2 osprey + fish questions
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frille
Oct 21, 2008, 5:06:06 AM10/21/08
to ospreyworld, lasse....@sr.se
Hello,
I am new on this list. I have two questions:
1. I have heard and read a number of reports of osprey drowning after
not being able to release its´ claws from a fish that was too heavy to
catch. There are also many reports of fish, dead or alive, with
remnants of osprey feet in their back (there is actually a specific
word for this in Swedish, "crown pike"). I have, however, never seen
any proof of this or skeleton samples in any museum. Any information?
2. An old fisherman that I met used to throw fish (mostly perch) into
the water, and it was taken by a male osprey breeding nearby. This
summer he has managed to have the osprey actually grabbing fish
directly from his hand or from a little piece of wood to which the
fish was attached. This was filmed and photographed. Anybody heard
about such a behaviour before?
Sincerely,
Lasse Willén
Journalist, Naturmorgon
Swedish National Radio Co
I am new on this list. I have two questions:
1. I have heard and read a number of reports of osprey drowning after
not being able to release its´ claws from a fish that was too heavy to
catch. There are also many reports of fish, dead or alive, with
remnants of osprey feet in their back (there is actually a specific
word for this in Swedish, "crown pike"). I have, however, never seen
any proof of this or skeleton samples in any museum. Any information?
2. An old fisherman that I met used to throw fish (mostly perch) into
the water, and it was taken by a male osprey breeding nearby. This
summer he has managed to have the osprey actually grabbing fish
directly from his hand or from a little piece of wood to which the
fish was attached. This was filmed and photographed. Anybody heard
about such a behaviour before?
Sincerely,
Lasse Willén
Journalist, Naturmorgon
Swedish National Radio Co
Iasgair
Oct 21, 2008, 7:12:41 AM10/21/08
to ospreyworld
There is no such thing as involuntary lockup on a raptors foot,, any
raptor.
The mechanism is the same for any bird in that in the hallux longus
tendon there is a ratchet that holds the tallons closed as long as the
leg is bent, and the tendon is being pulled,this is the reason that
birds do not fall of their perch when they roost,also sitting on one
foot increases the pressure on the tendon increasing lock,and
relaxing the muscles, the pressure is proportional to the degree of
bend. The bird simply has to straighten the leg for the "lock" to
release the toes can be closed and opend by the extendor muscle on
the front fo the leg. So "lockup" is a mental attitude and not
physical I believe. Raptors are killers/preditors. and hunting is
very expensive in energy costs so they mean to hang on to the catch.
Birds catching fish too heavy for a lift, might swim or bounce the
fish ashore, if this is too far out then the bird might die from
exhausion, In deep water a fish can go down and this should let the
bird straighten its leg and release.
In shallow water, possibly a fish cant go anywhere and the Osprey
might hang on till its exhausted.
Not too sure of the baiting story though they are certainly not shy
and do get quite close to human habitation,
Finally in Alan poole book` Ospreys` , there is a picture , actually
a good picture of a bird taking a lure in 1914 (Staten Island)
Hope this helps
http://www.birdforum.net/showthread.php?t=33000&highlight=carron+valley+osprey
raptor.
The mechanism is the same for any bird in that in the hallux longus
tendon there is a ratchet that holds the tallons closed as long as the
leg is bent, and the tendon is being pulled,this is the reason that
birds do not fall of their perch when they roost,also sitting on one
foot increases the pressure on the tendon increasing lock,and
relaxing the muscles, the pressure is proportional to the degree of
bend. The bird simply has to straighten the leg for the "lock" to
release the toes can be closed and opend by the extendor muscle on
the front fo the leg. So "lockup" is a mental attitude and not
physical I believe. Raptors are killers/preditors. and hunting is
very expensive in energy costs so they mean to hang on to the catch.
Birds catching fish too heavy for a lift, might swim or bounce the
fish ashore, if this is too far out then the bird might die from
exhausion, In deep water a fish can go down and this should let the
bird straighten its leg and release.
In shallow water, possibly a fish cant go anywhere and the Osprey
might hang on till its exhausted.
Not too sure of the baiting story though they are certainly not shy
and do get quite close to human habitation,
Finally in Alan poole book` Ospreys` , there is a picture , actually
a good picture of a bird taking a lure in 1914 (Staten Island)
Hope this helps
http://www.birdforum.net/showthread.php?t=33000&highlight=carron+valley+osprey
frille
Oct 22, 2008, 5:14:10 AM10/22/08
to ospreyworld
Many thanks for valuable information.
Poole says in his book "Ospreys can release fish underwater, casting
doubts on rumors that the birds sometimes drown because they lock onto
fish too big to handle". On the other hand, BWP (Cramps et al) says
(vol II, page 269) "fish usually released if too large, but bird
occasionally drowned if claws get stuck in bones or scales (...).
So the bird involuntarily getting stuck into the fish may be an
explanation. Still, it would be interesting to find some proof of the
"crown pike". Or is it just a myth?
> http://www.birdforum.net/showthread.php?t=33000&highlight=carron+vall...
>
> - Visa citerad text -
Poole says in his book "Ospreys can release fish underwater, casting
doubts on rumors that the birds sometimes drown because they lock onto
fish too big to handle". On the other hand, BWP (Cramps et al) says
(vol II, page 269) "fish usually released if too large, but bird
occasionally drowned if claws get stuck in bones or scales (...).
So the bird involuntarily getting stuck into the fish may be an
explanation. Still, it would be interesting to find some proof of the
"crown pike". Or is it just a myth?
>
> On Oct 21, 10:06 am, frille <lasse.wil...@sr.se> wrote:
>
>
>
> > Hello,
> > I am new on this list. I have two questions:
> > 1. I have heard and read a number of reports of osprey drowning after
> > not being able to release its´ claws from a fish that was too heavy to
> > catch. There are also many reports of fish, dead or alive, with
> > remnants of osprey feet in their back (there is actually a specific
> > word for this in Swedish, "crown pike"). I have, however, never seen
> > any proof of this or skeleton samples in any museum. Any information?
> > 2. An old fisherman that I met used to throw fish (mostly perch) into
> > the water, and it was taken by a male osprey breeding nearby. This
> > summer he has managed to have the osprey actually grabbing fish
> > directly from his hand or from a little piece of wood to which the
> > fish was attached. This was filmed and photographed. Anybody heard
> > about such a behaviour before?
> > Sincerely,
> > Lasse Willén
> > Journalist, Naturmorgon
> > Swedish National Radio Co- Dölj citerad text -
> On Oct 21, 10:06 am, frille <lasse.wil...@sr.se> wrote:
>
>
>
> > Hello,
> > I am new on this list. I have two questions:
> > 1. I have heard and read a number of reports of osprey drowning after
> > not being able to release its´ claws from a fish that was too heavy to
> > catch. There are also many reports of fish, dead or alive, with
> > remnants of osprey feet in their back (there is actually a specific
> > word for this in Swedish, "crown pike"). I have, however, never seen
> > any proof of this or skeleton samples in any museum. Any information?
> > 2. An old fisherman that I met used to throw fish (mostly perch) into
> > the water, and it was taken by a male osprey breeding nearby. This
> > summer he has managed to have the osprey actually grabbing fish
> > directly from his hand or from a little piece of wood to which the
> > fish was attached. This was filmed and photographed. Anybody heard
> > about such a behaviour before?
> > Sincerely,
> > Lasse Willén
> > Journalist, Naturmorgon
>
> - Visa citerad text -
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