MIGRATION* 283 



choose for a rallying 1 point and place of departure 

 those spots whence the passage from the sea to the 

 lakes and rivers is shortest and less occupied by the 

 land. Thus the flocks that assemble in the environs 

 of Genoa and Savona repair first to the banks of the 

 Po ; then following the passes of the great valley of 

 the Alps, which descend into Piedmont, they rise 

 above the mountains, where different species of the 

 birds in question are annually killed. From these 

 points they appear lo direct their flight to the great 

 lakes of Switzerland, particularly that of Geneva, 

 which all the water and marsh birds of Europe 

 resort to for a short period, or pass more or less 

 regularly. From thence they seem to continue their 

 journey by the lakes of Morat, Neufchatel, and 

 Bienne, and repair to the Rhine, by following the 

 course of which they arrive at the Baltic, the great 

 inland seas, and the North Sea. These companies, 

 already less numerous when they arrive in the north, 

 disperse soon after, and make preparations for rear- 

 ing their progeny. 



" The route most frequented by all the water birds 

 is along the borders of the sea. Those which come 

 from the Gulf of Gascony, from Spain, and the coast 

 of Barbary, appear to follow that only. Several 

 species of waders uniformly follow it, and the same 

 route is taken by all those birds which are unpro- 

 vided with powerful means of flight. The divers, 

 the grebes, and other fresh-water fowl, which seldom 

 fly when occupied in the north with the cares of 

 pairing* and breeding, are however endowed with 

 great powers for this action ; their flight is vigorous 

 and long sustained ; they even rise above the high 

 mountains, for it is not rare to find individuals of 

 these species on the lakes of the Alps, where the 

 waders and web-footed species are often killed. 



" It appears that the great flocks which assemble 



