Range changes occur when a species moves into (expansion) or out of (contraction) an area. These changes may take place within a few years or over many years, and the changed distribution may continue indefinitely.

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The above maps demonstrate the range expansion of Mourning Dove that has taken place between 1950 and 1999, northward in the West and into the Great Lakes. This is based on data from the Christmas Bird Counts. More information about range expansion in North American doves can be seen at this address: http://www.birdsource.org/features/doves/index.html

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