BREEDING HABITS OF THE SWIFT. 287 



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 Star- 

 lings 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 Cypselidcs. 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. 0. 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. 656) 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 



