December 5, 2008

RIVER WATCHER

THE HUMMINGBIRD WATCH

Rex Burress

Some people may think that saying "hummingbirds

in Oroville in the winter" is akin to saying

"Cows in Berkeley." But the Anna's Hummingbird

indeed spends the cold season around Oroville

river-town, flourishing on winter-blooming plants

and back-yard sweet-water feeders!

Most species migrate south where there are more

flowers and sunnier habitats. Some, like the

eastern Ruby-throated, cross the Gulf of Mexico

in one 500-mile flight! South America is

hummingbird heaven, and of the 340-worldwide

species, most are found there. They are endemic

to North and South America, although a rare

30-million-year-old fossil was found in Germany,

indicating greater distribution at one time.

Fossils are few because of the delicate bone

structure.

The Anna's in Oroville are fond of the

red-flowering iron-bark Eucalyptus along the

parkways path near the auditorium. This

Australian introduced tree blooms right through

December, and dozens of hummingbirds feed on the

dense lovely blossoms. Calypte anna and other

species are drawn to red, especially the red of

the California Fuschia along the river in

September through November.

The hummingbird is one of the most active of

birds, featuring a high metabolism that needs

large quantities of food-energy to function. They

sip their way through enough nectar and small

insects daily to equal their body weight, which

isn't much, usually less than an ounce, and the

smallest bird in the world, the Bee Hummingbird

of South America weighs 0.06 ounces. They choose

high quality nectar, too, ignoring flowers

producing less than 15% sugar and preferring at

least 25%.

The rapid wing-beat takes most of the energy,

beating at about 50 times per second, and during

courtship high-speed displays, as much as 200

p.s, while the heart may beat 1260 times per

minute. Highly maneuverable, it is the only bird

able to go in all directions, even backwards, the

wings "sculling" in a figure "eight" to

accomplish the feat. It was not until the 1950's

when, with high speed photography, the wingbeats

could be counted.

These requirements would tend to minimize their

winter-time activity, and their key to existence

along the river in freezing weather, is to go

into a torpor-sleep where the heart may drop to

50 beats per minute. They do become dependent on

bird lover's feeders to supplement nectar during

cold spells, so keep it up if you start. You can

do a good turn, plus seeing the intense

iridescent beauty of the bird closeup. Mix one

part sugar and two parts water, and keep the

feeder clean.

It is marvelous the way pollinating plants have

evolved a way to attract hummingbirds to help

spread pollen and aid plant reproduction. It is

equally fascinating that nature has a bird

designed with special beak and tongue to probe

flowers, and wings to hover in tight places.

John Muir spoke of his favorite bird being the

"Hummingbird of the Sierras," but his choice was

not the nectar-eater, but rather the "Water

Ouzel," or American Dipper that flutters in rapid

streams to feed on aquatic life. The "hum" is the

Dipper's habit of singing constantly, even in

winter as it emerges from icy water! A wide range

of bird styles means diversity in nature.

"Darting, hovering, helicopter fueling at a flower

Tell me how your engine heart generates such power."

-Joel Peters