Each year in the summer and winter, volunteer birders around the state conduct a census of birds in designated territories. The Summer Bird Count (SBC) and Christmas Bird Count (CBC) are citizen science programs that have been run for over three decades and aim to count birds within several 15-mile diameter circles scattered across the state to help track population changes.

COA publishes the results of these surveys in its ornithological journal The Connecticut Warbler. Due to space constraints, some of the data is not included in the printed journal but can be accessed here. Below are links to the data on Google Sheets or as PDFs.