NIGHTJAR. 
SWIFT. HOUSE-SPARROW. CORN-BUNTING. SWALLOW. WOODPECKER. 
SOME INSTANCES OF COLOUR-PROTECTION 
SKYLARK. 
CUCKOO. 
GREY WAGTAIL. 
IN BIRDS’ EGGS. 
By C. H. Toran. 
O the casual observer the many and varied colours of birds’ eggs 
are meaningless, and do not suggest anything beyond their curious 
beauty; yet probably every one of these varied and numerous shades 
serves a definite purpose in nature, principally as a means of conceal- 
ment from the many enemies to which a bird at this early stage 
of its existence is exposed, in the same way that it 1s protected later 
on in life, when all birds assume such colours, where necessary, as 
may best conceal them from thei still greater army of foes; e.g., as 
a general rule, all our feathered friends that spend the winter with 
us wear dull, dusky, or neutral liveries, so that they escape ready 
discovery while among the bare branches of our deciduous trees, 
which harmonise perfectly with them plumage. If this were not 
the case, hawks and other birds of prey. would work sad havoc 
amone our gentler winter residents. The reason that the wnder- 
surface of the bodies of such birds is lighter m colour than their 
backs 1s very apparent, for little danger threatens them from beneath, 
and the branches themselves offer a natural protection from this 
quarter. 
The principal constitutent of which an egg-shell is composed is 
carbonate of lime (limestone), which in a pure state is a whitish 
substance: thus the interior of the shell of all eggs is white, or 
only slehtly tinted. It is probable that the origmal colour of all 
eges was white (a statement which is confirmed by the fact that 
all birds which lay them eggs im holes or build covered-in nests, 
v.e., those that have retained this habit for some considerable time, 
lay white or pale eggs). 
Of the class of birds which build and deposit their eggs in holes 
may be mentioned the Owls, Woodpeckers, Tree-Creepers, Wryneck, 
Kingfisher, Sandmartin, and Puffin, as well as several other sea-birds ; 
and of the birds which build covered-in nests may be mentioned the 
Dippers, whose eggs are pure white, the Wrens and some Tits, the 
eggs of which are usually spotted with pale colours dispersed over 
a white or pale base, but are frequently pure white or shghtly marked 
with neutral tints. 
