.318 CHAPTERS ON THE NATURAL HISTORY 



snowy owls might pass as far south as the middle, or even south- 

 central part of the country, whereas the great gray owls would 

 not be found south of the Great Lakes. Exceptional stragglers, 

 of course, violate these laws occasionally, and instances may oc- 

 cur where a bird is taken way off its range, far from its normal 

 habitat, but just why the Swainson warblers in the spring come 

 no further north than southern Virginia, while the Yellow war- 

 blers (IK cestiva) will extend I heir migration at the same time as 

 far north as the fur countries, is something that, as yet, no one 

 has satisfactorily explained. On the Pacific coast, and through- 

 out the great central valley of the Mississippi, the same phenom- 

 ena confront us. Then in nearly all geographical areas there are 

 a few birds that are resident, or never perform ordinarily any 

 migrational passages a1 all. but remain the year round in the 

 land of their birth. We have a great deal to learn in these prem- 

 ises yet; in fad, we have but very little information as to the 

 causes or the origin of facts such as have here been pointed out. 



Now if one, familiar perhaps only with our better known birds, 

 — as robins, jays, flickers, chewinks, and the like, will take the 

 pains some morning at daylight to go into the forests, and along 

 the timber-lined streams, either in the spring or autumn, that 

 person will lie surprised at the host of'various species and sub- 

 species that swarm in the tree-tops and in the undergrowth, the 

 great majority of which average about the size of a chippy spar- 

 row, and are quite unknown to him. If the student undertake to 

 collect these, say in any favorable region in the mid-Atlantic 

 Htates' district, he will soon find, as his collection runs up into 

 the hundreds, that there will be a lonj;' series of the small varie- 

 ties to which I have just made reference. They have a ^reat 

 similarity of form and size; some are exquisitely beautiful in 

 plumage (especially the male in nearly all cases); while, apart 

 from a few individual specific habits, the behavior of all, in their 

 haunts, is nearly the same. < Emitting such species as the kinglets, 

 the 1i1s, wrens, vireos, and. of course, all the fringilline birds, 

 and some of the smaller flycatchers and pewees, we can safely 

 say, in so far as the passerine species go, that the residue of this 

 extensive group belongs to the greal American family Hniotil- 

 tidce, or the Warblers. 



Taken together there are certainly in this country some sixty 

 four or sixty-five species and subspecies of these warblers; and 

 in thus reckoning, the water-thrushes and chats (Slums and Ictc- 



