Page:The Zoologist, 4th series, vol 5 (1901).djvu/314

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a widely distributed bird, Cypselus apus is difficult to observe at nesting-time, on account of the inaccessibleness of its usual breeding-places. Presumably this is the reason for the uncertainty which exists with regard to one or two points in its history.

The Swift is one of the most regular of our migratory birds, and is usually first seen in this county between May 2nd and 5th. Mr. Storrs Fox has seen one at Bakewell as early as May 1st, but May 4th may be taken as the average date, and it is not at all uncommon for them to arrive exactly on that day. Although they resort to the nest-holes before that time, eggs are seldom found before the last days of May, and about the same numbers seem to return every year. Most nests in this neighbourhood are made under the eaves of lofty buildings or in thatch, but some pairs may be found nesting in the natural crevices of the steep limestone rocks at Dovedale and other places. The Swift can squeeze itself through a remarkably shallow opening, barely wide enough to admit the fingers, and the nests are usually some little way from the entrance. Where suitable sites are available, they seem to prefer to breed in company, but a single pair may often be found nesting at some distance from any colony. For over thirty years a colony of seven to eight pairs has nested under the eaves of a house in this neighbourhood, which stands by itself on a hillside, and offers unusual facilities for observation.

The first thing that strikes one in watching these Swifts is that they play a regular game. On a summer's evening some five or six birds may be in sight, hawking busily in different directions, when suddenly one will dash off towards the house screaming. Every Swift in sight at once joins in the chase,