Subject: Re: high-flying birds and hurricanes and vagrancy...
Date: Jan 31 14:46:24 1998
From: Jack Bowling - jbowling at direct.ca


Jerry Converse wrote -

>From some one who knows very little about weather, except what I see.

> In comparison, I have seen clouds moving as fast as commercial
> airplanes. I don't know how high any given bird can fly without taking
> along some oxygen, but if a bird got into a big boomer (strong thermal)
> it can take it up thousands of feet vertical. Then the bird gets into
> one of those "jet streams". Couldn't it sit back and "enjoy the ride"
> like the Nissan commercial. Just a thought.

The most-published high altitude record for bird flight is a flock of
Bar-headed Geese overflying the Himalayas at about 28,000 feet. The problem with
a bird getting swept upward in a thermal at boreal latitudes is that it would
likely encounter frozen precipitation at some point which would not be conducive
to its health. Warm-core systems such as hurricanes do not have much frozen
water in the system so this would not be a problem. However, getting slammed by
one of those huge horizontally-travelling tropical raindrops would likely also
be injurious to a bird's health. IMHO, the only likely way that a bird could
survive the passage of a hurricane is if it:

1) seeks shelter behind some structure with enough solidity to survive the
windforce (the middle of a large tropical forest would be ideal; or behind
some dense structure such as a granite wall, cement building, etc.).
2) lets itself be blown *along with the wind*, thus being in net zero relative
motion to both the storm winds and to the raindrops; risky since any untimely
move that puts it out of zero net motion would likely lead to injury.
3) it gets lucky enough to survive the passage of the convective bands
associated with a hurricane and ends up in the eye of the storm; once inside,
the bird could stay there and follow its horizontal motion with little risk.
4) it senses the storm coming and beats a retreat away from the affected area.

Would be interesting to radio-tag some birds in the path of an incoming
hurricane and see what happens.

- Jack








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Jack Bowling
Prince George, BC
jbowling at direct.ca