js2j@mhuxt.UUCP (sonntag) (01/09/85)
While driving across Pennsylvania this fall (around September), I saw
what appeared at first to be a large swarm of bees hovering and flying back
and forth, changing directions, etc. I soon realized that this was merely
a trick of perspective and that it was actually a flock of small birds about
300 yards away. This behavior seemed so strange to me that I stopped the car
on the edge of I-80 to watch. Once I had stopped, I could see that there was
one larger bird (~crow or hawk sized, it was too far for me to tell) that
seemed to be leading the flock back and forth and up and down. After observing
for a short while, I realized that the flock of small birds was CHASING the
large bird all over the place. The small birds could fly faster than the
large bird, and would almost catch up to it when the large bird would change
direction suddenly, gaining a few yards of lead.
I was wondering if maybe the bird watchers and naturalists who frequent
this newsgroup would be able to explain this behavior. Like:
1.) What could the large bird have done to get so many small birds
so pi**ed off at it?
2.) How come the small birds were faster and less manueverable than the
large bird? I would have expected the opposite.
3.) What would the small birds have done, had they succeeded in catching
the large bird?
4.) Don't they have better things to do?
I always thought of small birds as peaceful insect eaters. These seemed
almost Hitchcockian.
--
Jeff Sonntag
ihnp4!mhuxt!js2j
"Step right up, get your free TANSTAAFL!"winkg@vice.UUCP (Wink Gross) (01/10/85)
Small birds often "mob" much larger hawks, owls, crows, and ravens. Evidently they recognize their (perceived) enemies. For that matter crows often mob hawks and owls, too. What's ironic is that the smaller birds mob large, slow-moving buteos which don't normally prey on birds at all. I've never seen birds mob an accipiter or falcon, which would prey on small birds. (I once saw a single Goshawk attack 6 or 7 ravens; I'm not sure what to do with that data point.) Anyway, next time you're walking in the woods and come upon a flock of small birds making a lot of noise up in the trees be sure to stop and take a close look. The center of attention may be an owl or hawk! Wink Gross Tektronix, Inc.
fowler@uw-beaver (Rob Fowler) (01/10/85)
> 1.) What could the large bird have done to get so many small birds > so pi**ed off at it? Birds are very territorial. Merely approaching nesting areas can set off this kind of behavior. Around here the swallows will attack any larger birds that come around. Crows will harass owls to death. I once saw a group of crows hounding a bald eagle. When the crows were coming in on an attack run the eagle did a roll to greet the attacker with its talons. The crows break off the attack rather than get hurt, but continually having to defend itself the eagle seemed to be tiring rapidly. I don't know whether the eagle got away or not because they all flew out of sight. > 2.) How come the small birds were faster and less manueverable than the > large bird? I would have expected the opposite. When swallows attack crows (and I presume other large birds) their attack runs are very fast dives and I guess they lose maneuverability at high speeds. > 3.) What would the small birds have done, had they succeeded in catching > the large bird? Again, when swallows attack, they crash dive beak first into the back of the larger bird. Judging by the desparate screams of the crows this must hurt like hell. I don't know whether they actually kill the larger bird, but it's likely that it'll never return to the area. > 4.) Don't they have better things to do? What's more useful than defending home and family from predators? -- Rob Fowler
furuta@uw-beaver (Richard Furuta) (01/17/85)
On the west side of Seattle is a park where people often fly those radio-controlled gliders with the five foot wing spans. I once had the interesting experience of watching two gulls trying to "mob" one of the gliders in a very tentative way. --Rick
ma4cc@sdcc3.UUCP (ma4cc) (01/20/85)
In Chicago I once saw an Eastern Kingbird attack a
Green-backed Heron by actually landing briefly on the back
of the larger bird as it was flying past the Kingbird's
territory. Unfortunately, the 2 birds disappeared around
the edge of a small island at that point, so I was unable to
see how long the Kingbird was able to stay with the heron.
I presume the ride was a short one.
In a similar vein, I once observed a Common Grackle
patiently watching an American Bittern stalk minnows. The
instant the bittern struck a fish, the grackle dropped down
to peck viciously at the back of the bittern's head. The
bittern was obviously startled, but did not drop its meal;
and the grackle retreated at once. I've always been
impressed at the cleverness of this effort by the grackle to
procure fish from water too deep for it to wade in.
_____________________________________________________
Tim McLarnan, ..sdcc3!ix264