376 THE STRUCTURE AND LIFE OF BIRDS cuapP. 
Exceptional Migrations. 
The Nutcracker, the Waxwing, the Shorelark, 
Pallas’s Sandgrouse occasionally invade Western 
Europe. The Nutcracker is fond of pine forests, nests 
in Scandinavia, in the Black Forest and the Alps, and 
is not as arule given to wandering. The Waxwing 
breeds in Arctic regions, and has a way of suddenly, 
for unknown reasons, forsaking a favourite breeding- 
ground and moving to another district. Five times 
during this century, in winter time, it has appeared in 
Britain in considerable numbers. The Shorelark’s 
summer home is in Northern Scandinavia, Russia and 
Siberia, In its irregular migrations it sometimes 
reaches our east coast. Pallas’s Sandgrouse lives in 
summer between the Caspian and Lake Baikal, in 
winter moves to Northern China, and there has been 
much speculation as to what caused large hordes to 
sweep westward in 1863 and 1888. The onward roll 
of the living wave from place to place on the Conti- 
nent till at last it reached England excited the 
curiosity of people for whom, as a rule, the doings of 
birds have no interest. But in the absence of any 
facts to help us to explain these weird phenomena, it 
is well to let the reader’s reason or fancy have free 
play without attempting to guide him. 
Stray Wanderers. 
American birds, as I have said, occasionally visit 
England, but no return visits are paid by English 
birds to America. Most of those that come to us are 
