Nature's First Law 



they concealed while yet completely exposed. 

 Young terns, when running about the beach for 

 food, stop short the instant danger threatens and 

 keep still instinctively their colouring usually 

 affords all the protection necessary. 



Every sportsman knows how wary the wood- 

 cock is, yet so confidently does the hen rely on the 

 mimicry of plumage amid the dry leaves and fallen 

 logs around her, that one can place a camera 

 squarely in front of her ground nest and photograph 

 her on it without causing her concern enough to 

 wink an eyelid. There was no need for birds so 

 protected to build in trees. Seated among last year's 

 leaves, the brown ruffed grouse feels sure, as well 

 she may, that you can scarcely distinguish her from 

 them. When danger threatens her chicks, the 

 youngest downy ball knows enough to stand or squat 

 motionless, while the mother, by feigning lameness 

 or a broken wing, tries to decoy you away. Stand- 

 ing even in the midst of a surprised covey of young 

 grouse, who is clever enough to count them all ? 



EVERY FEATHER MEANS SOMETHING 



The most casual observer must have noticed 

 that many birds are dark above and lighter under- 

 neath, like the cuckoos, vireos, flycatchers, and 

 sparrows, to mention only a few groups. Of what 

 bird, indeed, is the reverse true? This colouring, 

 of course, accords with a law of optics whereby 

 dark upper parts receiving the most light appear no 

 darker when seen from a distance than pale under 

 parts which receive less direct light. The result, 



