xxiv INTRODUCTION. 



tints with whicli so many birds' eggs are now adorned. In most birds 

 wbere the eggs are hid from sight, either in domed nests or in nests in 

 holes, we never find their eggs exhibiting much colouring-matter — it is not 

 required, therefore it is not developed. Eggs brought to maturity in such 

 places are mostly pure white or pale blue, and only in the minority of 

 cases more or less faintly spotted. As instances coming into this 

 particular group we have the eggs of the Woodpeckers, the Kingfishers, 

 the Eollers, Bee-eaters, Tits, Willow-Warblers, Wrens, nearly all the 

 Owls, and the Martins, all of which are pure white or, in some few cases, 

 sparsely spotted, and are laid in covered nests. This law is almost universal, 

 and, curiously enough, white eggs are correlated to a great extent with the 

 brilliant plumage of the bird ; for we have already seen how so many of 

 these showy birds breed in covered nests. Indeed it may almost be laid 

 down as an axiom in oology that brilliant birds do not lay handsome eggs, 

 and most of the finest marked eggs are laid by species of dull and sombre 

 plumage. Every rule, however, has its exceptions ; and we now have to 

 notice 



■White eggs laid in open nests. — If these examples are sufficiently 

 numerous to merit the importance of a separate group, the existence of any 

 laws of colour might be doubted by the casual observer. These instances are 

 both striking and numerous ; but when we come to study and investigate 

 them, we find that they only tend to prove the existence of such laws in 

 a very marked degree. The Ducks all lay spotless eggs, light in colour, 

 greenish white, cream-colour, and pure white, and as they lay in the nest 

 are very conspicuous and readily seen at long distances. The Pheasant 

 and the Partridge also lay eggs of colours not much aiding in their 

 concealment. The Grebes may also be cited as instances. But all 

 these birds possess the singular habit of covering their eggs with materials 

 similar in colour to surrounding objects when they leave their nests. 

 Take, as an instance, the Little Grebe. The nest of this bird is rarely 

 indeed placed far from the water, to which the sitting bird instantly retires 

 on the approach of danger. The eggs of this bird are very conspicuous ; 

 but the moment danger threatens she adroitly covers them over with the 

 materials around ere she glides hurriedly away. So perfect is this decep- 

 tion that the nest is often passed by as a mere mass of reeds and rubbish 

 yet under it lies the treasure she has so cleverly concealed. This little 

 bird is ever on the alert for enemies ; her mate also gives the signal of 

 alarm, and so quickly does she accomplish her purpose that rarely indeed 

 are her eggs seen exposed, except when the full complement is not laid. 

 It has been urged, and several accomplished naturalists are stiU of the 

 opinion, that birds do not cover their eggs for concealment, but for 

 warmth. The Pheasant covers her eggs when she leaves them ; but the 

 Grouse is never known to do so. Now the former bird^s eggs are certainly 



