Subject: Re: Video footage of marbled murrelets at the nest
Date: Jan 13 13:17:33 1998
From: Michael Price - mprice at mindlink.bc.ca


Hi Tweets,

Jerry Tangren writes, re Marbled Murrelets fledging directly to ocean from
nests often far inland :

>Just a wild guess, but the ocean reflects a different color off the sky
>than land does. I've heard that South Sea Islanders can navigate their
>boats from island to island by observing the color of the sky.

But Janet Hardin writes:

>Chicks usually fledge at dusk.

Interesting! In trying to resolve these two points in my mind, at first, I
thought they'd simply be orienting to the light and heading to it, but the
place where the last glow of twilight--so a differently-colored stretch of
sky--would be at that time of year could be as much as another 45 degrees to
the NW of the direction they'd need to take to arrive as they do at the
stretch of ocean directly opposite the nest. Maybe Jerry's right, that they
look for light indicators--which would imply they'd not fledge in dull
overcast, or maybe would, but earlier in the day--but they then subtract
30-45 degrees for Kentucky windage. Given their bullet flight, even those
nesting far inland are still only an hour or two at most from the ocean, and
if they head even vaguely west they'll still hit ocean.

So, then, another question arises: are the birds which are on the ocean
directly offshore from their nests, that is, are the water territories at
the shortest straight-flight distance from the nest?

Michael Price A brave world, Sir,
Vancouver BC Canada full of religion, knavery and change;
mprice at mindlink.net we shall shortly see better days.
Aphra Behn (1640-1689)