Latest update: 5 January 2010
TRENDS IN POPULATIONS OF BREEDING BIRDS
IN CHATHAM COUNTY, NC, 2000-2009

These graphs show the total number of individuals of each species recorded on all routes in one county in each year.

Each species has a four-letter code (usually the first two letters of its first name and the first two letters of the its second name (for instance, EABL for Eastern Bluebird).

Some species show trends (either upward or downward) in their numbers over the period of the surveys.   A straight line on a graph indicates a trend that is statistically significant (not likely to be an erroneous conclusion) or almost statistically significant.

** A double asterisk in the upper right corner of a graph indicates a highly significant trend (with a probability of error less than 1%).

* A single asterisk in the upper right corner indicates a significant trend (with a probability of error less than 5% but greater than 1%).

A line but no asterisk indicates a possible trend (with a probability of error less than 10% but greater than 5%).

For more information about the N. C. MBBS, see the
MBBS homepage

For a list of the species (with four-letter codes), see
MBBS birds

Please send suggestions to Haven Wiley!

R. Haven Wiley and NCMBBS volunteers (2010).
http://www.unc.edu/~rhwiley/mbbs/trends

Great Blue Heron to Chimney Swift

Red-bellied Woodpecker to White-eyed Vireo

Red-eyed Vireo to Brown-headed Nuthatch

Gray Catbird to Summer Tanager

Yellow-throated Warbler to Eastern Towhee

Field Sparrow to House Finch

House Sparrow and all species combined