The British bird book

MY object in the following pages is merely to give a very brief account of some of those birds which are useful, or the reverse, to farmers and gardeners. It is seldom possible, of course, to give an exact estimate of their value. In many cases they are useful in some ways, but mischievous in others. But it must be remembered that while the damage which they do is generally evident enough, their services are very easily overlooked. It should also be noted that, while a gooseberry stolen or a grain of com devoured is a gooseberry or a grain of com lost, and no more, an insect devoured would probably have been the progenitor of a very large number of grubs or caterpillars.
Not more than two or three of our birds are wholly injurious; many are entirely beneficial. And most of the remainder, if not neutral, do a great deal more good than harm.
Theodore Wood (The Author)