“THE IRREGULAR MIGRATIONS OF BIRDS. 389 
about themselves; on suitable occasions they picket out their ? 
dogs over night, to procure the cross, with constant success. What 
profitable quality is secured, I do not know; but such is the case. 
These crosses are not known to be otherwise than fertile; and the 
result is, in every Indian community there are mongrel dogs shad- 
ing into coyotés in every degree; all having the clear wolf strain, 
and some being scarcely distinguishable from a prairie wolf. 
The matter of color merits passing mention. The coyoté is as 
constant in this respect as other ferze, and I think its peculiar col- 
oring can be reasonably traced in certain dogs. The animal is 
dingy white as a ground color, which remains so on all the under 
parts; above it is suffused with tawny-brown (bright in summer, 
paler and more grayish, or quite gray, in winter), this color over- 
laid with a clouding of black. This black is rarely uniformly dis- 
tributed; it tends to streakiness along the back and across the 
shoulders and hips, producing a pattern similar to that of a ‘“brin- 
dled” bull-dog. But there is a more striking feature, and one very 
characteristic of the animal (the brindled gray and black being 
shared exactly by an ordinary strain of C. lupus). The top of the 
muzzle, back of the ears, and outside of both fore and hind legs, 
are usually nearly uniformly tawny. This shade is precisely the 
so-called “tan” of the black-and-tan terrier, and has the same 
general distribution. In an attempt to trace pedigree, a fact of 
this sort seems to rank in value with the sii ao ina horse or 
mule, of the stripes of a quagga-stock. 
THE IRREGULAR MIGRATIONS OF BIRDS. 
BY T: MARTIN TRIPPE. 
edits 
Tae annual migration of birds ; their moving north and south in 
` the spring and autumn, is obvious enough to every one. In its 
_ Various phases it is well discussed in various ornithological works, 
a is pretty thoroughly understood, comparatively speaking at 
. But in addition to their vernal and autumnal changes of 
habitat, movements occasionally take place among birds not de- 
7 — the seasons; invasions as it were of certain prov- 
