adUlt migrations | 55shuttle back and forth between far north and far south on a wing and a
prayer:
The Arctic Tern’s Prayer
Tell the air to hold me in the rushing heart of it
And keep its paths straight
Away from home let there be a land that
Flows with fish and flies
And let it taste like it tasted at home- Mary Anne Clark
With the aid of geolocators, a multinational team secured data on the
tracks of 10 birds from Greenland and one from Iceland.^3 Southbound,
the terns travelled southwest to a stopover region of deep water in the
eastern portion of the Newfoundland Basin and the western slope of the
mid- North Atlantic Ridge between 41– 53°N and 27– 41°W. There they
lingered for 3– 4 weeks. Continuing southward, all 11 birds headed south-
east toward the West African coast. South of the Cape Verde Islands
(~10°N), however, migration routes diverged: seven birds continued to
fly south parallel to the African coast, whereas four others crossed the
Atlantic to follow the east coast of Brazil. (See Map 3.)
Once south of the Cape of Good Hope, there were more east- west
movements but still the terns generally continued to push southward
and spent the austral summer roughly south of 58°S, at the mouth of the
Weddell Sea, where oceanic productivity is high. The S- shaped return
in spring followed a different route to that of autumn. Initially the
terns flew north, until about 30°S. Then they swung left and followed a
north- westerly route across the Equator until reaching tropical waters
east of the Caribbean. Then a right turn took them north, or a little east
of north, back to Greenland and Iceland. That final leg saw the birds
pass back through the area used during the southbound stopover. How-
ever, northbound that area apparently held little interest for the migrat-
ing terns.
The numbers generated from these travels are exhausting. The jour-
ney totalled at least 72,000 km, comprising 35,000 km southbound at