The Christmas Bird Count

Go to www.audubon.org/bird/cbc/. First, look at the general description of the most recent count in the pdf file provided by the Audubon Society.

1. How many people participated in the most recent bird count and how many species did they see?

2. Go back to the Audubon main page, then down to "What we’re learning." Choose "Population Trends in Evening Grosbeak." Look at the graph of bird counts from 1960 to 1999. How would you analyze this graph? Why do you suppose the data fluctuate so much? What is an irruptive species? Now look at the map of distribution in 1998. Where is this species most abundant?

3. Now look at "Grackle Expansion." Follow the spread of grackle populations on the active map for the decades between 1900 and 2000. Is it possible that there may simply be more counts occurring in grackle territory? Compare the map of Christmas Bird Counts at the bottom of this page. Where do most counts occur?

4. Find the location of a survey circle in your area. Click on the "Local Audubon" site at the top of the main page. Then choose your state (or country if outside the United States) to find information about a chapter near you. The Fish and Wildlife Service of the USGS also has a useful web page. Go to www.mbr-pwrc.usgs.gov/cbc/cbcnew.html. Click on "Winter Season Abundance Estimates" or "Abundance and Change on CBC Circles" to find an interactive map that will identify a count circle near you. Analyze data by population variations by individual species for particular sites.