buds. (See Plate VI again.) Except when a wet snowstorm or an icestorm 

 has plastered and veiled these twigs, the average northern landscape in win- 

 ter is full of great masses of soft, purplish red, reaching here and there a 

 brighter tint. Golden brown, varying to red and purple, is also the color of 

 the cones of spruce and pine and fir trees. It is among these pink and bronzy 

 twigs and buds, seed tassels and cones, that the northern grosbeaks, linnets, 

 and crossbills get their food, and the red or reddish colors worn by many of 

 them are therefore in full accord with their environment. So it is also that 

 the red spots on the heads of the males of northern woodpeckers are not dis- 

 cordant notes in their obliterative pattern. 



Female crossbills and pine grosbeaks are olive-green, olive-yellow and 

 gray — the colors of tree trunks and the foliage of evergreen conifers, and 

 many of the cones themselves. 



The coloration of some of these birds, notably the Red Crossbills, some- 

 times helps to produce a truly mimetic effect. In conformity with their acro- 

 batic habits of topsy-turvy climbing and feeding, these crossbills have a very 

 scant obliterative shading. In a full, unbroken light their solidity is therefore 

 apt to show, and when they sit or cling on coniferous trees they often look 

 much like cones, by virtue of their similar colors and not dissimilar shape. 



Once more we must return to the subject of obliterative white markings 

 on birds' upper sides. The birds that wear them may be grouped as follows: 

 those that live high enough up in trees or bushes so that glints of sky and 

 gleaming foliage- vistas are common factors of their background; those that 

 live on the water or the borders of water, where reflected glints of sky are com- 

 mon; and, last but not least, those which live amid snow. Predatory birds 

 that are mainly white all over, like many sea birds and the Snowy Owl, are, 

 as we have shown, equipped for the greatest possible elusiveness when seen 

 against the luminous sky by animals beneath them. The application of this 

 principle among mammals we shall describe in a later chapter. Its bearing 

 on the coloration of birds alone is large, far larger than one would at first 

 suppose. It is involved, for instance, in such cases as those of the snow- 



117 



