Date: 2/18/18 11:16 pm
From: Nathaniel Wander <nw105...>
Subject: [obol] American Robin migration
I too noticed robins on my NW Portland patch this afternoon for the first time since fall.
I'm not sure exactly how this works out in terms of who ends up breeding where, but I believe that American Robins are leap-frog migrators.  That is to say, northernmost populations over-leap middle latitude ones in to travel to their wintering grounds and middle-latitude breeders similarly over-leap the most southerly breeders.
Nathaniel WanderPortland, OR
Max Planck is supposed to have said: A new scientific truth does not triumph by convincing its opponents and        making them see the light, but rather because its opponents eventually die        and a new generation grows up that is familiar with it.Andreas Wagner observed of Planck's remark: Science, like nature, advances one funeral at a time.  (Arrival of the Fittest, p.197)
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