This section is from the book "The Balance Of Nature And Modern Conditions Of Cultivation", by George Abbey. Also available from Amazon: The Balance Of Nature And Modern Conditions Of Cultivation.
Although birds range over a much wider area than four-footed animals, they are mostly restricted to certain limits of country, food being the all-important factor combined with convenient places for refuge and breeding in the immediate location. This applies to the resident denizens of the woods, fields, and other tracts of country peculiarly suited to the respective species, which, beyond separating for nesting, are not given to leave their domiciles for other purposes than the procuring of food and exercise of their bodily powers. But birds, like everything in nature, are given to change of location through the interference of man with their natural requirements and adaptations, and while some possess facilities for conforming to the new order of things, a number of species are not so fitted for what may be termed cultured necessities, and hence are obliged to leave and find out, if possible, suitable quarters for continuance of existence. These are matters the cultivator is apt to overlook, the changed state of nature in bringing land into cultivation inducing a new order of affairs in respect of bird-life in the location.