Bird of the Sun
The Arctic tern is known to make the longest annual migration
in the animal kingdom. During its breeding season,
it is found far to the north where summer days are long,
and it winters far south in the southern hemisphere,
where the days are longest during November to February.
This means that the Arctic tern probably experiences more
sun light during a calendar year than any other creature
The long-distance travel of the Arctic tern is well-known
both amongst researchers and in the broader public.
Now, for the first time, technological advances allow us
to follow the Arctic tern on its immense journey,
practically from pole to pole.
This study used miniature archival light loggers (geo-locators)
to map the migration
of the Arctic tern.
The method itself is not novel, and has been used successfully
for more that a decade, but due to the weight of loggers,
studies were limited to large-sized seabirds, such as albatrosses
Within the last couple of years, however, technological development
has allowed these loggers
to be reduced in size and weight, opening up a whole new array
of small to medium-sized birds to such study.
Greenland Institute of Natural Resources.
Interpolated geolocation tracks of 11 Arctic terns tracked
from breeding colonies in Greenland (n = 10 birds)
and Iceland (n = 1 bird).
= autumn (postbreeding)
= winter range (DecemberMarch),
= spring (return)
Two southbound migration routes were adopted in the South
Atlantic, either (A) West African coast (n = 7 birds)
or (B) Brazilian coast. Dotted lines link locations during
The researcher team, from Greenland, Denmark, the United States,
Great Britain, and Iceland, have
successfully mapped the impressive migratory
movements of the Arctic tern. The results of the study verify
what has been supposed for decades: that the Arctic tern does
indeed conduct the longest annual migration
in the world. Every year this small seabird travels an average
of around 71,000 km roundtrip from
Greenland to the Weddell Sea, on the shores of Antarctica,
and back to the breeding grounds in Greenland.
In order to equip Arctic terns
with geo-locators the bird had
to be trapped on the nest.
Breeding Arctic terns were
trapped during incubation in 2007, and caught again
after a full circle of migration
The research results not only confirm the Arctic tern as the
champion of long-distance migration, but also
held a few surprises in store for the research team. It turns
out that the birds do not immediately travel
south, but spent almost a month at-sea in the middle of the
North Atlantic Ocean, approximately 1,000 km
north of the Azores. After this lengthy stop over, the birds
continued their long journey south down the
coast of northwest Africa, but around the Cape Verde Islands
the birds behaviour surprised the researcher
team again. Approximately half of the birds continued down
the coast of Africa, while the other half crossed
the Atlantic Ocean to follow a parallel route south down the
east coast of South America.
All of the birds spent the northern winter months in Antarctic
waters. Interestingly, on their long return
journey the birds did not choose the shortest route back to
their breeding grounds in Greenland. Instead, the
Arctic terns traced out a gigantic S? pattern northward
through the Atlantic Ocean a detour of several
thousand kilometres over a straight line north to their breeding
and pictures in this frame from http://www.arctictern.info/
"The Arctic Tern - Migration Project"