I1I2 THAYER, Banner Mark Theory. rea 
while a plain black or white wing, or one with any kind of strong 
pattern on an empty ground, would serve to distinguish it far 
better, in the woods? On the other hand, while Gulls have 
pretty good “banner marks” on their primaries, they miss a 
great opportunity for immensely greater self-differentiation in 
powerful under-wing patterns, and if my theory be correct, this 
they are prevented from having by the greater importance of coalt- 
tion in appearance with their blank ocean and cloud back-grounds. 
In short, both the barred wings of wood-dwelling Raptores and 
the unmarked wings of ocean birds confirm the impression that 
nature finds it worth while to paint on most animals an imitation 
of their normal background, even when, as in the case of the 
under sides of wings, and where such under-sides are habitually 
exposed to view, there would seem to be small use in it, and her 
finding this worth while, suggests that we have still much to learn 
about their home habits. 
It is also significant that among our native Raptores, for 
instance, the three species that wear on their under wings the 
least amount of cross-barring are those that spend the most of 
their time out of the woods in fields and marshes. ‘They are the 
Marsh Hawk, Rough-leg and Short-eared Owl. 
The deep-wood-dwelling Long-ear has the Short-ear’s wing 
with some forest pattern added. Mr. Thompson in his plate of 
under patterns has wholly omitted the Goshawk’s cross-bars, 
which are like those of the two smaller Accipiters, only fainter. 
He has also given the Red-shoulder much too strong under-tail 
bars. Otherwise his diagrams are pretty just, only they give an 
impression that these patterns are far more visible at a distance 
than is the case. 
I am far from denying that every visible distinction Ze/ps recog- 
nition (though I believe that the uses of the recognition are still 
very hazily conceived), and have mainly attempted to show what 
other forces are at work upon animals’ colors. Unmistakably, 
nature regards concealment, both of the hunter and hunted, as of 
paramount importance. 
One other point: Granting that these under wing  barrings 
make, mainly by their different degrees of local darkness, etc. 
different patterns, at a distance, at least in different genera, 
