430 MOVEMENTS OF THE CRESCENT SWALLOW 



wick, in 1828. Dr. Brewer received their eggs from Coventry, 

 Vt., in 1837, when they were new to him ; but the date of their 

 appearance there was not determined. They are said by the 

 same writer to have appeared at Jaifrey, N. H., in 1838; ot 

 ^ Carlisle, Pa., in 1841 ; and the appearance of a large colony 

 which he observed at Attleborough, Mass., in 1842, indicated 

 that they had been there for several years. During the last- 

 mentioned year, they were present, apparently for the first 

 time, in Boston and neighboring metastatic foci of the globe. 

 The record also teaches that these birds do not necessarily 

 change from "Cliff" to "Eave" Swallows in the East, for in 

 1861 Professor Yerrill discovered a large colony breeding on 

 limestone cliffs of Anticosti, remote from man, and in their 

 primitive fashion. That the settlement of the country has con- 

 duced to the general dispersion of the birds during the breed- 

 ing season in places that knew them not before is undoubted ; 

 but that any general eastward migration ever occurred, or that 

 there has been in recent times a progressive spread of the 

 birds across successive meridians, is less than doubtful — is 

 almost disproven. Birds that can fly like Swallows, and go 

 from South America to the Arctic Ocean, are not likely to cut 

 around via the Mississippi or the Rocky Mountains, houses or 

 no houses. Moreover, the scarcity or apparent absence of 

 these birds in the Southern States, or most portions thereof, 

 may be simply due to the ineligibility of the country, and only 

 true for a part of the year. It cannot be that the breeding 

 birds of Pennsylvania, New York, and New England come and 

 go by other than a direct route ; and if not detected in the 

 Southern States, it must be because they fly over the country in 

 their migrations, and do not stop to breed. It is authenticated 

 that they nest at least as far south as Washington, D. C, 

 where Drs. Coues and Prentiss found them some twenty years 

 ago to be summer residents, arriving late in April and remain- 

 ing until the middle of September, though they were not as 

 abundant as some of the other Swallows. 



It may be remembered in this connection that a happy con- 

 junction of circumstances is required to satisfy these birds. 

 Not only are cliffs or their substitutes necessary, but these must 

 be situated where clayey mud, possessing some degree of adhe- 

 siveness and plasticity, can be procured. The indication is 

 met at large in the West, along unnumbered streams, where 

 the birds most do congregate; and their very general dispersion 



