CHIPPING SPABBOW 455 



altitudes, nesting comes later, probably because, due to the persistence 

 of a low temperature there to a later date in the spring, sufficient food is 

 not available earlier. But the discrepancy from this cause is not so great 

 as might be supposed. At the lower levels the chipping sparrows nest after 

 the first burst of bloom from the herbaceous plants is over, whereas around 

 the high mountain meadows the birds have their nesting already well under 

 way when the alpine flowers have only begun to appear. Thus, to a certain 

 degree, the spring calendar for the birds is different from that for the 

 flowers. The birds maintain their own body temperature in spite of the 

 prevalent conditions about them, and may therefore be controlled more 

 directly by other factors, such as that of available supply of food. 



At El Portal on the morning of April 27, 1916, a male chipping sparrow 

 was seen in courting display before a female. He uttered notes sharper 

 than the usual ones, more like the syllable tsd, uttered singly or trilled in 

 series. As the notes were given, each was accompanied by a slight shrug 

 of the body and downward movement of the tail. The two birds passed 

 back and forth, hopping and flying, amid red-bud, buckeye, and live oaks. 



A majority of the nests of this bird are placed between 4 and 6 feet 

 from the ground; very few are more than 12 feet up. The lowest nest 

 found by us in the Yosemite section was only 2 feet above the ground and 

 the highest approximately 16 feet. Almost any sort of tree or large bush 

 is used for a site. In a bush or small tree the nest is most often placed 

 near or at the top ; while in a large tree it is situated near the end of a 

 lower outreaching branch. "We saw nests in blue oak, live oak, incense 

 cedar, yellow pine, lodgepole pine, and orchard trees, as well as in deer 

 brush and wild rose, and once in a cultivated blackberry vine. 



The nests of the Western Chipping Sparrow are of such an unique type 

 that they may be readily identified without the necessity of seeing the 

 makers. No other bird of the Yosemite region builds a nest of the same 

 form or constituency. The foundation is of long fine weathered stems of 

 grasses and other plants, so laid together and interlaced that they con- 

 stitute a firm yet porous structure not easily shaken to pieces. Internally, 

 the, nest proper is of a deep cup-shape, walled with a neatly woven layer 

 consisting solely of long mammal hairs, wound about so as to produce a 

 perfectly smooth interior surface. This inner lining is so well woven that 

 it can be lifted free of the foundation part of the nest and still retain its 

 shape, almost like a piece of hair cloth. This type of nest seems well 

 adapted to the kind of site preferred by the chipping sparrow, namely, the 

 outer loose foliage of trees, upon a large area of which the nest platform 

 can rest without danger of disintegration or of falling from place. The 

 nest cavity measures in ascertained cases 1% inches in diameter by II/4 



