222 University of California Publications in Zoology ["Vol. 24 



The parent of the second set was extremely solicitous of their safety. 

 She flew as we approached, coming toward us with a peculiarly halting 

 and uncertain flight, with her tail depressed until it pointed almost 

 straight down, and with her mouth open. Alighting near-by, she 

 wallowed on the ground, thus luring us in pursuit for about twenty or 

 thirty yards, then flew off in a circle through the woods. The parent 

 of the set at Doch-da-on Creek acted quite differently. She left the 

 eggs while the intruder was still some distance away, departing quietly 

 and without any manifestations of solicitude. In just twenty minutes 

 she returned, as secretively as she had left. This course of action was 

 followed without variation on three different occasions. 



Foui* specimens were collected (nos. 39790-39793), two adult males 

 and two adult females. To my eye they are indistinguishable from 

 specimens of Chordeiles v. virginianus from the eastern United States. 



Cypseloides niger borealis (Kennerly). Black Swift 



A few seen about six miles from Telegraph Creek on June 12, 

 circling overhead just out of gun shot. From this circumstance the 

 species may be assumed to breed somewhere in that general region. 

 One or two were observed at Glenora early in July. The next place 

 the species was noted was at Great Glacier, where, on the morning of 

 August 9, a flock of fifteen or more was seen. . 



At Sergief Island, August 17 to September 7, black swifts were 

 abundant, though seen only in cloudy or rainy weather. Then large 

 flocks appeared, as many as seventy-five or a hundred being in sight 

 at once flying over the marshes, the individuals moving about in wide 

 circles, and the flock as a whole moving in a definite path. The birds 

 sometimes flew very low, occasionally skimming along just over the 

 tall grass. A flock would appear, circle about overhead awhile, and 

 then vanish. About fifteen or twenty minutes later, others, or perhaps 

 the same fiock, would come in sight again. 



Compared with Aeronautes and Chaetura, the fiight of Cypseloides 

 (at least as seen thus feeding) is rather slow, a steady sailing with 

 relatively little fiuttering of the wings. A high rate of speed can be 

 attained, however, so great that when individuals passed by in pursuit 

 of one another the rush of their wings could be heard to a distance of 

 two hundred yards or more. A weak, chattering note was uttered 

 from time to time, but mostly the birds were silent. 



Seventeen specimens were obtained at Sergief Island (nos. 39794- 

 89810), five males and twelve females. It might be supposed that a 



