XXIV INTRODUCTION. 
tints with which so many birds’ eggs are now adorned. In most birds 
where 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 Rollers, 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 les 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 still 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 
