Circling for rodents?

"Bill Daniels" wrote in message news:aa4Fc.11095$7t3.8707@attbi_s51...

Most hawks circling low are looking for rodents, not lift.

Bill Daniels


But many times I have shared thermals with Hawks at high altitude.
How did they get there if not by working thermals at low altitude? I
have never been in a thermal with a Red Tailed Hawk that didn't seem
to be trying to optimize climb rate. Turkey Vultures are a different
story. They seem to be happy with any sloppy thermal technique as
long as they maintain altitude.


Andy

Gulls will circle in sink just to lure the unsuspecting soaring pilot.

"Andy Durbin" wrote in message
om...
"Bill Daniels" wrote in message
news:aa4Fc.11095$7t3.8707@attbi_s51...

Most hawks circling low are looking for rodents, not lift.

Bill Daniels


But many times I have shared thermals with Hawks at high altitude.
How did they get there if not by working thermals at low altitude? I
have never been in a thermal with a Red Tailed Hawk that didn't seem
to be trying to optimize climb rate. Turkey Vultures are a different
story. They seem to be happy with any sloppy thermal technique as
long as they maintain altitude.


Andy

(Andy Durbin) wrote in message . com...
"Bill Daniels" wrote in message news:aa4Fc.11095$7t3.8707@attbi_s51...

Most hawks circling low are looking for rodents, not lift.

Bill Daniels


But many times I have shared thermals with Hawks at high altitude.
How did they get there if not by working thermals at low altitude? I
have never been in a thermal with a Red Tailed Hawk that didn't seem
to be trying to optimize climb rate. Turkey Vultures are a different
story. They seem to be happy with any sloppy thermal technique as
long as they maintain altitude.


Andy

Andy,
My theory is that all the large and small raptors mostly go soaring
for the fun of it, just as we do. On occasion they thermal and run
while migrating like the large groups of Broad-Wings (50-100) observed
in September along the Appalachian ridges. I believe that after
catching their prey for the day most of the hawks we encounter just
enjoy the soaring conditions. Some years back I was flying the
cooling tower thermal of a nuclear power plant in NC when I noticed 4
or 5 buzzards circling above at around 5,500'. They got closer to the
well-developed base of the Cu above and then all disappeared
continuing their circle. I watched the bottom of the cloud until I
reached it and never did see them again. Relating the story to Karl
Striedieck he didn't seem surprised and explained that it is quite
normal for them to climb to the top of lift in the cloud and then cut
out to the side. I did not follow them.
They do have a couple millions of years of experience on us.
Herb, J7

you must be sharing thermals with the ones going out for dinner... cross
country

BT

"Andy Durbin" wrote in message
om...
"Bill Daniels" wrote in message
news:aa4Fc.11095$7t3.8707@attbi_s51...

Most hawks circling low are looking for rodents, not lift.

Bill Daniels


But many times I have shared thermals with Hawks at high altitude.
How did they get there if not by working thermals at low altitude? I
have never been in a thermal with a Red Tailed Hawk that didn't seem
to be trying to optimize climb rate. Turkey Vultures are a different
story. They seem to be happy with any sloppy thermal technique as
long as they maintain altitude.


Andy

Does anyone have an idea of how the birds know where to thermal? Do
they have a vario? Where is it? Where is its capacity?
Assuming they breath while thermalling, then I doubt they use their
lungs as capacity... or maybe they stop and sense the air coming out
their noses.
Just wondering...

Uri 4XGJC

(Andy Durbin) wrote in message
. com...
"Bill Daniels" wrote in message news:aa4Fc.11095$7t3.8707@attbi_s51...

Most hawks circling low are looking for rodents, not lift.

Bill Daniels


But many times I have shared thermals with Hawks at high altitude.
How did they get there if not by working thermals at low altitude? I
have never been in a thermal with a Red Tailed Hawk that didn't seem
to be trying to optimize climb rate. Turkey Vultures are a different
story. They seem to be happy with any sloppy thermal technique as
long as they maintain altitude.


Andy

It's a well known fact that birds bones are very light and filled with
holes, just like we have sinuses in our head bones. I've pondered how birds
might sense rate of climb many times and I now hold the view that they sense
it via the cavities in their bones - this would provide them with a very
sensitive variometer, the capacity being automatically incorporated so to
speak.

I'm also convinced that birds soar for pleasure as well as because they
might have to (e.g. Pelicans soar when they are migrating and follow similar
climb/glide patterns to us).

I once observed a seagull from the restaurant at the top of the OMPI
building in Geneva - a seagull was already soaring near the ITU building
when suddenly another shot past the window in a fast glide headed straight
for a point below the other seagull, when it got there it pulled up into the
climb underneath the other gull turning in the same direction. Obviously
his/her CSI (Chief Seagull Instructor) had made the point about proper
thermal entry.

Rgds,

Derrick Steed
Does anyone have an idea of how the birds know where to thermal? Do
they have a vario? Where is it? Where is its capacity?
Assuming they breath while thermalling, then I doubt they use their
lungs as capacity... or maybe they stop and sense the air coming out
their noses.
Just wondering...

Uri 4XGJC

(Andy Durbin) wrote in
message
news:...
"Bill Daniels" wrote in message news:...

Most hawks circling low are looking for rodents, not lift.

Bill Daniels


But many times I have shared thermals with Hawks at high altitude.
How did they get there if not by working thermals at low altitude? I
have never been in a thermal with a Red Tailed Hawk that didn't seem
to be trying to optimize climb rate. Turkey Vultures are a different
story. They seem to be happy with any sloppy thermal technique as
long as they maintain altitude.


Andy

did you ever feel the aileron twitch.. and instinctively know that the
thermal was to your left or right? with most soaring birds (raptors).. those
fingertip feathers tend to move freely.. sensing every movement of the air..
watch one some time..

as for locating thermals?? some believe they can "see the heat".. ever watch
heat rise of pavement.. that "shimmering" as the heat rises.. perhaps our
raptor friends have better vision than we give them credit for

BT


"Uri Saovray" wrote in message
m...
Does anyone have an idea of how the birds know where to thermal? Do
they have a vario? Where is it? Where is its capacity?
Assuming they breath while thermalling, then I doubt they use their
lungs as capacity... or maybe they stop and sense the air coming out
their noses.
Just wondering...

Uri 4XGJC

(Andy Durbin) wrote in message
. com...
"Bill Daniels" wrote in message
news:aa4Fc.11095$7t3.8707@attbi_s51...

Most hawks circling low are looking for rodents, not lift.

Bill Daniels


But many times I have shared thermals with Hawks at high altitude.
How did they get there if not by working thermals at low altitude? I
have never been in a thermal with a Red Tailed Hawk that didn't seem
to be trying to optimize climb rate. Turkey Vultures are a different
story. They seem to be happy with any sloppy thermal technique as
long as they maintain altitude.


Andy

It's a well known fact that birds bones are very light and filled with
holes, just like we have sinuses in our head bones. I've pondered how birds
might sense rate of climb many times and I now hold the view that they sense
it via the cavities in their bones - this would provide them with a very
sensitive variometer, the capacity being automatically incorporated so to
speak.

Some work was done in the early 70's on this. Whatever a bird's "vario" is, it resides in
their ear. Cutting the 8th cranial nerves (which connect the ear to the brain)
extinguished their ability to sense altitude. This work was done in pigeons, (not soaring
birds, who would be expected to have an even better "vario"). Further work (done in a
pressure chamber) indicated that even a pigeon can sense an ambient pressure change
equivalent to climbing 2 feet.

I'm also convinced that birds soar for pleasure as well as because they
might have to (e.g. Pelicans soar when they are migrating and follow similar
climb/glide patterns to us).

Other research done in the 70's was carried out by a glider pilot in Africa. He wanted to
figure out where all the buzzards went during the middle of the afternoon (all would
disappear every day). They thermaled up, out of sight from the ground. Either for
pleasure,or to cool off?

"Jim Skydell" wrote in message
...
Other research done in the 70's was carried out by a glider pilot in Africa.
He wanted to
figure out where all the buzzards went during the middle of the afternoon (all
would
disappear every day). They thermaled up, out of sight from the ground. Either
for
pleasure,or to cool off?

Or simply because it takes little energy and makes them temporarily safe
from all ground-bound predators?

Vaughn

On 4 Jul 2004 14:20:05 GMT, Derrick Steed
wrote:

I once observed a seagull from the restaurant at the top of the OMPI
building in Geneva - a seagull was already soaring near the ITU building
when suddenly another shot past the window in a fast glide headed straight
for a point below the other seagull, when it got there it pulled up into the
climb underneath the other gull turning in the same direction. Obviously
his/her CSI (Chief Seagull Instructor) had made the point about proper
thermal entry.

I've noticed that gulls joining a thermal will almost always circle
the same way as the birds or gliders already in it. I've had them join
me when I was the sole occupant of the thermal and they have always
respected my turn direction. I wish I could say the same about the
small raptors around Cambridgeshire - they often join going the wrong
way and keep a pretty poor lookout too.

Judging from what I've seen from the ground kites and vultures have
better thermalling manners than their smaller relatives. That said,
back in the late '70s I remember seeing a stationary thermal in Jaipur
over the local abattoir that was stuffed with several hundred Indian
vultures. They were flapping up to join at 100 ft or so and riding it
to at least 1000 ft before peeling off in a skein that crossed the
city to another thermal - a magical sight. I wasn't a glider pilot
then, but I remember that a few were turning the wrong way. Sadly, I'm
told that this sight has now vanished from Indian skies. 95% of the
vultures have been killed by a now-common veterinary medicine and the
farmers are learning the hard way just how much cleaning up the
vultures did for them.

--
martin@ : Martin Gregorie
gregorie : Harlow, UK
demon :
co : Zappa fan & glider pilot
uk :