I don’t have any pictures, but I can’t get the vision out of
my mind—a solitary bluebird huddled in the snow, head tucked into breast, feathers
fluffed, shivering. I thought I was watching adaptation, but I later realized I
was probably witnessing the process of dying. Birds do use all of the mechanisms I saw in
order to maintain and raise body temperature, but shivering is only a temporary
solution, taking an inordinate amount of energy. This unsheltered bluebird
had few remaining resources as the temperatures dropped that night.
The next day, after the final night of the storm, I found
two dead birds, and my friends reported others. Initially, I thought the cold
caused the mortality, but slowly I realized that these birds died primarily of starvation.
Because the insects they eat became inactive, the birds lacked the energy
they needed to survive.
My favorite Website about birds, that I'm always citing, reports that even hummingbirds can survive freezing temperatures as long as
there is food available. Spring may appear to be a season of abundance, but especially
in a climate like Colorado’s, where drastic fluctuations in weather occur, it
remains important to leave out birdfeeders while energy requirements are high
and food can be scarce.