Wind Tunnel Experiments Reveal Dynamics of Hummingbird Flight
Scientists have found out that hummingbirds and insects don’t hover in the same way. Insects support 50% of their weight on both up and down strokes, but hummingbirds support 75% on the downstroke and 25% on the upstroke. This was published in Nature this week,1 and summarized on Science Daily.
The latter article reminds us why hummingbirds attract our interest:
“You would be hard-pressed to find someone who isn’t amazed by hummingbirds,” said H. Ross Hawkins, founder and executive director of The Hummingbird Society. “Perhaps it’s their iridescent coloration and miniature size, or their ability to drop their heart rate from 500 beats per minute during the day to 40 beats per minute at night.” (Emphasis added in all quotes.)
Another bird story making the rounds this week was published in Science.2,3 Apparently, chickadees have a sophisticated signalling system in their chirps. They can alert the flock to a size and type of predator nearby with a kind of chirping language; the number of “dee” syllables at the end of the call is code for the kind of threat. See EurekAlert, National Geographic News, Science Now and People’s Daily Online.
1Warrick, Tobalske and Powers, “Aerodynamics of the hovering hummingbird,” Nature 435, 1094-1097 (23 June 2005) | doi: 10.1038/nature03647.
2Templeton et al., “Allometry of Alarm Calls: Black-Capped Chickadees Encode Information About Predator Size,” Science, Vol 308, Issue 5730, 1934-1937, 24 June 2005, [DOI: 10.1126/science.1108841].
3Greg Miller, “Bird Alarm Calls Size Up Predators,” Science, Vol 308, Issue 5730, 1853-1855, 24 June 2005, [DOI: 10.1126/science.308.5730.1853a].
There are few classes of animals more varied, colorful, intelligent, talented and interesting than birds. Makes you wonder what they think when they take up people-watching. Perhaps it’s best we don’t know what that chickadee is telling its friends when we walk by. When a Darwinist says, like in the Miller article quoting James Hare, “The work … shows us that even very common species that we may take for granted have evolved to have very elaborate and exacting systems of communication,” they might be chirping, check a duh, duh, duh.