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Kinglets and winter die-off



The ornithological literature seems weak when categorizing how birds
deal with severe weather. Some species are adapted to move with cold (or
warm) weather, but other cannot.

Birds that CAN move to escape severe weather tend to be those that
migrate during the day. Birds such as waterfowl, raptors, cardueline
finches, swallows, and seabirds fit that bill.

Birds that normally migrate at night, especially songbirds, do not
normally do this. They are adapted to migrate only in spring and fall,
by building up enough fat and having the proper hormonal "programming"
to migrate. Kinglets definitely fall into the latter category, as do
wrens, and many other songbirds. I feel confident to say that kinglets
simply do not, or better said cannot, make north to south migratory
movements during midwinter to escape bad weather. At the close of the
day, they gather into small groups perhaps (as was reported here about a
month ago), on limbs (in considerable cover), and may go into torpor (as
do hummingbirds). Hopefully, they survive the night.

One explanation for the kinglets in the western part of NC may be that
the weather was more normal there than in the eastern Piedmont. We
normally get 6" of snow a year, and we had a 20" snow, plus several
small ones, plus sleet and freezing rain. We DID lose a lot of kinglets
in the eastern Piedmont!

With this warm weather, it is possible that we are starting to see some
early northbound migration of kinglets that wintered farther south where
icy weather was not severe. Certainly, we should see an increase in
kinglets, at least for Rubies, in March and April as those that wintered
closer to the Gulf of Mexico are moving northward.

Harry LeGrand
--
Harry E. LeGrand, Jr.
N.C. Natural Heritage Program
Division of Parks and Recreation
1615 MSC
Raleigh, NC 27699-1615

Office: (919) 715-8687
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