Mar., 1907 FROM FIEIvD AND STUDY 59 



Nesting of the Sierra Creeper.— During the summers of 1905 and 1906 spent in the San 

 Bernardino Mountains of southern California, I became acquainted with the nesting of the 

 Sierra creeper [Ceiihia americana zelotes). The species proved to be more numerous than I have 

 ever seen it elsewhere, in the upper part of the Santa Ana Canyon and on its tributaries and 

 adjacent slopes. While observed from an altitude of 5600 feet in the Santa Ana Canyon to as high 

 as 9500 feet, above I3ry Lake, on the north base of San Gorgonio Peak, yet the creepers were most 

 abundantly represented in the canyons from 6000 feet to 7500 feet. This belt of abundance was 

 also the belt in the Transition Zone where the incense cedar {Libocednis decurrens) is conspicu- 

 ously represented. And it was in these cedars that the majority of the creepers' nests were found. 



While the birds themselves were most often seen and heard high above, scaling the massive 

 trunks of the huge firs, pines, and cedars, yet their nests ranged not higher than twenty feet above 

 the ground. Myself and companions examined iully thirty nests, easily discovered after we once 

 learned how to find them, and of these I should judge the average height to have been six feet. 

 In other words the majority could be at least touched by the hand as we stood on the ground, 

 (^ne nest was only three feet above ground. 



Altho the majority of the nests found were on cedar trunks, one was on a Jeffrey pine, and at 

 least five were on silver firs. In the latter cases the trees were dead and rotting, for it was only on 

 dead trees that the bark had become loosened and separated enough from the trunk to afford the 

 narrow sheltered spaces sought by the creepers for nesting sites. But the huge living cedar trunks 

 furnished the ideal situations. For the bark on these is longitudinally ridged and fibrous, and it 

 frequently becomes split into inner and outer layers, the latter hanging in broad loose strips. The 

 narrow spaces behind these necessitate a very compressed style of nest. A typical nest closely 

 studied by me may be described as follows: 



The material employed externally was cedar bark strips one-eighth to one-half inch in 

 width. This material had been deposited behind the loosened bark until it packed tightlv enough 

 to afford support for the nest proper. The bark strips extended down fully a foot in the cavity, 

 and some of them protruded thru the vertical slit which served the birds as an entrance. The 

 main mass of the nest consisted of shredded weathered, inner bark strips of the willow, felted 

 finest internally, where admixed with a few small down-feathers. This nest proper was six inches 

 wide in the direction perm tted by the space, and only one and three-fourths inches across the 

 narrow way. The nest-cavity was one and one-third by two and one-fourth inches, so that the 

 sitting parent probablj' always occupied one position diametricalU'. 



No nests were found with eggs later than June 11, but young were found, yet unable to fly, 

 until July 20. Two sets of eggs iound on June 11 consisted of four and five eggs, respectively. 

 Broods of young were of three to six individuals, one of the latter number being noted on June 26. 



The ground-color of the eggs is pure white. The markings are elongated in shape length- 

 wise of the egg. The brightest markings are burnt sienna the tint varying from this towards 

 vinaceous as the depth of the markings in the shell-substance increases. The darkest markings 

 average one millimeter in diameter, while the vinaceous ones vary down to mere points. The 

 markings are most crowded around the large ends of the egg-shells, and radiate from this pole in 

 lesser numbers towards the opposite pole. The nine eggs are quite uniform in appearance, tho 

 certain ones are to be distinguished as more sparsely, more boldlj', or more minutely marked. 

 The markings on one set are not so dark as on the other, approaching pale hazel at darkest and 

 ranging to vinaceous-cinnamon. 



In shape the eggs of the Sierra creeper vary from ovate to elliptical-ovate. The two sets 

 measure, in hundredths of an inch: .6rx.45, .63X.42, .61X.44, .60X.44 and .56X.43, .57X.44, 

 .59x44, .55X.43, .58x43.— Joseph Grinnell, Pasadena, California. 



Do Birds Desert Young? — Mr. W. Otto Emerson tells of a newly mated pair of orioles 

 [Icterus bullocki) that he saw one day about a grove of eucalyptus trees. The male was in fine 

 plumage, and he shot it for his collection. The next day the female appeared with a new hus- 

 band who was as bright and fine looking as the bird that was killed the day before. At first 

 chance this male was also shot, partly it was said, because of his fine plumage, and partly to see if 

 the female could find another mate as readily. Two days later she appeared with a third hus- 

 band, who went the way of the two former ones. The female then disappeared for a few days, 

 but returned again with a fourth suitor. These two began building and soon had a home in the 

 eucalyptus grove. This may be a remarkable case of wooing and winning, but very likely the 

 widow oriole was breaking up other families. 



Whenever I have found nests that were deserted when the}- contained eggs or young, I have 

 attributed it to accidental death of one or both of the parents. But this is not always so. 



During the summer of 1905, I was making a study of a family of Bullock orioles that nested 

 in a willow tree. On June 13, there were three half-grown young in the nest. Both male and 

 female were feeding. Suddenly, I noticed a brighter colored male fly over and light in a nearby 

 tree while the father of the nestlings darted at him and drove him off. The next morning I 

 noticed the same male appear and there was another fight. In the afternoon I heard the intruder, 

 singing at the upper end of the orchard. The mother had been feeding her young, but as the 

 hours passed her visits were fewer and I noticed only the male was bringing food. The next day 

 the female had deserted her young entirely, for only the male was about, and he had assumed 

 entire charge of the household. 



It happened that a rain storm came up that night, and as the young birds were not hovered 



