112 THE COMPLETE WILDFOWLER 
by the weather. Of course, brent occur every year, but for 
great numbers to visit us we are much dependent on the severity 
of the winter on the Continent. The severity of our winters 
counts as little on this score, except that when hard the fowl 
are not so difficult to procure.. Bernacle, although allied to 
brent, more closely resemble the grey geese in their migratory 
movements. Being marsh-feeders, bernacle geese frequent very 
local areas in our islands. ‘The bernacle has frequently been 
shot in August. At this season they have been met with at 
places which are not usually visited by them. As this fowl 
is fairly common as an ornamental waterfowl, it may be 
possible that these early visitors are ‘‘ escapes.” 
In spring a return of the fowl and shore-birds takes place. 
The majority of the wildfowl leave us first. The shore-birds 
which have wintered further south, such as the whimbrel and 
curlew-sandpiper, pass our shores in May. A few linger 
until the first week in June. All the summer a few straggling 
shore-birds may be seen on the coast, including godwits, 
turnstones, grey plover, sanderlings, and knots. These may 
be immatures which have not gone on to breed, or possibly 
they are either barren or ‘‘ pricked ” birds. 
The fact that birds which nest with us but move south in 
autumn, while others of the species from the north taking their 
place, touches the question of migration pure and simple, serv- 
ing well to illustrate the theory that food and cold do not at 
present influence the migration of birds, as many suppose. 
Migration of birds is caused by something more than the 
immediate necessity and demand for food, although in the ages 
past this has played an important part in bringing about the 
habit. We have many mysterious little points touching migra- 
tion which might be discussed at length to advantage, but to 
which it is impossible to refer more than briefly, such as the 
fact that many species after enduring long migratory journeys 
will starve to death sooner than go further south. I cite the 
