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 THE. CO.BO.R Volume Xll March-April 1910 Number THE EFFECT OF NATURAL ENEMIES ON THE NESTING HABITS OF SOME BRITISH HONDURAS BIRDS By MORTON E. PECK WITH FOUR PHOTOS BY THE AUTHOR URING some two y, ears of scientific investigation in British Honduras, the writer had occasion to study somewhat the nesting habits of the birds of that region, and was strongly imprest as any observer might well be, by the great variety and ingenuity of the devices employed evidently to baffle the attacks of natural enemies. Considering the great abundance of food, the absence of de- structive storm.s, and other obviously favorable conditions, we might expect the birds'of that section to be correspondingly plentiful; nevertheless, while species are sufficiently numerous, individuals are much less so than in most temperate regions where the numbers have not diminisht thru the operation of artificial agencies. Taking these facts into account, we must conclude that enemies are far more abundant and destructive in the tropics than in hiher latitudes, and that the struggle for existence is even sharper, tho of a somewhat different nature. Let us consider the subject more in detail. It would be but a moderate estimate to say that thru two seasons of observation by the writer one-half of the nests found while being built were robbed by natural enemies before the incubation period was half over. These enemies may be divided into four classes: first, predatory birds, which comprise a comparatively. large proportion of the avian fauna; second, reptiles, of which species and individuals are extremely numerous; third, small mammals, of perhaps a dozen species; fourth, insects, especially several species of ants. These four classes differ greatly in de- gree of importance, the reptiles--snakes and lizards--being probably the most de- structive. As regards their structure and location, the nests of birds may be placed under four groups as follows: First, open above and supported from beneath,. on the ground, in grass-tufts, bushes or trees; second, in cavities of trees, rocks or banks; third, open above and pendant from a horizontal branch or leaf tip; fourth, roofed