The cosmic scheme is one of most intricate interrelation, in which the fact that living things are organized to prey on one another plays a most important part. Man's activities in modifying this scheme produce far-reaching results, generally unforeseen, sometimes disastrous for him. When, for example, we cause the wholesale destruction of harmless snakes we shall find in consequence a vast overproduction of grain-destroying rats and mice, such as are the natural prey of snakes. The brutal and insensate destruction of birds, to take another example, is followed by an incalculable increase in disease-conveying and otherwise pernicious insects.
OUR VANISHING SHORE-BIRDS. JAMA. 2011;305(21):2235. doi:10.1001/jama.2011.660