478 BULLETIN 17 9, UNITED STATES NATIONAL MUSEUM 



pretentious nuptial song." In Baird, Brewer, and Ridgway (1905) 

 the song is described as "an unmusical creak, rather than a twitter, 

 frequent rather than loud, and occasionally harsh, yet so earnest and 

 genial in its expression that in effect is far from being unpleasant," 

 In an unpublished manuscript S. S. Dickey states: "These sounds 

 are less pronounced and are evener in their outflow than are the 

 sharper ones of the barn swallow. There is not so much metallic 

 'squeak' in their quality as that of the tree swallow." 



Enemies. — The most serious enemy of the cliff swallow, especially 

 of those nesting on barns and other buildings, is the English sparrow. 

 The ousting of cliff swallows from their nests by English sparrows 

 and their importance as a factor in the local fluctuations of the number 

 of these swallows have been a subject of comment by scores of ob- 

 servers of which the following are typical : 



Brewster (1906) states "the Eave Swallow suffers directly and very 

 seriously from the encroacliments of the House Sparrows who destroj^ 

 its eggs and young and take possession of its nests whenever op- 

 portunity offers." Barrows writes as follows : "About the larger cities 

 and towns in Michigan the English Sparrow has been a potent factor 

 in reducing the numbers of Cliff Swallows. The mud nests of 

 swallows form convenient receptacles for the eggs of Sparrows and 

 they often take possession of the nests and drive the swallows away 

 entirely." Forbush (1929) writes: "Thus the 'Cliff' Swallows under 

 man's protection became 'Eaves' Swallows and waxed fat and numer- 

 ous until the decade beginning in 1870, when the House Sparrow 

 began to increase and spread over New England. Then the nests 

 built by the industrious Cliff Swallows were appropriated, after a 

 struggle, by the swarming and ubiquitous Sparrows, whose clumsy 

 and bustling occupancy soon resulted in the destruction of their 

 stolen domiciles. As the Sparrows increased in southern New Eng- 

 land, they spread northward and eastward until the greater part 

 of the Cliff Swallows had been driven into Maine." In Maine, where 

 I have had an opportunity to observe many nesting colonies, there 

 has been but little evidence of the molestation by English sparrows. 

 It is becoming more and more apparent that, as the English sparrow 

 population decreases, the cliff swallows are again becoming established 

 where formerly they were ousted by the marauders. In the far 

 West the English sparrow still remains a menace of increasing 

 importance. 



Grinnell (1937) gives a very interesting account of the invasion 

 of the English sparrows into a large colony of cliff swallows that 

 built their nests on the concrete walls of the Life Sciences Building 

 at Berkeley, Calif. This building, completed in 1929 was first occu- 



