We learn from this that when we find that one region, be it large or small, is unlike every other region in some particulars of climate or vegetation or temperature, or when it is not easily accessible from other regions, we may expect to find the animals somewhat different according to the conditions which prevail. From this it is a clear step to the truth that an animal’s environment exerts a considerable influence upon its life and through its life upon its form; changing the form in some particulars that make it different from all other animals. It is also true of plants. Since, then, there are different physical conditions in every country of any considerable size, these changes in plants and animals are going on now, but so slowly that we are not able to see them. At the end of another thousand years or longer, the species of birds which we now know may be so changed that we should not know them if we could see them. But that need not worry us! Lynds Jones. [Illustration: ] THE HOODED WARBLER (_Sylvania mitrata._) “He was recognizable at once by the bright yellow hood he wore, bordered all around with deep black. A bright, flitting blossom of the bird world!”—_Leander S. Keyser, in Bird Land._ This beautiful little warbler is a resident of the eastern United States. It is more common in the southern portion of this district and throughout the Mississippi Valley. Its breeding range extends from the Gulf of Mexico as far to the northward as southern Michigan. It winters in the West Indies, in Mexico, and in Central America. Though a wood warbler it prefers the shrubby growths in low and well-watered places rather than the forest. It is said to be abundant among the canes of the Southern States. Many other names have been given this warbler, all having reference to the arrangement of the black and yellow colors on the head. It is called the Black-headed Warbler, the Hooded Flycatching Warbler, the Mitred Warbler, and the Black-cap Warbler. Activity seems to be the keynote of its life. It is in constant pursuit of insects, which it catches while they are on the wing. Unlike the flycatchers it seldom returns to the same perch from which it flew to catch its prey.