National Audubon Society Christmas Bird Counts at Mono Lake

Q: What is the Christmas Bird Count?
A: A coast-to-coast annual bird census. Volunteers count every bird and bird species over one calendar day--from midnight to midnight. Over 45,000 people from all 50 states, every Canadian province, the Caribbean, Central and South America and the Pacific Islands (all the areas where the breeding birds of North America spend their winters) participate in more than 1700 counts held during the two and a half week period.

Q: Why?
A: Bird are indicators of the overall health of our environment. Christmas Bird Count data over time in any given area can provide insight into the long-term health of bird populations and the environment.

Count Rules: Each bird count is a circle 15 miles in diameter -- approximately 177 square miles. Bird counters try to cover as much of the circle as possible with a 24-hour calendar day, counting each individual bird and species they see.

For full info on the CBC: http://birdsource.cornell.edu