Naturalist hummingbirds

Nature's miniature teacher of toughness

We do not understand much about virtue, as Socrates
often observed. But one thing we know for sure is that
size has nothing to do with toughness.
Take the ruby-throated hummingbird, for example,
which could be hovering by your flowers like a
fine-tuned helicopter right now. It's about 3½ inches
long. It weighs about a 10th of an ounce. Its wings span
barely 4 inches. Its eggs are the size of peas. It eats by
poking its beak into blossoms and licking out sweet
nectar a drop at a time.
A drop at a time - its tiny grooved tongue flicks 12
times a second. While it hovers, its wings beat 80 times
a second. Its heart - an indicator of its metabolism,
which is the second-highest among warm-blooded
vertebrates (only shrews are more wired) - beats about
600 times a minute, and can double when the bird is
really exerting itself. A hummingbird takes about 250
breaths a minute. (Humans take about 12.) It has to eat
about every 10 minutes to survive in good health.
These numbers have the sound of precision biodelicacy.
Large dragonflies have been known to eat
hummingbirds. So have spiders, quick-witted cats, and
the odd kestrel streaking out of the sky toward the
flowers.
But these are unusual catches - in fact hummingbirds
have few persistent enemies, and this is due at least in
part to their nimbleness (hummingbirds are the only
birds that can fly backwards) and their alertness. They're
fiercely territorial, and mark off careful boundaries in the
trees which they defend like warriors.
But also, they are just physically tough. Hummingbirds
can fly up to 50 mph (barn swallows, the reddish-bellied
air acrobats, fly about 20 mph), and during spring
courtship rituals the males swing and dive in great showy
pendulums, beating their wings up to 200 times a
second.
Most remarkable, and instructive, is the annual
migration.
The ruby-throats are the only hummingbirds that nest
east of the Rocky Mountains. They arrive in Maine

around the beginning of May (the males get here first,
the females a week or two later), and set up camp for
the summer. In early fall they start stuffing themselves,
partly with the nectar of the remaining wildflowers,
partly with insects, and sometimes with tree sap from
holes drilled by yellow-bellied sapsuckers. For what is
about to happen is one of nature's amazing feats of
endurance: The tiny hummingbirds, departing Maine at
the end of September with stored-up energy, fly not
just south, but on across the Gulf of Mexico, covering
up to 620 miles nonstop.
The resilient ones make it to the winter homes in
Central America. The average ruby-throat may
accomplish this feat for four or five years. Some
durable hummingbird elders have lived to be 12.
I like our two cats, who skillfully keep mice from
infesting the walls and squirrels from chewing up the
logs of the house. But despite their 8-pound heft,
they're fat, lazy, mollycoddled Romans with an easy
morning's ride compared to the one-tenth-ounce
hummingbirds, who maneuver like Blackhawk
helicopter pilots around the dangers of the woods all
summer and then fly the emptiness of Gulf space to
Mexico. Now, that's tough.

© Dana Wilde 2007
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