Page:The Zoologist, 4th series, vol 3 (1899).djvu/578

548 usually does." Mr. Wallace considers that these eggs "are coloured in a specially protective manner," but it is equally open to argument, that as white eggs are concealed, and the mottled-grey egg of the Nightjar laid on the similarly coloured ground, so the concealing, or active mimicking, powers of the Coot suggest its placing its eggs among the leaves that so successfully hides them.

That birds may use a reasoning or cunning attribute in the deposition of their eggs where the colouration may prove of an assimilative character to the surrounding environment may be argued from the evidence which exists of their pursuing an equivalent mental process in the placing of their nests. Thus recently a writer has described "some curious experiences in birds' nesting." He found a Blackbird's nest "situated in a depression in the ground, in just such a position as a Sky Lark's might occupy." A keeper who accompanied him had found several other Blackbirds' nests in similar positions. Within a few hundred yards two Thrushes' nests were also found on the ground, "the edge of the nests being level with the surface." On enquiry it was stated "that the proprietor, having found that this wood was a nesting stronghold of these species, had made systematic raids on their nests in consequence of the havoc made by the birds on his fruit. I think this fact suggests why these birds had departed from their usual habit in their choice of nesting sites. Profiting from experience, they had selected safer positions." The same writer records facts to prove that the Common Sandpiper "profits by experience, and occasionally varies its choice of nesting sites." In 1886 these birds had their nests twice swept away from the river-banks by heavy floods. In the following year nests were found fully a hundred yards from the river. "From May, 1886 (the date of these floods), until 1889, the Sandpipers continued to nest at some distance from the river." The Sumoan Tooth-billed Pigeon (Didunculus strigirostris), which formerly bred on or near the ground, and was so greatly reduced in numbers by Cats as to be threatened with extermination, eventually took to nesting and roosting in trees, and has since been gradually on the increase." We have not