dmunroe@copper.WR.TEK.COM (David Munroe) (12/13/90)
I apologize if everyone here knows the answer to this, but I don't know much about birds. Now that rec.autos is in the middle of a flame war, I've got a chance to post this. :-) The setting: Portland Oregon, early October, about 7pm, in a large weeded field (several acres) near a suburban shopping center. I noticed about 50 to 75 sparrowlike birds, probably larger and darker, clustered together and flying in large clockwise circles about 75 feet above the ground. Sometimes a few birds would break away, but they'd eventually come back. Sometimes several different groups of circling birds would join into one large group. What puzzled me is that they kept this up for over half an hour (I had to leave). They weren't looking for food it seems. I would think that they're using up an awful lot of energy doing this. What's going on? Are they just out 'crusing' or what? Also there is a stream, a pond, and some ducks here. The ducks are very elegant in flight except, in my opinion, they beat their wings too fast. When they come in for a landing (on the pond) they seem to botch the landings: their wings are stretched out straight, tilt way over one way, then the other way, break quickly, and plop down in the water. Is this typical of duck landings or do they just have problems zeroing in on small ponds? -Dave
sandee@sun16.scri.fsu.edu (Daan Sandee) (12/13/90)
In article <4514@wrgate.WR.TEK.COM== dmunroe@copper.WR.TEK.COM (David Munroe) writes:
==
==The setting: Portland Oregon, early October, about 7pm, in a large weeded
==field (several acres) near a suburban shopping center. I noticed about 50
==to 75 sparrowlike birds, probably larger and darker, clustered together and
==flying in large clockwise circles about 75 feet above the ground. Sometimes
==a few birds would break away, but they'd eventually come back. Sometimes
==several different groups of circling birds would join into one large group.
==What puzzled me is that they kept this up for over half an hour (I had to
==leave).
==
Those were starlings on their roosting flight. Starlings (and various
blackbirds) gather in large, sometimes enormous, flocks and circle around
in the manner you describe before going to roost (sleep) in the weeds.
==Also there is a stream, a pond, and some ducks here. The ducks are very
==elegant in flight except, in my opinion, they beat their wings too fast.
==When they come in for a landing (on the pond) they seem to botch the landings:
==their wings are stretched out straight, tilt way over one way, then the other
==way, break quickly, and plop down in the water. Is this typical of duck
==landings or do they just have problems zeroing in on small ponds?
==
Ducks (and other waterfowl like geese) have a problem in losing altitude when
coming in to land. They could circle round until they finally hit ground,
but they often expedite the process by breaking left/right which causes
them to lose altitude real fast.
You say you don't know about birds but you are a very good observer.
There are many birders that could identify those birds but have never
bothered to see how they behave.
Daan Sandee sandee@sun16.scri.fsu.edu
Supercomputer Computations Research Institute
Florida State University, Tallahassee, FL 32306-4052 (904) 644-7045rcb33483@uxa.cso.uiuc.edu (ArchTeryx) (12/14/90)
dmunroe@copper.WR.TEK.COM (David Munroe) writes: >I apologize if everyone here knows the answer to this, but I don't know >much about birds. Now that rec.autos is in the middle of a flame war, I've >got a chance to post this. :-) >Also there is a stream, a pond, and some ducks here. The ducks are very >elegant in flight except, in my opinion, they beat their wings too fast. >When they come in for a landing (on the pond) they seem to botch the landings: >their wings are stretched out straight, tilt way over one way, then the other >way, break quickly, and plop down in the water. Is this typical of duck >landings or do they just have problems zeroing in on small ponds? The ducks have to beat their wings fast, because they are rather bulky and must maintain a high airspeed to keep aloft. As for the tilting, that too serves a very specific purpose. It is a form of controlled side-slipping to quickly lose altitute. Ducks and geese cannot slow down their airspeed very well, becuase of their high loading curve (they must fly fairly fast to keep from stalling/crashing upon landing). So they have to lose altitute *very* quickly to make a landing on a small pond, yet remain in control to keep from crashing/ injuring themselves. This is called side-slipping by pilots, and is a very useful trick. The birds just evolved it on their own. To answer your above questions, yes, it is typical of both duck and geese landings, and they do that specifcally so they can land on small ponds. -- ------------------------------------------------------------------------------- R. Cody Buchmann ^.^ "Kehaar" "He tell *me* the plan...I *know* the email: rcb33483@uxa.cso.uiuc.edu plan!" -Watership Down. ------------------------------------------------------------------------------
JAHAYES@MIAMIU.BITNET (Josh Hayes) (12/15/90)
In article <4514@wrgate.WR.TEK.COM>, dmunroe@copper.WR.TEK.COM (David Munroe) says: > >The setting: Portland Oregon, early October, about 7pm, in a large weeded >field (several acres) near a suburban shopping center. I noticed about 50 >to 75 sparrowlike birds, probably larger and darker, clustered together and >flying in large clockwise circles about 75 feet above the ground. Sometimes >a few birds would break away, but they'd eventually come back. Sometimes >several different groups of circling birds would join into one large group. >...they kept this up for over half an hour... > It sounds like starling evening flocking behavior. I see this all the time (and, I suppose, most people who live in a populated area do, too). They usually seem to roost communally, but they've been feeding in a rather dispersed pattern. In the evening, they start flying around in a large circle, picking up birds, often for an hour. If you watch for the whole time, you'll notice that while a few birds drop out, more come in, and the final flock is much larger than the initial group. Then they fly off to some nice trees to poop on whatever sits below. (I don't much like starlings, but every once in a while I see a really brightly iridescent male in the sun and they can be strikingly lovely.) >Also there is a stream, a pond, and some ducks here. The ducks are very >elegant in flight except, in my opinion, they beat their wings too fast. >When they come in for a landing (on the pond) they seem to botch the landings: >their wings are stretched out straight, tilt way over one way, then the other >way, break quickly, and plop down in the water. Is this typical of duck >landings or do they just have problems zeroing in on small ponds? Heck, YOU try it. What they have to do, of course, is a controlled stall. Any pilot will tell you that is tricky. And they're usually flying at a deceptively fast speed (i.e. they go faster than you think). Ducks are pretty good, mostly; I've seen a fair number of wading birds do nose-dives on landing...it's kinda endearing, actually. But, also as any test-pilot will tell you, a successful landing is one you survive. Ta. Josh Hayes, Zoology Department, Miami University, Oxford OH 45056 voice: 513-529-1679 fax: 513-529-6900 jahayes@miamiu.bitnet, or jahayes@miamiu.acs.muohio.edu "I am the Supreme Being, you know; I'm not completely dim."