186 LIFE HISTOEIES OP NOETH AMBEIOAN BIEDS. 



strange as these States abound in suitable cliffs, and tlie White-throated Swift 

 ajDjDears to be the hardiest member of this family found in the United States and 

 winters to some extent within our borders. Throughout the more northern por- 

 tions of its range it is only a summer visitor, but in southern California and 

 Arizona it is found throughout the year. Mr. F. Stephens writes me: 



"The White-throated Swift is a rather common resident in southern Cali- 

 fornia. In winter it is somewhat less common, and disappears in stormy 

 weather. In the Colorado Desert, however, it is usually common all winter. It 

 breeds in small colonies in cliffs, usually in the lower parts of the mountains, 

 during May and June. On Mai-ch 28, 1890, at Boregas Spring, on the border 

 of the Colorado Desert, I saw several White-throated Swifts flying in and out of 

 crevices of a sandstone cliff. I succeeded in climbing to one of these crevices, 

 and chopped away a part of the soft sandstone or indurated clay and found two 

 birds, evidently a pair, in the extreme back end of a narrow crevice. They 

 were sitting on a small bunch of short twigs and weed stems, glued together 

 into a nearly solid mass, evidently an old nest. The female, on dissection, 

 proved to be not nearly ready for laying, as the ovaries were in the normal 

 winter condition." 



There are numerous records of the occurrence of the White-throated Swift 

 in Arizona, New Mexico, and Colorado. I have seen hundreds of these birds 

 near Tucson, Arizona, some throughout nearly every month in the year, and 

 they evidently breed in the vicinity, in the numerous cliffs in the Catalina and 

 Rincon mountains. Mr. W. G. Smith and Mr. A. W. Anthony met with it in 

 Colorado, where it was quite common in suitable localities. The latter writes 

 me: "A few nest in the high cliffs above Silverton, Colorado, with Cypseloides 

 niger. A female was shot by Mr. F. M. Drew on June 20, at an elevation of 

 about 13,000 feet, and upon skinning her an egg was found ready for extrusion, 

 but it was unfortunately broken. A flock of these Swifts were apparently trying 

 to winter at Hatchita, New Mexico, as I saw them constantly as late as Decem- 

 ber 15. At San Diego, California, they winter in abundance, and are frequently 

 seen feeding along the beach north of Point Loma. A colony was also found 

 by me nesting on Coronado Island on May 20, but the nests were inaccessible; 

 they were placed behind loose slabs of rock that had become partly detached 

 from the face of the clifF, and from 20 to 30 feet above the water level. At 

 Guadalupe Island this Swift was very abundant; the ragged, precipitous sides 

 of the island, composed of lava and perforated with thousands of holes and 

 crevices, furnish an abundance of nesting sites, and it is quite probable that this 

 species is resident there throughout the year. At the time of my visit, in May, 

 I found White-throated Swifts everywhere, from the top of the island, at 4,000 

 feet elevation, to the beach, and birds were constantly seen to enter holes in the 

 crags; but in every case the nests were as inaccessible as it is possible for a nest 

 to be. On May 18 a Swift was seen to enter a hole in the face of a bluff, within 8 

 feet of its base; even this proved to be as safe as any of the rest, as the nest was 

 found to be out of sight and several feet back, in a narrow crack in the lava. I 



