Christmas Bird Counts

It's that time of year again. Shoppers crowd the malls, radio stations begin playing nonstop Christmas music, and kids count down the days until winter break. But for a few dedicated Audubon volunteers, the holiday season means getting up early and counting as many birds as possible for the annual Christmas Bird count. Last year 59,813 "citizen scientists" participated in the count, and counted a total of 65,596,663 birds.

One of the neatest features of the count is that the data collected is accessible through the CBC website. And it's not only raw data. Tools are provided so that you can map and graph species over time and location, making it easier to see trends. For example if you search for data from 1960 to the present on the American Kestrel, Falco sparverius, in New York you will see a steep decline over the last 30 years. There are a few theories on this decline, but as usually, habitat loss seems the likely culprit.

One of the often asked questions when looking at this data is whether climate change is causing or will cause a "northward" shift in species ranges over time. While it seems like a logical conclusion that species would shift to stay in their preferred habitat/temperature range, there are many other factors at work. Species that are specialized to live in unique or rare ecosystems may not have anywhere to go should climate change alter their habitat significantly. An analysis of Christmas bird count data found that in the past 40 years, a significant northward shift was seen in 68.2% of the bird species counted. [1] In New York State, breeding bird survey data has shown inconsistent results for a "northward shift". Some species did appear to shift their ranges north, while others shifted south. [2]

2009 marks the 110^th year of the Christmas bird count. Volunteers are assigned specific areas within geographical "count circles". There are circles all over the country, as well as circles in Canada, South America, and even Antarctica. Beginning birders needn't worry, as they are often paired with veterans in the field. Volunteers may also count birds that visit their feeders from the comfort of their homes. The count this year runs until January 5^th, if you are interested, contact your local Audubon society, or check out the official Audubon CBC page at: http://www.audubon.org/Bird/cbc/

[1] Niven, Butcher, and Bancroft. "Christmas Bird Counts and Climate Change: Northward Shifts in Early Winter Abundance" American Birds 63 (2008-2009): 10-15.

[2] McGowan, Kevin and Kimberly Corwin. The Second Atlas of Breeding Birds in New York State. New York: Cornell University Press, 2008.