on this website.

Now in its 33rd year, the Cape Cod Waterfowl Census is an excellent example of citizen science in which birders, regardless of their expertise, can gather useful data and make a meaningful contribution to our knowledge of the Massachusetts avifauna. Waterfowl are relatively conspicuous, generally easy to identify, and thus readily censused with only a modest effort. In 2015, the survey covered 267 ponds, 25 species of water-fowl and 7,183 individuals.

If you would like to participate:
Please contact Charlie Martin at


A trend line is included for each count. This is a straight line (linear regression) fit to the counts for each year. Two values define the trend; the trend value for the first year displayed, e.g., 1984, and the increase or decrease in the count for each subsequent year.

The trend value for a year can be computed as follows:
The trend value for the first year plus the "Per Year" value times the number years after the first year.
e.g., if the first year displayed is 1984, then the trend value for a year is
the "1984" trend value + (year - 1984) * "Per Year" value.

Spreadsheet File:

The spreadsheet style display includes a link at the bottom of the webpage to a spreadsheet file containing the same data as that displayed. This is intended to facilitate further use and analysis of the data.

Selecting the Years, Species and Ponds:

Click the "Select" button at the upper right to select the years, species and ponds to be included in the spreadsheet and graphs. Click "Display Table" to view the results in a spreadsheet style or click "Display Graph" to view a graph of the counts by year along with a trend line for each species.

Click the name of the species, or a total, in the spreadsheet display to view a graph of the counts for that species

The Website:

Copyright© 2015 Blair Nikula All rights reserved
Copyright© 2015 Cape Cod Bird Club All rights reserved
Copyright© 2015 Atlantic Database Systems, Inc. All rights reserved