The grey goose "Anser joerpical" is a near related species of the common grey goose anser anser.
The Anser joerpical lives in western Archanta. The habitat are the wide tidal land around the Jørpenilands. Here the birds live in the summer in great colonies at the grass near the tidal land and breed there in the longer summer days at 48° south.
The bird watching station at the Jørpenilands meanwhile has ringed over one million of this birds. So the ways of them around the seasons since 1900 are relative clear. But 2001 the first birds have small transponders around the ringed feet and so theyr way are known with more details and knowledge.
Now is known an interessant cyclus of flying between the seasons. One of the first birds with this transponder was the gander "Oscar", breeded 2001. Clear is, that in the first year the young goose fly with older leading gooses only the shorter way over land to the Drull-delta. Here most of the young goose choose their partner. As other goose with this partner they normally live together a lifetime. Oscars partner was "Lissy", ringed as Jø 837,529 and still living with him. So the partners are always at the same age.
In the winter the birds fly back to the Jørpenilands and breed the first time. In the second summer they then fly to the Pladde Sii in Zylanda over the land over Mercyna. Most of them fly this way one or two years. Only few pairs of goose fly this route more years.
Older and strong birds then take the red route over the sea, which is shorter (red route on the map). So the gander "Oscar" with "Lissy" this short route fly first in the year 2004. This birds earlyer arrive the better places for the winter quartier as this birds, who fly over Mecyna (blue route) and the better breeding-places at the Jørpenilands, because they are the first, which arrives.
Older birds then take again the blue route (so as "Oscar" and "Lissy" 2011 and 2012) or fly with the young goose the short route to Drull ("Oscar" did this 2013 and 2014).
If a gander is not more able, to fly the red route, but the goose is it, she sometimes will choose an other gander - or vice versa. So the choose of the route is a question of survival of the fitter genes. Often - so the biologist have mentioned - both (gander and goose) together then fly again the blue route or the Drull-route with the new goose, if there are older.