234 ELEMENTS OF ORNITHOLOGY, : 
The extreme punctuality of Birds in their migrations is often 
very remarkable. This is especially the case with Water Birds. 
Whatever may be the weather, the Puffin has been noted as 
arriving on the very day it was, from previous experience, 
anticipated. 
The motive of the return northwards is more mysterious 
than the impulse which drives Birds south. The latter may be 
explicable by growing scarcity of food. The former can as 
yet be only regarded as the result of an instinctive longing to 
return to a wonted haunt. The accuracy and perseverance of 
this return has often been observed, but never better than by 
Professor Newton. He tells * us: “ A pair of Stone-Curlews 
(Hdicnemus ecrepitans)—a very migratory species, affecting 
almost exclusively the most open country—were in the habit 
of breeding for many years on the same spot though its 
character had undergone a complete change. It had been part 
of an extensive and barren rabbit-warren, and was become the 
centre of a large and flourishing plantation.” 
It appears that migrating birds often pass along the coasts 
of countries which We in fier line of march. Ts it is said + 
that some skirt the west coast of Norway as they pass from 
Siberia to us. River-courses are also preferentially followed. 
Others leave Northern Russia, skirt the Gulf of Finland to 
Holland, then pass by the V alleys of the Rhine, and along the 
coasts of France and Spain, to Africa. 
The way in which migration is accomplished remains still 
unexplained. It has been said to be due to past ‘ experience ” 
of landmarks, but how can that guide birds in their first year 
that do not migrate in companies? How can it account for the 
ereat distances of sea which are so often successfully traversed ? 
There are some Birds which migrate irregularly, as do the 
Crossbills, Nutcrackers, and Waxwings. Sometimes birds from 
distant regions make their appearance in strange localities, as 
do, ¢.g., American birds in Norfolk and Suffolk. Sometimes, 
also, 2 migration takes place comparable with the invasion of 
Europe by the Huns. Such an example we have in Pallas’s 
Sand-grouse, which before 1863 was only known as an inhabitant 
of the plains of Tartary, but which has now come to establish 
itself in Europe and once at least actually bred in England. 
* Ency. Brit., Article “ Birds,” p. 766. 
+t See Palmén’s ‘Om Fylarnes flyttingsvagar’ (Helsingfors, 1874). 
