Distribution of Cassin's Finch
Using Range Maps
Range maps should be used with the understanding that they provide only a general indication of typical distributions. Ranges are highly variable for many species and are very dynamic. Range maps are static and usually several years behind the birds. These are some of the complications that present themselves when developing range maps.
Report your sightings
In the Field
Range maps in field guides vary as much as actual bird distribution. Take two different field guides, select 20 images at random, and compare the range maps. You might be surprised by the differences in the ranges shown.
The Professor's favorite field guide for range maps is the Kenn Kaufman Guide to Birds of North America. Here are the Professor's picks for the best field guides.
Breeding Bird Census
Christmas Bird Count Data
Winter range of the Cassin's Finch, based on Christmas Bird Count data.
Map from the Patuxent Wildlife Research Center.
Gough, G.A., Sauer, J.R., Iliff, M. Patuxent Bird Identification Infocenter. 1998. Version 97.1. Patuxent Wildlife Research Center, Laurel, MD.
Visit the Audubon Christmas Bird Count web site to create your own range maps.
Additional Web Resources
The Avian Knowledge Network collects data from thousands of locations and multiple data sets.
The Birds of North America web site has excellent distribution information, annual membership required.
Visit the eBird web site to report sightings of the American Goldfinch and to view current and some historical information on a state-by-state basis. Information based on reports from birders in the field.
NatureServe provides information on birds and other wildlife.