I wonder if the Lesser Yellowlegs entertaining the twitchers at
Jerseyville had a problem with its internal clock ...
LK
http://www.int.iol.co.za/index.php?set_id=1&click_id=143&art_id=nw20080131224557229C101213
Study suggests birds can truly navigate
February 01 2008 at 10:26AM
London - Eurasian reed warblers captured during migration and then
dumped 1 000km off course were able to find their way back to their
original route, according to a study suggesting some birds can truly
navigate.
This means that the birds could identify at least two co-ordinates
roughly corresponding to geographic latitude and longitude and
suggests they are not limited to north-south direction as some had
thought, the researchers said on Thursday.
"This finding is surprising and presents a new intellectual challenge
to bird migration researchers, namely which cues enable birds to
determine their east-west position?" Nikita Chernetsov at the
Zoological Institute in Russia wrote in the journal Current Biology.
The researchers found that after dropping the warblers off 1 000
kilometres east, the birds somehow corrected their direction by
shifting their orientation to get back on the correct path home.
Other studies have suggested that birds use the position of the sun or
geomagnetic information to determine latitude, which defines north or
south location, the researchers said.
The Russian team said migrating birds such as the warblers might rely
on two internal clocks, one to set their "home time" and the other to
their wintering grounds. Geomagnetic information might also play a
role, they said.
"We have experimentally shown beyond reasonable doubt that long-
distance, intercontinental avian migrants can correct for east-west
displacements during their return migration in spring," Chernetsov
wrote.
"This means that they can determine geographic longitude, even though
we do not currently know how they do it."
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