The Christmas Bird Count (CBC) is an annual survey sponsored by the National Audbon Society and conducted by over 40,000 volunteers at over 2000 sites throughout North America. Each count covers a circle 15 miles in diameter, each circle typically being split up into several or more areas, each of which is covered by a party of birders. Background information as well as a wealth of data can be found at the the official CBC site.
On Cape Cod, five counts are conducted each year. The oldest is the Cape Cod CBC, which started in 1930 and includes most or all of the towns of Eastham, Orleans, Chatham, Brewster, and Chatham. The Buzzards Bay CBC began in 1970 and in 1972 the count area was shifted eastward a bit to include more of Cape Cod; it includes most of Falmouth and Bourne, and the southwest corner of Sandwich. The Mid-Cape CBC has been conducted since 1981 and includes most of Dennis, all of Yarmouth, and most of Barnstable. The Stellwagen CBC was initiated in 1988 and included Stellwagen Bank (covered by boat, weather permitting) and most of Provincetown; in 2009 the count was changed to a boat only survey of the Stellwagen Marine Sanctuary, excluding the land-based portion in Provincetown. The newest count is the Truro CBC, which includes most of Wellfleet and all of Truro, and began in 1996.
Since 1984, the Cape Cod Bird Club has conducted an annual survey of waterfowl on Cape Cod ponds and lakes. The survey takes place on the first weekend in December and covers well over 300 water bodies. The number of waterfowl recorded has varied greatly from a low of 6782 individuals in 2005 to a high of 13,637 in 1998, and the number of species has ranged from 22 to 31. Visit the Waterfowl Survey page to download the annual summary reports (1995 - present) and a spreadsheet with the complete survey results.
From 1975 - 1979, a Breeding Bird Atlas sponsored by Mass Audubon was conducted throughout the state of Massachusetts. Results of this effort were published in 2003 and are available online through Mass Audubon's site or from this USGS site.
A second 5-year Atlas was begun in 2007 and concluded in 2011. Information about this latest Atlas is available from for the Mass Audubon site.
For over 40 years, the USGS has sponsored roadside Breeding Bird Surveys, in which observers follow a 24.5 mile route, stopping every half mile and recording every bird they see or hear for a three-minute period. These simple surveys, conducted throughout North America, provide an invaluable index on trends in breeding bird populations across the continent. The results of this massive effort, with extensive data analysis, are available online at the USGS site.
Three routes have been conducted on Cape Cod over this time frame, though the coverage has been sporadic. One route (E. Dennis, Route #47001) begins in E. Dennis and ends in Sandwich, the second (Wellfleet, #47004) starts in Truro and ends in Brewster, and the third (Cape Cod National Seashore, #47901) runs from Eastham north to Truro). Results of these local routes are available at the USGS site (click on the "Route level Analysis" button).
The Wing Island Bird Banding Station has been in operation since September 2000 under the direction of Master Bander Sue Finnegan. The station is sponsored by the Cape Cod Museum of Natural History in Brewster, MA and is situated on 80 acres abutting a sprawling salt marsh and 300 acres of conservation land.
Beech Forest Spring Migration Survey
Since 1980, Blair Nikula has been conducting standardized surveys of spring migrant songbirds in the Beech Forest in Provincetown. These surveys are conducted primarily during May and involve walking the same route early in the morning and recording all birds heard or seen. A spreadsheet (in pdf format) showing the annual results (expressed as the average number of birds/census) from 1982 - 2007 can be downloaded here. Results since 2008 have been entered into eBird.