inger vandyke wrote:
I am certainly no expert but I believe it has something to do with the birds timing their migration wrong with the change of ocean temperatures on currents. Naturally the cooler water temps bring more food but if there is a sudden burst of warm water I think that means they arrive, expecting cold water and more food, find warm water and nothing to forage on, then die off in their thousands.
That's certainly a plausible explanation, Inger. There is an El Nino
weather pattern developing,
with sea surface temperatures in the central Pacific ocean currently up
to 2 deg. C above normal,
and the warmest since 2002.
http://www.bom.gov.au/climate/enso/
El Nino events are also marked by weakened Trade Winds. A head wind -
or the absence of
a tail wind - could make all the difference to a long-distance migrant.
I suspect this may be less
of a problem for shearwaters who (in theory) have more refueling
opportunities than, say, curlews.
It would be interesting to compare historical shearwater wrecks with El
Nino events.
--
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Paul Taylor Veni, vidi, tici -
I came, I saw, I ticked.
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