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| American Robin Photo by Larry Halverson |
Length of daylight is one of the main bird migration influences. However ornithologist, Rick Howie says "the northward movement of Robins often matches a line across North America where the average temperature is 2 degrees centigrade. As temperatures warm and this "isotherm" moves northward, the majority of robins follow it."
The Robins in the Columbia Valley had to be surprised this morning (April 7th) by the 6 inches of new snow.
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