Lawrie Conole wrote:
>
> On Wed, 12 Mar 1997, Gil Langfield wrote:
>
> > in the sky were hundreds of swifts, so high that I had great difficulty
> > discerning which of the two species they were. With a lot of imagination,
> > some of them seemed to have white under the rump and so they were probably
> > all Needletails.
> > 1. How high were these swifts, and how many are sucked into the engines of
> > the jets on their long approach over Toolangi to Melbourne Aiport?
>
> Can't answer this one; but I guess they'd be snap-frozen if they were more
> than a few thousand metres up.
>
> ==============================
> Lawrie Conole
> Geelong, Victoria, Australia
>
>
> ==============================
Although I don't have the details in front of me at the moment, there have been
quite a
few bird species recorded flying at very high altitudes, particularly over
mountain
ranges.
I remember reading some scientific papers in the mid 1980s which suggested that
some
small bird species that encounter very low oxygen levels and temperatures
during their
migration may periodically go into torpor while soaring on air currents. A
torpid bird
lowers its metabolic rate (very much like an animal going into hibernation but
for much
shorter time periods) and this would help reduce oxygen demand, expenditure of
fat
reserves and excessive heat loss from the bird's body.
Dr Stephen Ambrose
RAOU Research and Conservation Manager.
*********************************************
Royal Australasian Ornithologists Union.
Australian Bird Research Centre,
415 Riversdale Road,
Hawthorn East,
VIC 3123.
Tel: (03) 9882 2622.
Fax: (03) 9882 2677.
Email: S.Ambrose <>
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