354 AXIMAL LIFE IX THE YOSEMITE 



It Avas noted that one or more Anna Hummingbirds were to be found 

 regularly about a certain golden oak, but the reason for their attraction 

 to this particular tree was not discerned for several days. Then, on Decem- 

 ber 11, one of these birds was seen hovering before, and drinking from, 

 some punctures made by a Red-breasted Sapsucker in the bark of the 

 oak tree. The hummer visited puncture after puncture just as it would 

 the individual blossoms in a spike of flowers, and evidently partook of 

 both the sap and the smaller of the insects which had been attracted by 

 the sap. Ruby-crowned Kinglets and California AVoodpeckers were also 

 visiting the place, in addition to the sapsucker which had done the work. 

 Thus the hummers, kinglets, and woodpeckers were all benefiting by the 

 industry of the sapsucker without evident disadvantage to the latter, 

 whereas all profited at the expense of the oak tree. 



In May, Anna Hummingbirds were foraging among the flowers on the 

 greasewood slopes about Pleasant Valley. A female taken at this time 

 (May 30) had a yolk in the ovary; this w^ould suggest breeding activity 

 at a relatively late date for this species here. It is elsewhere known to nest 

 as early as February, or even January. 



Rufous Hummingbird. Selasphorus rufus (Gmelin) 



Field characters. — Chin and throat of male iridescent coppery red, abruptly bordered 

 below by white; back of male entirely cinnamon rufous, and plumage otherwise mostly 

 rufous; back of female iridescent bronzy green; sides of body and base of tail strongly 

 tinged with rufous. Adult males in flight give forth a tremulous whistling sound. 



Occurrence. — Common transient through the Yosemite region. Observed by us 

 as follows: near Yosemite Point, July 1; head of Lyell Canon, July 23; Washburn 

 Lake, August 24; top of Parsons Peak, September 6; and Silver and Walker lakes, 

 September 14; all dates in 1915. Also, at Smith Creek, 6 miles east of Coulterville, 

 August 8, 9, and 10, 1920. 



The Rufous Hummingbird was observed by us only as a transient in 

 the Yosemite region; indeed this species is not definitely known to be 

 other than a transient anywhere in California. The passage of the last 

 northbound spring migrants is so closely approximated by the beginning 

 of the southbound movement in the early summer that individuals are 

 likely to be seen in the region on almost any day during the summer 

 months. Most of the northbound movement probably takes place at low 

 altitudes and in any event occurs too early in the spring to be observed 

 bj^ most visitors to the Yosemite section. But the migration initiated 

 in late June or early July continues until the middle of September, and 

 especially at tlfe higher altitudes is much in evidence. 



The adult males take no share in the duties of nesting, which arc 

 carried on in the northern Rocky Mountains and in the Pacific Coast 

 district north from Oregon; the first representatives of the species to 



