rising@utzoo.uucp (Jim Rising) (08/25/89)
When I was a kid, before Peregrines were rare, I recall watching, one spring, as a Peregrine apparently attempted to grab a Golden Plover from a flock. As I recall the incident, the Peregrine stooped on the flock and actually flew around it a couple of times, then left, without a catch. None of the plovers broke from the flock, and I assumed that the falcon was "reluctant" to charge into it at over 100 mph (or whatever). We should say, of course, that there is selection against Peregrines that do. --Jim Rising -- Name: Jim Rising Mail: Dept. Zoology, Univ. Toronto, Toronto, Ontario, Canada M5S 1A1 UUCP: uunet!attcan!utzoo!rising BITNET: rising@utzoo.utoronto.bitnet
dune@cbnewsl.ATT.COM (Greg Pasquariello) (08/25/89)
In article <1989Aug24.193532.6535@utzoo.uucp> rising@utzoo.uucp (Jim Rising) writes:
:When I was a kid, before Peregrines were rare, I recall watching,
:one spring, as a Peregrine apparently attempted to grab a Golden
:Plover from a flock. As I recall the incident, the Peregrine
:stooped on the flock and actually flew around it a couple of
:times, then left, without a catch. None of the plovers broke
:from the flock, and I assumed that the falcon was "reluctant"
:to charge into it at over 100 mph (or whatever). We should say,
:of course, that there is selection against Peregrines that do.
:--Jim Rising
:--
:Name: Jim Rising
About two years ago, I witnessed some interesting behaviour of starlings
that were being attacked by a merlin. The starlings were in the air near
a tower. When the merlin was spotted, the starlings didn't split up, but
immediately formed a compact flock that flew right onto the tower. The
merlin then made a couple of weak passes at the tower of plenty, and left.
Greg Pasquariello
...!att!picuxa!gpasqmjm@oliven.olivetti.com (Michael Mammoser) (08/26/89)
In article <1989Aug24.193532.6535@utzoo.uucp>, rising@utzoo.uucp (Jim Rising) writes: > When I was a kid, before Peregrines were rare, I recall watching, > one spring, as a Peregrine apparently attempted to grab a Golden > Plover from a flock. As I recall the incident, the Peregrine > stooped on the flock and actually flew around it a couple of > times, then left, without a catch. None of the plovers broke > from the flock, and I assumed that the falcon was "reluctant" > to charge into it at over 100 mph (or whatever). We should say, > of course, that there is selection against Peregrines that do. I was informed through email that my statement of belief that peregrines would not strike into a flock for fear of injury in a collision, was in itself anthropocentric; implying an ability in the bird to make a concious judgement about the danger involved, rather than reacting unconciously to genetically determined instincts. I must admit that I had not thought about this when writing the story, but it started me thinking about the differences between instinctive behavior and conditioned responses. Certainly a peregrine that strikes into a flock and is seriously or fatally injured would have little success reproducing its kind. This would make one believe that the population will tend towards birds that don't behave this way. But what about the occasional bird that happens to survive such a maneuver with little injury; able to recover and go on with its life? Couldn't it learn from this experience and avoid making the same mistake? And wouldn't its avoidance of this maneuver on future occasions be a concious, rather than instinctive, act? I certainly don't have any expertise in this area, but I'm interested in the opinions of others on the net. As a lay-person, I seem to recall reading about some instances of learned behavior in wild animals. The one that springs to mind is about juvenile Blue Jays that try their hand at eating Monarch Butterflies, only to learn that these poisonous beauties are to be avoided. Mike
geleynse@hppad.HP.COM (Martin Geleynse) (09/06/89)
With respect to the "request for comments" on falcon learning and the
response of falcons to the flocking behaviour of some prey species,
by mjm@oliven.olivetti.com (Michael Mammoser): I have observed this
predator avoidance technique a number of times in reaction to both
wild falcons, and those trained for falconry.
Several years ago I trained and flew a Merlin at startlings and
cowbirds which flock in early fall. Any time there were more than a
few individuals, the quarry would invariably form a tight "pack" an
fly in swirling circles. They would gradually make their way to some
dense cover, usually standing corn, which they would then dive into.
I noticed that the position of any one individual within the flock
was constantly changing. Individuals on the outside edge would be
"swallowed up" by a wave of birds from the top of the flock, for
example.
My Merlin would enter these flocks repeatedly, but she was never
successful. With small groups of startlings, she could single out
one, and fly it down. Her success rate in these instances was
somewhere around 20%. As the season wore on she stopped entering the
large swirling masses of birds. Rather, she would "pace" them until
they reached cover. I am sure that, if a small group had broken away
from the flock, she would have persued with vigor. However, none ever
did.
I am leading up to two points:
1) Falcons are able to "learn" by trial and error experience, and
modify there hunting techniques accordingly.
2) Experienced birds do not enter large flocks of prey because they
have learned that, as long as the flock is in formation, there is
essentially no chance of success.
(In addition, it is very unlikely that a falcon could be hurt by striking
a bird a small as a plover. They will quite happily pile into something
as large as a Mallard duck with no ill effects.)
The "learning" or refinement of hunting techniques is well
documented. I refer those interested to the book "Fledgling
Behaviour of Peregrine Falcons" by Steve Sherrod. The fact that I can
release my Peregrine, which immediately climbs several hundred feet
into the air and circles directly above my dog pointing a covey of
partridge for ten minutes, until I arrive to flush, is further evidence of
a falcons ability to adapt its hunting behaviour, at least within limits.
Of course, during the entire training procedure, I do not beleive the
falcon used any abtract reasoning ability, rather, it formed an
increasingly stronger association between "correct behaviour" (go
high, watch dog) and desired result (dinner).
The observations of shallow stoops by a Peregrine on shore birds may
be explained in 2 ways:
1) The falcon has, through trial and error, learned that this behaviour
sometimes causes a few shorebirds to separate from the flock, and
thus become catchable. (pretty abstract - not likely).
2) The falcon is singles out a bird on the edge of the flock, stoops,
but looses sight of it in the flock before completeing the stoop.
Not having any quarry in sight, and having previously associated
altitude with success, it pulls out of the stoop. (probably closer
to the truth)
There's my two cents anyway,
Martin