today
9 a.m. Doris Niles Humboldt County Science Fair Humboldt State University
read >10 a.m. Annual Juggling Festival Humboldt State University
read >10:30 a.m. Green Jobs Fair College of the Redwoods Downtown Site
read >11 a.m. Baby Read and Grow Program Humboldt County Library
read >1 p.m. Apple Solutions for Small Business See Event Description
read >4 p.m. Young Parent Support Group College of the Redwoods Kinship Site
read >6 p.m. The Tumbleweeds (cowboy songs) Chapala Cafe
read >6 p.m. Bon Swing Libation
read >6 p.m. Annual Pisces Party See Event Description
read >6 p.m. Annual Pisces Party See Event Description
read >7 p.m. The Big Lebowski Arcata Theater Lounge
read >7 p.m. DJ Ray Boiler Room
read >7:30 p.m. Arianna String Quartet Calvary Lutheran Church
read >7:30 p.m. A Midsummer Night's Dream Arcata High School
read >8 p.m. Eureka Symphony Concert Arkley Center for the Performing Arts
read >8 p.m. Humboldt Folkdancers Arcata Presbyterian Church
read >8 p.m. On the Wings of a Dove Carlo Theater (Dell'Arte)
read >8 p.m. Antigone College of the Redwoods
read >8 p.m. So Hum Tales Mateel Community Center
read >8 p.m. Gentle Thunder Arcata Playhouse
read >8:30 p.m. The Last Minute Men (international) Cafe Mokka
read >9 p.m. Taxi (rock & roll) Bear River Casino
read >9 p.m. Vintage Soul (R&B) Cher-Ae-Heights Casino
read >9 p.m. Bump Foundation Pearl Lounge
read >9 p.m. The Brothers Comatose (folk) Six Rivers Brewery
read >9 p.m. The Malone (rock Red Fox Tavern
read >10 p.m. Music by DJ Sidelines
read >10 p.m. DJ Ninja Retro Dance Party Aunty Mo's Lounge
read >previous columns
March 6, 2008
The Ins and Outs of Tides
The Moon's gravity decreases with distance, so it pulls unequally ...
read >Feb. 21, 2008
More Power to You
PG&E is planning an upgrade of its aging Humboldt Bay ...
read >Photos
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NASA wake vortex study at Wallops Islands NASA Langley Research Center, May, 1990
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Diagram showing tip vortex, by Don Garlick.
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Diagram showing tip vorteces, by Don Garlick
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Diagram of tip separation to wing span of pink footed geese, by Don Garlick
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Graph of drag % relative to solo flight, by Don Garlick.
In Formation
By Don Garlick
The V-formations of honking Aleutian Cackling Geese that decorate our skies pose the question as to whether they fly in formation for social cohesion or to conserve energy. The reason military jets fly in V-formation is not to conserve energy, but to permit trailing pilots to remain in visual contact with the leading pilot. Fortunately, there are methods by which the question of energy conservation can be investigated. If trailing birds benefit from air currents produced by leading birds, then their relative positions should optimize those effects.
One might expect that a bird following very closely, with beak on tail, would experience less drag. Cyclists employ that "drafting" technique on the race track. However, air immediately behind a leading bird is sinking, so drafting is not a good tactic in flight.
Theoretical calculations indicate that a bird in a large formation could reduce "induced air drag" by 60 percent by riding the rising half of the wing-tip vortex produced by the bird ahead. The optimum effect occurs when wing tip directly follows wing tip with zero lateral spacing. Examination of vertically-taken photos of pink-footed geese confirm that those geese fly close to that optimal geometry.
The telemetered heart rate of a pelican has been found to be faster while flying solo than in formation (Nature, Oct. 18, 2001). This further confirms the energy-saving hypothesis. And a heavy goose flying non-stop from Humboldt to Alaska needs to be as energy-efficient as possible. That is why our sky is festooned with geese in formation.
Thirty years ago there existed fewer than 800 Aleutian Geese. Thanks to the removal of introduced foxes from critical nesting islands, their population now exceeds 100,000. That's too many, according to local dairymen who see their pastures flying away.

















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