Local or Migrant: Which Is Which?
When robins start moving, how do you know which ones are your "own" local robins and which are migrants just passing through?
You can usually tell by their appearance unless they have been banded or color-marked. Male robins from Newfoundland and Labrador are darker than other robins. They have almost black backs, brighter red underparts, more noticeable striping on the white throat, and a bolder eye-ring. People farther south in Canada and the U.S. may notice the difference when they spot one of these robins; then they'll know for sure that these are the northern race rather than their own breeding robins. Many magazine photos of winter robins show these brightly colored ones, which make a lovely contrast against snow-covered branches and orange berries.
If you keep your ears peeled, you may be able to hear the difference between local and migrant robins. Male robins that intend to remain in your area will sing their territorial song. Robins that are passing through will occasionally sing, but not as often (especially at dawn); they tend to remain fairly quiet.
National Science Education Standards