384 ANIMAL LIFE IN THE YOSEMITE 



and the structure was on the south side of the trunk resting on three small 

 branches of the whorl which at that height emanated from the trunk. 

 The nest, when once located, was easily seen on the open side even from 

 a distance. It was a bulky affair, decidedly larger than the usual Robin's 

 nest. It was solid in construction, with a large external basal framework 

 of dead and more or less weathered twigs of irregular shape and small 

 diameter (2 millimeters or less). Many of these were black oak twigs 

 while others were of a very furrj' herbaceous plant. All of the material 

 of this outer framework, as was attested b}- the clean, fresh-appearing ends 

 of the pieces, had been freshly broken off by the jays. This suggests that, 

 save for the small amount of herbaceous material, all the outer constituents 

 were gathered above the ground. The outside framework measured about 

 300 millimeters (12 inches) in one direction and 400 millimeters (16 

 inches) in the other. 



The inner cup of this nest was composed of dry needles of the yellow 

 pine, held together by enough mud to give the structure a firm resistant 

 feel. The mud, however, did not extend to the inner surface. The interior 

 of the cup consisted solely of pine needles, which crossed and recrossed 

 so as to make a porous interior lining. This cup was 100 millimeters 

 (4 inches) in diameter at the rim and 68 millimeters (2% inches) deep 

 at the center. Both the nest and the ground beneath were entirely clean 

 of excrement. 



The nest held three young, nearly naked, and hence not over 3 or 4 

 days old. An adult jay had been covering the young, but flushed at the 

 observer's near approach. The bird slipped off quietly to an adjacent 

 tree and there struck a dumb, statuesque pose which was maintained for 

 a minute or so until the observer showed ob\dous interest in the nest. 

 Then the bird set up the usual call, ksch or kschuey, repeated over and 

 over again. This brought another jay, presumably the mate (the two 

 sexes are exactly alike save that the female is very slightly the smaller), and 

 soon afterward two others. All four joined in the vocal demonstration. 

 When the jays first set up their calls, two California Gray Squirrels, a 

 Sierra Chickaree, and a pair of Spurred Towhees began to call, but these 

 all quieted down after a time. When the nest was removed from the tree 

 for closer study the four demonstrative jays came close about and called 

 in raucous chorus, but after a while they began to move away and changed 

 their calls to the more wooden-sounding type of note. Thus the Blue- 

 fronted Jay exhibits a marked concern over the disturbance of its own 

 home. 



It remains to tell the jay's relation to other birds at this season. Bird 

 students have for j^ears known that the Blue-fronted Jay, like its lowland 

 counterpart, the California Jay, is a merciless plunderer of the nests of 



