Page:The Zoologist, 4th series, vol 3 (1899).djvu/198

172 is necessary to remember that such nests are nearly always partially covered by overhanging leaves and branches, by a projection of rock or stone, by thick herbage, or by sedges and long grasses. This fact will often account for the deeper or paler shades of egg-colouring.

I. Eggs laid in open nests are coloured.

(a) The ground colour of those laid in trees and bushes is often some shade of green or blue marked with brown, red, or black, e.g. Thrushes, Finches, Crows.

(b) When the nest is placed very low down amongst herbage, or when it is placed in a covered site, the ground colour of the eggs is paler, and so are the markings, which are sometimes greenish, e.g. Redbreast, Wagtail, Whitethroat; but not so the Pipits.

(c) When exposed to some extent on the ground they are generally clay-colour, or brown, or greenish brown, spotted and blotched with a darker shade, or even with black, e.g. the Lark, Lapwing, Curlew, Gulls.

(d) Certain birds, as Ducks, Partridge, Grebes, cover their eggs when they leave the nest. Such eggs are usually white or of a pale tint. This might be expected, as the protection of colour is in such cases unnecessary.

(e) Large birds which are able to defend themselves may be expected to be capable of keeping their eggs safe from the attacks of Crows, &c. Swans and Cormorants will come under this head.

II. Birds which nest in holes nearly always have white eggs, e.g. Swift, Woodpecker, Kingfisher, Puffin, Petrel. But very small birds so nesting generally lay white eggs speckled with red.

The only exceptions which occur to me are the Wheatear, Redstart, Starling, Jackdaw, and Chough. The first two of these have already been dealt with. I have no personal knowledge of the Chough. But there is some reason to suppose that nesting in holes is a comparatively recent habit both with the Starling and the Jackdaw. In 1887 I found two Starlings' nests which were "open." One was at the top of a spruce-fir, built upon an old Wood-Pigeon's nest; the other was in ivy. Perfectly fresh-laid Starlings' eggs differ very much, varying from a decided blue to nearly white. Jackdaws sometimes lay their eggs in hollow trunks, where they can be seen from above.