The Audubon Societies 



321 



streaked with butif and rufous, like the dead grasses; Owls are irregularly marked 

 like the rough bark of trees, and Sandpipers and Plovers are specked like the 

 sand of the seashore or streaked like the drift. 



With insects this simulation of color pattern is often carried to the extreme. 

 There are butterflies and moths whose markings imitate exactly the dead leaf 

 or the bark upon which they rest. Furthermore the shape of the wing is 

 often modified to make the simulation more complete. 'Dead leaf butterflies, 

 walking sticks, and measuring worms, are familiar examples of insects in which 



FIND THE COUNTER-SHADED MODEL 



It stands at the right of the uniformly colored one; the insert with white card behind the 



models will help you to find it. The other insert shows how conspicuous the counter-shaded 



model becomes when inverted 



Models made by L. A. Fuertes; photographs by H. D. Reed 



the shape has been modified as well as the color, and this device of nature for 

 giving protection has been called 'mimicry.' If we define mimicry as the simu- 

 lation of shape, as well as color, of animals to their environment, we will find 

 it of rather rare occurrence among birds and never as perfect as with insects. 

 The Screech Owl, with its feathers drawn close and its ear-tufts erect, however, 

 certainly 'mimics' a broken piece of bark, and the Nighthawk, sitting length- 

 wise on a limb, simulates the broken stub of a branch in shape as well as 

 color. The Bittern, standing among the dead cat-tails, with its bill pointing 

 toward the zenith, and the Least Bittern on its nest in the pose shown in the 

 accompanying photograph, are, likewise, examples of mimicry, for they 

 resemble in shape, as well as in color, a projecting snag or a broken reed. 



In the plumages of certain birds that are normally very difficult to see when 

 at rest, we find a very different color pattern which seems at variance with all 



