A north wind ripples through green leaves of a great sprawling wisteria. Two rosy finches battle upwind, climbing to reach a power line. They land in tandem and appear to gaze off into the distance.
Why do birds sitting on a power line all face the same direction?
Birds fly and land into the wind for maximum lift and control of flight. All birds land into the wind, explains Bobby Harrison of Oakwood College in Huntsville, Alabama. These finches do likewise and, therefore, land facing the same direction -- into the wind.
The wind shifts direction, as it often does in springtime New Mexico, and the birds move with the wind, still heading into the wind and consequently still facing the same direction on the power line.
Now the wind dies. The becalmed birds begin to preen and hop about as the mood strikes and face different directions.
A few species, however, like the golden crown sparrow of California, still face the same direction. They do this even though no wind co-ordinates their choice, to keep relationships peaceful.
There you have it - when it is windy, birds face into the wind. Otherwise most species face randomly selected directions.
Many knowledgeable readers answered this question getting it right -- 77 per cent of the time.
- Birds sit on power lines, trees, roofs, the ground or anything at all, facing the direction they were flying when they landed and the direction they will need to go when they take off again, that is, into the wind. - Bill, Vevey, Switzerland
- Birds sitting on a power line, or even a cloths line, all face in the same direction because they are all facing into the wind. - Tom, Jamesport, New York, USA
- They don't! - Chris, California, USA
- Photographing wild birds by Bobby Harrison, All about birds, Cornell Lab of Ornithology,
- Golden-crowned Sparrows, Wild Birds Unlimited
(Answered Aug 9, 2010)
Editor's Note: Unfortunately, this will be April Holladay's last column on globetechnology.com for the time being. April is fighting health issues that she says makes meeting her own high standards of researching and writinging WonderQuest a difficult challenge. April will continue to write the occasional piece for her website and will be welcomed back to globetechnology as soon as she feels she is able. Until then, we'll miss her insightful and entertaining column. -- Michael Snider