| What
Makes Rufous Hummingbirds So Tough?
It seems to be a normal year for timing of the migrations. So why
do rufous hummers move north so much sooner than rubythroats
do?
First,
let's explore what's different about Rufous hummingbird bodies.
- Rufous
hummingbirds are naturally cold hardy. They typically
overwinter in cooler areas than rubyhroats do. They often hatch
in cold mountainous areas and spend nights where the temperatures
are often near freezing. Ruby-throated hummers, which overwinter
farther south in warmer climates, are not well adapted to cold
temperatures.
- Both
species can enter a state of "torpor" in cold weather,
but rufous hummers do it more regularly. Their body temperature
lowers, slowing down their breathing and heart rates. In this
way, they conserve energy, which fuels migration.
But
that's only part of the story! Read on.
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