254 BULLETIN 17 6, UNITED STATES NATIONAL MUSEUM 



they were feeding. After a succession of lieavy showers which occurred at 

 this place early in July they suddenly and wholly disappeared. At San Jos6 

 del Cabo a few were seen at intervals through the autumn up to November 

 11, and several were observed near Santiago on December 3. * * * It seems 

 fair to assume that the December instance * * * was not exceptional, and 

 that at least a few birds regularly winter in the Cape Region. Mr. Frazar 

 obtained a set of two eggs, slightly incubated, at Pierce's Ranch, on July 20. 



We have no reason to think that the habits of the San Lucas night- 

 liawk differ materially from those of the closely related form found 

 farther north. 



The measurements of 9 eggs average 25.6 by 18.8 millimeters; the 

 eggs showing the four extremes measure 27.4 by 18.8, 26.0 by 19.8, 

 23.1 by 18.1, and 25.6 by 18.0 millimeters. 



Order MICROPODIIFORMES 

 Family MICROPODIDAE: Swifts 



NEPHOECETES NIGER BOREALIS (Kennerly) 

 NORTHERN BLACK SWIFT 



Plates 40-43 

 HABITS 



I prefer to follow Ridgway (1911) in the use of the above com- 

 mon name. The name black swift properly belongs to the type race, 

 Nephoecetes niger mger (Gmelin), which is found in the West In- 

 dies. Moreover, Baird (1858) and some other early writers called 

 it the northern swift. The range of the northern black swift, as 

 now understood, extends from southeastern Alaska to southern iMexico, 

 including much of the Rocky Mountain region, Colorado, New 

 Mexico, Nevada, and California. It breeds wherever it can find suit- 

 able rocky cliffs in which to nest, but as these are widely scattered 

 its distribution is naturally spotty; however, its marvelous powers 

 of flight carry it over a large expanse of country, far from its nest- 

 ing area. 



Tlie northern black swift is somewhat larger than the type race, 

 but it is apparently similar to it in coloration. 



Baird (1858) states: "This remarkable swift was first indicated 

 as North American by Dr. Kennerly (1857), in the proceedings of 

 the Philadelphia Academy, where it is described as Cypsehis horealis. 

 It was obtained in the northern part of Puget's Sound, at Simiahmoo 

 bay, the locality of the main camp of the Northwest Boundary Sur- 

 vey. A large flock was seen one day sailing about the camp, but, 

 owing to the height at which the birds flew, only one specimen 

 could be procured. 



