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Thanks for the response.  I'd be inclined to go for the physiological 
shock or stunning myself, but it does seem odd that the effect should 
abruptly cease at precisely the moment the hawk loosened its grip to 
take off.

I also wonder why this particular behavior should have to be 
physiological, but the "broken wing" diversion by grouse and other birds 
is obviously not.

So my mind remains open on the question...

Cowbirds have a terrible effect, but they're just doing what they need 
to do to earn a living, so I have a hard time "hating" them.  I've also 
seen cowbirds do a variety of interesting things like this that aren't 
so easily explained by physiology and have caused me to have some 
respect for their birdbrains.

For instance, in many hours of assisting and observing at bird-banding 
stations for both dickey birds and hawks, I only once saw a bird 
vigorously and persistently try to remove the band on its leg when it 
was released, and that was a cowbird.  So it's a bird I'd love to see 
experimental researchers do some work with.

Jane
Shoreham

Michael Blust wrote:

> I do not know what mechanism resulted in the behavior you observed.
> I suspect physiological shock or perhaps being physically stunned.
> Many of us have seen birds stun themselves by hitting windows and
> appear dead, only to suddenly fly away.  It is possible the hawk
> wound up stunning the cowbird during the capture.  Since this is not
> (as far as I know) a regular behavior, all I can do is speculate.  In
> any case, I too would have cheered for the hawk and would have
> admired (though not necessarily cheered) the "pluck" of the cowbird
> who avoided "the pluck".
> 
> Michael Blust Dept. of Science Green Mountain College Poultney, VT
> 
> 
> ________________________________
> 
> From: Vermont Birds on behalf of Jane Stein Sent: Sun 2/4/2007 9:06
> AM To: [log in to unmask] Subject: Re: [VTBIRD] Pigeon -- Rock Dove
> Rescue
> 
> 
> 
> Michael, I couldn't possibly agree more with what you say here.
> 
> Just to be clear, though, which of the possible explanations for the 
> "playing dead" behavior is most likely is not a discussion I was
> trying to enter into.
> 
> Also to be quite clear, I am vehemently opposed to the kind of 
> sentimentalizing and gross anthropomorphizing one sometimes hears
> about bird (and animal) behavior.  But on the other hand, I don't buy
> into the opposite idea, that critters are just little cookie-cutter
> automatons with zero awareness and zero ability to observe, draw
> conclusions, act on the conclusions and learn from experience.  I
> think their ability to do that is certainly limited, but not
> altogether absent, and that we sometimes twist ourselves into real
> pretzels trying to find explanations for behavior that rely
> exclusively on physiology and/or genetic programming.
> 
> It is the job of scientists like you and Bill to do the work that 
> laboriously teases out the mechanisms for those responses.  It is our
>  job, I think, to learn from you.  But it's also our pleasure to
> observe and enjoy and marvel at what we see, whatever the mechanism
> is that produces it.
> 
> Do you know, or does anybody know, what the mechanism is for the 
> "playing dead" behavior I observed?  I've seen a fair number of hawk 
> prety captures, and I've never seen it any other time.  I've seen 
> captured prey become very still and I've seen them struggle
> violently, but I've never before or since seen one do what this
> cowbird did.  It's the only time I've happened to see a hawk grab a
> cowbird, so I have no idea whether this is typical particularly of
> cowbirds or a rare miraculous (for the cowbird) coincidence of
> nerve-pinching released at precisely the right moment.  Without
> further data, there's no way to make more than a wild guess.
> 
> Whatever the mechanism, it was a wonderful thing to see.  Being a
> hawk person, I confess I cheered when the little Sharpie blasted into
> the ball of blackbirds and came out the other side with lunch.  But
> then I also had to cheer when the cowbird abruptly escaped what
> appeared to be his fate.
> 
> Jane Shoreham
> 
> 
> 
> Michael Blust wrote:
> 
>> It does make a difference in terms of whether the response was an 
>> instinctive response, an intellectual response, or a physiological 
>> response.  For instance, potential explanations might include that 
>> the bird had temporarily gone into shock, that the hawk was
>> pinching on a nerve that rendered the prey temporarily helpless,
>> that the playing dead behavior was instinctive (and thus largely
>> genetic and therefore could be inherited), or that the playing dead
>> behavior is learned and thus not subject to direct inheritance.
>> These all have different implications for both the behavior of the
>> predator and the prey.  They also have implications for
>> heritability and therefore evolution of the behavior.
>> 
>> In science, if you have one explanation that is supported by the 
>> evidence, you may be right.  If you have four explanations and the 
>> evidence ONLY supports the one, you have a much stronger argument. 
>> That is why Bill emphasizes to his students the importance of 
>> alternative explanations.  Thinking of alternatives is part of the 
>> "art" of science, but as with all art, some people are into the 
>> technical aspects, and others just enjoy what they experience.
>> Both have their place.  And many of us enjoy both.
>> 
>> Michael Blust Dept. of Science Green Mountain College Poultney, VT
>> 
>> 
>> ________________________________
>> 
>> From: Vermont Birds on behalf of jane Sent: Sat 2/3/2007 9:54 PM
>> To: [log in to unmask] Subject: Re: [VTBIRD] Pigeon -- Rock Dove
>> Rescue
>> 
>> 
>> 
>> Um, how is that different from what I said?  I made no assumptions,
>>  the bird clearly was "playing dead."  That observation doesn't 
>> preclude an instinctive response-- although I do think we sometimes
>>  bend so far over backwards to try to explain away bird and animal 
>> behavior as hard-wired "stumulus-respose" that we encroach pretty
>> far beyond Occam's razor.
>> 
>> The bird played dead.  *Why* it played dead is not something I 
>> speculated on, but others are certainly free to.
>> 
>> Jane Shoreham
>> 
>> 
>> William H. Barnard wrote:
>> 
>> 
>> 
>>> Jane's comments might be totally correct, but I would like to 
>>> suggest to readers that observations in nature often have
>>> multiple explanations. Jane's explanation is one of many that
>>> might explain her observation. I do not believe that cowbirds or
>>> other birds have the cognative powers to "play dead" when
>>> attacked by a hawk.  Much as we might like to think that our
>>> birds have that ability, research might suggest that they are
>>> more "creatures of the moment" and live their lives, for the most
>>> part, by responding in very stereotyped behaviors to stimuli.
>>> Evidence of a thought process or learning in birds is present in
>>> the literature but not the norm.
>>> 
>>> I always try to teach my students to look for alternative 
>>> explanations and not grab the one's that are often driven by 
>>> anthropomorphism.
>>> 
>>> Bill Barnard
>>> 
>>> 
>>> 
>>> -----Original Message----- From: Vermont Birds 
>>> [mailto:[log in to unmask]] On Behalf Of jane Sent: Saturday, 
>>> February 03, 2007 6:59 PM To: [log in to unmask] Subject: Re: 
>>> [VTBIRD] Pigeon -- Rock Dove Rescue
>>> 
>>> Great story!  I read/saw somewhere that although Rock Doves may 
>>> look stupid, they've exhibited the greatest cognitive ability of 
>>> any bird, including crows, researchers have tested.  It one of 
>>> those studies involving pecking the right picture to get a food 
>>> pellet, and the Rock Doves quickly learned to distinguish between
>>>  photographs and artwork, and then actually between artists.  If
>>> I remember right, it was something like Picasso and Monet they 
>>> ultimately tested them on.  Hard to believe.
>>> 
>>> Some winters ago, I saw a little male Sharpie plunge into one of 
>>> those big balls of blackbirds in a farm field in Addison and come
>>>  out the other side with what looked like a cowbird in his claws.
>>>  He took it over to a nearby barn roof and sat down with it and 
>>> pulled a couple of feathers.  The cowbird was completely splayed 
>>> out, limp, head fallen back, wings open and drooping, looked
>>> quite dead.
>>> 
>>> Then the Sharpie decided he didn't want to have his lunch with me
>>>  watching, I guess, and lifted off to go somewhere else.  He must
>>>  have loosened his grip just for a second because the cowbird 
>>> instantly came to life, jerked free and dove down out of my
>>> sight. Sharpie learned a lesson, I think.  I didn't know birds
>>> would play dead to that extent. The cowbird wasn't just still, it
>>> let itself go completely limp in the hawk's talons and just
>>> waited for a lapse of concentration.
>>> 
>>> Jane Shoreham
>>> 
>>> 
>>> 
>>> 
>>> William Gilbert wrote:
>>> 
>>> 
>>> 
>>> 
>>>> While watching a large flock of some 35 rock doves ground
>>>> feeding a
>>> 
>>> hawk
>>> 
>>> 
>>> 
>>>> flashed into view and took one of the suddenly fleeing Rock
>>>> Doves to
>>> 
>>> the
>>> 
>>> 
>>> 
>>>> ground. The others all disappeared to a roof top they favor.
>>>> 
>>>> As the Hawk prepared to dine while standing on the pigeon and 
>>>> plucking feathers, the captive, coming back to life, broke
>>>> loose and tried to
>>> 
>>> escape.
>>> 
>>> 
>>> 
>>>> It made it into the air about 25 to 30 feet with the hawk in
>>>> hot
>>> 
>>> pursuit,
>>> 
>>> 
>>> 
>>>> when the flock appeared again and flew into the path of the two
>>>>  birds.
>>> 
>>> In
>>> 
>>> 
>>> 
>>>> the confusion the hawk lost its prey.
>>>> 
>>>> Sure looked like a rescue.
>>>> 
>>>> 
>>>> 
>>> 
>>> 
>>> 
>>> 
>> 
> 
>