Page:The Zoologist, 4th series, vol 5 (1901).djvu/315

Rh and the flock race round and round the house, invariably in one direction, passing close to where the nests are, and screaming all the time. The sitting birds squeal in sympathy as the flock dashes past, and, after several complete circuits, the squealing ceases, the flock suddenly disperses, and desultory hawking is resumed, until the signal is again given, and another game is started. Occasionally one sees short chases carried on in the open, but the recognized course is round the house, and the game is repeated time after time on a fine evening. When the birds are laying the eggs often roll out of the nest, especially when Starlings and Sparrows dispute the possession of the holes, and fragments of broken eggs are usually to be found underneath the breeding-place of a colony.

With regard to the number of eggs laid by each hen, there is some difference of opinion. The point is one worth investigation, especially as it has an important bearing upon the question as to the position of the Cypselidæ. Mr. Howard Saunders, in the new edition of his 'Manual,' says:—"The eggs... are two in number, and when more are found in the same nest they may be the produce of two females." In the same strain. Dr. A.G. Butler writes:—"The number of eggs is normally two; four eggs have been found in one nest, but it has yet to be proved that they were the product of the same hen." On the other hand. Prof. Newton, and many other authors, give the number as two to three, and even four. Lord Lilford says "generally three," and Mr. O. Grabham (Zool. 1898, p. 352), who has found three eggs in Swifts' nests often, even in isolated nests, comes to the conclusion that "the evidence is strongly in favour of the hen-bird by no means infrequently laying three eggs." In some interesting notes on the Swift, by Mr. Steele-Elliott (Zool. 1900, p. 479), is an account of a nest which contained three eggs, and was only observed to be visited by one pair of birds. This is confirmed by a note (p. 556) from Mr. A. Bankes, who observed the same thing for two successive years.

In the colony at Ashburne, to which I have already referred, I have often found nests with three eggs, and on one occasion with four: but of course there was no proof that all the eggs were laid by the same bird, except perhaps the similarity of the eggs in each clutch to one another. This year, by first