NORTHERN CLIFF SWALLOW 467 



in migration. The birds rested for a time in the same grove of dead 

 pines where large numbers of tree swallows had been observed. 

 Knight (1905) describes an interesting observation he made of fa- 

 tigued migrating cliff swallows at Bangor, Maine, on May 17. "They 

 were perched by hundreds in low shrubs and bushes between the 

 Bicycle Path and a flooded meadow just beyond. Some small wil- 

 low bushes were each occupied by fifty or more Swallows, whose 

 drooping, half-spread wings and open beaks, through which they 

 drew spasmodic gasps of air, were a most eloquent testimonial of the 

 fact they had just arrived from a long journey and were exceedingly 

 fatigued." 



The route of migration takes the cliff swallow over thousands of 

 arduous miles of travel, but nevertheless their arrival is remarkably 

 punctual, sometimes varying but a day or two from the expected time, 

 a fact readily verified by any one who observes the appearance of the 

 birds at the nesting colonies. The arrival of the cliff swallows at the 

 colony located on the walls and arches of the old San Juan Capistrano 

 Mission in southern California has been given great publicity and in 

 recent years has even been the subject of radio broadcasts. It has 

 been claimed that the birds never vai^y from March 19 ; even the hour 

 of their arrival has been said to be constant. Ornithologists who 

 have checked these assumptions have found that the swallows are not 

 infallible to such extravagant claims. 



Courtship. — The courtship of cliff swallows is carried on simul- 

 taneously with their early nesting activities and especially in places 

 where the birds are busily engaged in gathering the mud used in the 

 construction of their homes. The two following accounts of obser- 

 vations made in widely separated sections of the country will serve 

 to illustrate their interesting behavior at such times. Brewster (1938) 

 in his journal of the birds of the Umbagog region vividly describes the 

 activities of cliff swallows he obsen'ed in that retreat on June 8, 1909, 

 as follows : 



This morning as I was watching the birds I saw two come together in the air 

 and whirl around and around straight down to the ground, where they remained 

 for more than a minute, in what I took to be sexual union, waving and fluttering 

 their wings like butterflies. The other members of the colony seemed actively 

 interested in the affair, and, indeed not a little excited about it, for they 

 collected over the prostrate birds and dashed dowTi almost to them, with loud 

 cries. When the pair finally separated, one bird tlew off in one direction and 

 the other in another. I do not think it could have been a fight, for Eave Swal- 

 lows are among the most peaceable and social of all birds and I have never 

 known them to show the slightest tendency to quarrel. 



Wetmore (1920) describes the activities of cliff swallows he 

 observed in New Mexico as follows : 



On June 11 they were building nests on the sandstone cliff above the Laguna 

 de la Puerta. The birds came down to the lake shore in little bands of ten 



