A blue heron known as Gerrit, one of six herons fitted with transmitters to track migration routes, is back in the Netherlands after wintering in Sierra Leone, Nos tv reports on Wednesday.

Little is known about where herons go during the winter months. Ten herons were originally included in the research but four of the satellite transmitters have stopped working.
The research so far shows that herons born in the Netherlands spend two years in Africa before making the return journey.
Gerrit is the first of the six to return. The others are still in France, Algeria, Ivory Coast and the southern Sahara region, Nos said. The birds all have fixed habitats in the Netherlands. Gerrit lives near Kinderdijk in Zuid-Holland province.