8 The Study of Wild Birds 
easily taken as for example the Sandwich Tern, it is safe to say 
that few birds have ever been exterminated by simply having their 
eggs taken. 
It is where the slaughter of the old birds is made the objective 
that the danger of extermination comes in. Such was the fate of 
the Great Auk and the wingless birds of the Southern Hemisphere. 
But egging like everything else must be conducted on intelligent 
and reasonable lines. 
On this point I venture to assert that I have possibly more 
practical experience than most ornithologists and for the simple 
reason that as this book will show it has chanced that I have 
had opportunities for visiting and re-visiting the same breeding 
stations of certain birds at frequent intervals for over thirty years. 
Briefly, my experiences are that no amount of egging will 
ever drive away birds but that the moment the gun and trap are 
employed to slay the parents, there is grave risk of their 
disappearing altogether from the district. True it is that for a time, 
especially in a wild country like Spain, a bird may find a new mate 
to take the place of its dead consort; but the process cannot 
go on for ever. 
Probably most readers of this book who are not ornithologists 
will be surprised on reading how nests are occupied by the 
same species year after year for an indefinite period, but it 
is the regular custom of the larger and easily recognized species 
such as Eagles and Vultures and it is one very easy of proof. 
In only three instances since 1875 amongst hundreds of nests 
visited and dozens robbed do 1 know of the nesting species dis- 
appearing from localities. Every time this was due to the slaughter 
—not by me—of the parent birds, not to the taking of their 
eggs or young. Most usually when birds’ eggs are taken they 
will soon nest again. I have proved that this is the custom with 
most of the larger Raptores. Even where the second laying is 
