Sept, 1912 DISCOVERY OF NEST AND EGGS OF CALIFORNIA PINE GROSBEAK 171 
was not particularly easy ; for each Sierran summer is somewhat different from 
the preceeding and what might be termed the “shift” of the Sierran season 
which results from a number of causes, is very puzzling. In lower zones, here 
along the coast, for instance, hummingbirds have been found nesting in January, 
bush-titmice in February, chickadees in March, juncos in April, warblers in 
May, flycatchers in June, and vireos in July. In the High Sierras, however, 
the season of reproduction is very short and with few exceptions all birds 
nest between May 15 and June 30; it is on account of this shortness of the season 
that the “shift” has such a marked effect. Above 7500 feet altitude there are 
but very few resident species and in the lower zones it is this class that con- 
tains the bulk of the early breeders. 
The season of 1910 in the Tahoe region was one of the earliest known to the 
old settlers and, in respect to nesting conditions, was at least from fourteen to 
Fig. 70. HEINEMANN AND DITTDEJOHN ON THE SNOW 
NEAR TIMBEREINE AT ABOUT 8750 FEET ATTITUDE; 
PHOTO TAKEN JUNE 17, 1912, WHILE EN 
ROUTE TO PYRAMID PEAK 
sixteen days earlier than normal. On the other hand, 1911 was a year of very 
heavy snow-fall and about a week later than normal. On June 9, 1910, we found 
only scattered patches of light snow on the F'orni meadow, while on June 11 of 
1911 we found it from 6 to 10 feet in depth. With the coming of 1912 it seemed 
the weather pendulum was swinging back again, for the winter remained remark- 
ably mild in character. We kept a close watch on the snow reports of the U. S. 
Weather Bureau, and the following table shows comparative conditions for the 
last six years on February 28. 
Table showing inches of snow on ground February 28 
1907 
1908 
1909 1 
1910 
1911 
1912 
Summits. P. R. R., Placer Co., 7018 ft. altitude 88 
74 
21,3 1 
72 
215 
23 
Tahoe City, 
Lake Tahoe, 6220 ft. altitude 

‘ 66 
40 
78 
19 
McKinney’s 
Lake Tahoe, 6220 ft. altitude 
— 
; 72 
38 
79 
14 
