Trans-hemispheric migrants: the Great Shearwater
Late in September, one million Great Shearwaters (Puffinus gravis) returned to Gough Island in the South Atlantic having just migrated from their North Atlantic overwintering grounds. Large rafts comprising thousands of individuals sit offshore each evening as the birds wait for sunset. As the sun dipped below the horizon each evening the shearwaters would quietly circle above the coastal tussocks, slow down and prepare to land.
Great shearwaters are supreme aeronauts, not only are they trans-hemispheric migrants that cross the globe twice each year, they also travel 370 - 450km each day during the chick-rearing period.
Now, a few weeks on, eggs have been laid and it is time for the team on Gough Island to check the burrows for the twenty birds that will be destined to carry geolocators. These tiny devices will capture important data on the important foraging areas that these birds use in the austral summer when they breed and the boreal summer when they are not breeding.