54 SPRING 



March. Its nest is a very warm and solid one, plentifully 

 lined with locks of wool, instead of the grass-tufts and 

 dry leaves used by the rook. Jackdaws nest about the same 

 time as crows, in the middle of April, though their choice of 

 holes instead of open trees might seem to warrant them in 

 beginning earlier. The general rule that the darkest eggs 

 are laid in the most exposed sites is well illustrated in 

 this family of birds. Rooks and crows build open nests in 

 the tree-tops, and their eggs are the darkest of the group, 

 though pale varieties are not uncommon. The magpie's 

 nest has a light roof of sticks, and the average colour of its 

 eggs is considerably paler. Jackdaws nest in holes in rocks, 

 buildings and trees, and their eggs are paler still. They 

 betray, however, their connection with a family which chiefly 

 haunts trees by being heavily spotted, instead of being pure 

 white like those of owls and kingfishers and other typical 

 hole-nesting birds. This seems to show that their habit of 

 nesting in holes is a comparatively recent one ; their eggs 

 have not yet lost completely the dappled markings which 

 were developed in open nests. A similar example is that of 

 the puffin's eggs, which are laid in crevices and burrows, but 

 retain faint spots or faded serpentine lines denoting their 

 kinship with the razorbill and guillemot family, the other 

 members of which lay their eggs on open ledges. Just 

 as hawks' eggs are usually ruddy, and gulls' eggs olive or 

 brown, all the members of the crow family lay eggs of some 

 tint of green. A nestful of deep green crow's eggs forms a 

 beautiful harmony of colour with the overhanging needles in 

 the crown of a fir ; and the theory of protective assimilation 

 is on the whole borne out by the distinctly brownish shade 

 of most rooks' eggs, which lie on a cushion of dead grass or 

 withered leaves. 



The pale olive-brown of the pheasant's eggs shows no 



