DO BIRDS KNOW THEIR OWN EGGS?

Colonist, Volume LVI, Issue 13489, 8 June 1914, Page 7

DO BIRDS KNOW THEIR OWN EGGS?

Some light may be thrown- on this question by the behaviour of a chaffinch that was kept under observation by a friend who has an orchard in the Valley of the Clyde. In the nest of a willow warbler, which was built, as usual, on the ground, writes Charles Reid, in "Country Life," an egg of the cuckoo had been deposited. As the bird forsook the nest, the cuckoo egg was transferred to a nest of the chaffinch until such time as a suitable nest of a soft-billed bird could be found in the orchard. In order to allay suspicion on the part of the birds one of their own eggs was removed at the same time. At, last a nest of the hedge-sparrow was discovered in a safe retreat, but when my friend went to fetch the precious egg it had gone, while the other three were left. \

My friend hit on a plan to ascertain whether the chaffinches themselves were not to blame. He took a deserted robin's egg and placed it in the nest of the sitting1 bird. On the following morning it also had disappeared. He .was now almost certain that these removals were effected by the chaffinches. Another egg of the robin, this time coloured to resemble that of the cuckoo was inserted. On this occasion ho retired to a distance, where provided with a field-glass, he had a good view of the nest, on which he kept his eye during the absence of the female. The latter had not been long gone when the male appeared, and soon after took her place. Unlike his mate, that sat close, he fidgeted about a good part of the time, but never quite left the nest till she returned, when lie at once flew away to a considerable distance.

Before the female had time to approach the nest niy friend hurried forward to find his worst suspicions confirmed. In the absence of the female the male bird had, without a doubt, removed the strange egg. Besides it must have been carried a distance, as, after the most careful search, no trace of it could be found in or about the nest or within twenty yards of the tree.