Biology rules. Tony Leukering summarized vagrancy in this pithy statement,
which, I think explains the basic biology involved.
"Such a long movement by an individual of a non-migratory species [or, I think,
any species] is . . . not just a matter of packing one's bags and heading out.
There are physiological processes that MUST take place in order to allow such
movements. The individual must alter its biochemistry and go through a period
of hyperphagy ("frantic consumption of food") in order to lay on the fat
required to fuel the trip. Without these processes, the bird is going nowhere."
Anyone who has watched bander Meredith McBurney blow on a warbler's furcula to
measure fat can make the connection. And this probably explains why some
migrants hang out in the same place for a week or 10 days, then disappear. They
stay in order to build up their fat reserves before they go to their summer
homes.
Hugh Kingery
Franktown, CO
PS -- Thanks also, as Tony says, to the Colorado Records Committee. Efficient
and thoughtful.
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