Subject: Re: Pressure changes & birds (was Winter's Coming... & 'dream' birds)
Date: Jan 14 11:25:50 1998
From: jbowling at direct.ca - jbowling at direct.ca


** Michael Dosset wrote -

> Jack and Michael,
>
> I knew that there would be some skeptical people out there! It is
> probably much more complicated than high pressure, and low pressure.
> Others have also caught my oversimplification. Temperature has a LOT to
> do with it, but assuming that the temperature stays the same, I do think
> that there is a difference in the amount that the birds need to consume.
>
> First, I suppose I must tell you all where I got my information. There
> was a recent thread on one of the falconry lists that I am on, and it
> dealt with how the falconers and rehabbers on the list noticed this in
> their captive raptors. When there was high pressure, they would hold
> their weight for days, and when there was a sudden low pressure front,
> they would need more to maintain what falconers refer to as the birds
> "flying weight". I made the assumption that this was also probably true
> for wild birds.

This assumption may not be true i.e. "kept" birds may not exhibit the same traits
as wild birds. Here is a theory: Captive birds sense an incoming storm. They
cannot find food for themselves. The bird becomes more "nervous" i.e. metabolic
rate increases and weight decreases more rapidly than is normal. Since this may
be an artefact of being kept in captivity, it would be interesting to hear from
those with knowledge of the Stuart & Belle tapes whether they tended to hunt more
during or just before lousy weather than at other times.

> As for the type of high, or type of low, and any precip that might come
> with it, you must remember that temperature is a major factor, and these
> birds were also shielded from the elements.

Right. Temperature would not be a factor here.

> Does this help?

Yep. Puts it in context.

- Jack



Jack Bowling
Prince George, BC
jbowling at direct.ca