SHORT-TAILED CHICKADEE 359 



J. E. Patterson has sent me a photograph of a nest that was in the 

 under side of the bole of a prostrate pine log, only a few inches above 

 the ground. 



Mr. Griffee says in his notes : "Nesting cavities usually are 4 to 8 

 feet above ground and situated in lodgepole pines when that species 

 is available. Often they will choose a live lodgepole tree, even when 

 punky aspen stubs are available. Nesting pines often have heart rot, 

 which makes the excavating easier than it looks from the outside, but 

 nevertheless the work of excavation must be several times as arduous 

 as that usually performed by the Oregon chickadee. Entrance holes are 

 about 1^ inches in diameter and often go straight back as much as 

 4 or 5 inches to the heart of the tree before turning down for 8 to 12 

 inches. The bottom of the cavity, often irregular in shape because of 

 an intruding knot, is lined with more or less shredded bark upon which 

 is piled a lot of rodent fur. As the fur is short and not felted together 

 compactly, the nest will not hold its shape when removed from the 

 cavity. 



"In my experience, the short-tailed chickadee always stays on the 

 nest from the time the first egg is laid. Probably this is necessary 

 because of the great abundance of chipmunks, which are small enough 

 to run into a chickadee nesting hole and make a meal of the eggs, if 

 the parent bird were not on the job at all times. The Oregon chick- 

 adee, which nests where chipmunks are much less common, and makes 

 a smaller entrance to its nesting cavity, apparently is not so much 

 bothered by chipmunks and so does not hesitate to leave its nest un- 

 guarded until incubation begins." 



Eggs. — The eggs of the short-tailed chickadee apparently do not 

 differ materially from those of other races of the species. They are 

 mostly plain, pure white, but usually some of the eggs in a set are 

 more or less finely speckled with reddish brown. The numbers I have 

 seen recorded run from five to nine in a set. The measurements of 

 40 eggs average 16.1 by 12.3 millimeters; the eggs showing the four 

 extremes measure 17.0 by 11.9, 16.5 by 13.2, and 14.7 by 11.4 milli- 

 meters. 



Young. — Grinnell, Dixon, and Linsdale (1930) noted one case where 

 tvv^o broods were raised in a season in the same nest ; probably two 

 broods are often raised. At a nest that they watched the young were 

 fed 11 times within half an hour, between 8.59 and 9.30 a.m., at inter- 

 vals varying from one to seven minutes, but usually at intervals of 

 three or four minutes. Such food as could be seen consisted of green 

 caterpillars. Both old birds helped in the feeding and in keeping the 

 nest clean, carrying away the excrement sacs. 



