94 COLOR AND CONCEALMENT 
prey or by their enemies. Or, as Gerald Thayer puts it: the object’s 
“obliteratively-shaded surface must bear a picture of such background 
as would be seen through it, if it were transparent.” (l.c. p. 31.) Thus 
our Woodcock is said to bear a picture of “dead leaves, twigs and 
grasses, variously disposed over shadow-holes,’”’ while the plumage of 
Wilson’s Snipe represents “sticks, grasses, etc., with their shadows at 
various distances.” The plumage of the Upland Plover shows a “‘grass”’ 
pattern, a type common to many field or upland species. Certain of 
the Plover and Sandpipers wear this plumage during the summer, when 
they live among weeds and grasses, but lose it for one of pure and 
simple counter-shading when they winter along the shores and beaches. 
From these more obvious instances of obliterative picture patterns, 
Thayer leads us to an interpretation of the brilliantly colored and in- 
tricately marked plumage of birds like the male Wood Duck, Peacock, 
and Paradise Bird (Paradisea), or of such special markings and appen- 
dages as the speculum in Ducks, gorget in Hummingbirds, tail-coverts 
in the Resplendent Trogon, etc., all of which, under certain vital con- 
ditions, are considered by him to make or to aid in making their wearers 
inconspicuous. The use of no pattern, mark or appendage is left un- 
explained by the proposer of this law, and while naturalists recognize 
the importance of his studies, Thayer’s contention “that patterns and 
utmost contrasts of color (not to speak of appendages) of animals make 
wholly for their ‘obliteration,’ ” finds few supporters. 
Flamingoes, Crows, Ravens and Turkey Vultures, for example, 
are seemingly from any point of view conspicuous. The nature of their 
food and their excessive wariness or absence of foes apparently re- 
move them from the action of the laws producing a true concealing 
coloration. 
Protected primarily by the character of their haunts, it is not 
improbable that the striking and endlessly varied colors of Tanagers, 
Honey Creepers, Cotingas, Toucans, Trogons, Parrots and other bril- 
liantly marked arboreal birds may be explained in a similar manner. 
It is important to remember in this connection that many birds of such 
habits are dull as well as brightly colored, and we may suggest that 
among tree-haunting, and to a less extent thicket-haunting birds, the 
actual physical causes of color, uncontrolled by natural selection, have 
run riot. When, however, the nature of a bird’s haunts affords it less 
adequate means of concealment, then color plays a more important 
part in protecting it, and there is consequently less variation from the 
type of color which presumably has proved to have the highest conceal- 
ing value. 
Thrushes, Ovenbirds and Doves, for example, which feed on the 
ground, may frequent the tree-tops without unduly exposing themselves 
to danger, but let a male Scarlet Tanager or other brightly-colored 
arboreal bird alight upon the ground and, even when motionless, it 
is conspicuous. p 
This illustration may serve also to remind us that the protective 
