Tuesday, July 13, 2010

American Robin

The American Robin is the most abundant of the North American thrushes.  Robins are so numerous that many folks don't appreciate their beauty.  I banded this male robin (you can tell it is male because of its dark head--females have much grayer heads) on 6 April 2009 and recaptured it on 12 July 2010. Male robins are monogamous during the breeding season, but usually take different mates in subsequent years.
I am fascinated by robin subspecies.  Turdus migratorius migratorius, found across much of North America, is the most common robin and is the one found in Minnesota.  T. m. propinquus is larger and paler than our birds and lacks the large white spots on the outer tail feathers. This race is found in the western US from British Columbia and Montana, south into Mexico and the Great Plains.  Two subspecies of interest to Minnesotans are T. m. caurinus of the rain forests of western Washington north to southern Alaska and T. m. nigrideus of the damp coniferous forests of eastern Canada.  Both of these races are darker-backed than our birds and both might be expected to appear in Minnesota in the winter.  In the northland, many non-birders are surprised when they see robins in the winter.  But robins are not uncommon during the winter and I have noticed that they are usually much darker-backed than are our breeding birds.  For both of these races, spending the winter in Minnesota counts as a southern vacation!  Nevertheless, be warned, I am aware of no verified records of either subspecies from the state. (Three additional robin races exist, one the the southeast US and the other two in Mexico.)

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