48 



WILD ANIMALS OF fILAOIER NATIONAL PARK. 



ffachdooi 



Toihf 



bushels of earth and stones brought from the burrow, and the lower 

 part was packed and hard as though an accumulation of several years. 

 There were two other openings farther back from which no earth 

 had been thrown and evidently thoy had been tunneled to the surface 

 from below. The main shaft of the burrow was usiudly ;> or -1- inches 

 in diameter, and back a couple of feet from the entrance, just before 

 the burrow forked into two main shafts, was a roomy chamber where 

 the sfjuirrels could turn around and sit up comfortably, a sort 

 of reception room. Kear secondary forks were also two other 

 chambers which may have served several purposes, such as con- 

 venience in storing earth brought out of the tunnels, or places of re- 

 treat from whicli to watch for enemies that might enter the burrow 



from either direction. Well back 

 about 8 feet from the entrance and a 

 foot below the surface of the ground 

 was a lai'ge nest chamber about a foot 

 in diameter nearly filled with old soft 

 nest material. The nest was composed 

 almost entirely of the soft flat leaves 

 of the brown " glacier grass " {Jun- 

 coi/les parvifloruTn) which abundantly 

 covers the mountain slopes. At the 

 bottom it was damp and moldy, but 

 from the bed in the center to the top, 

 it was dry and clean, and a few fresh, 

 green blades had been brought in for 

 food or nest material. It had evi- 

 dently served as winter quarters for 

 the old squirrel and as a nest for her 

 young and was being prepared for the 

 coming winter. From one side of the 

 nest chamber the burrow led down to 

 an older and deeper chamber of some 

 previous year, containing at the bottom an old rotten nest half full 

 of excrement. A tunnel ran from it back toward the main entrance 

 and into the main tunnel near the middle, making an easy way of 

 escape if an enemy should dig to the first nest. Back of the nest a 

 small shaft led to the surface of the ground and another opened 

 out at the end of the first main fork of the tunnel. These rear open- 

 ings were half concealed in the grass and evidently were for use as 

 avenues of escape in case the burrow should be entered by a weasel 

 or dug out hy bear or badger. 



Many places were found where bears had dug for the squirrels, 

 teai'iug up great tough sods of bear grass and even small trees and 

 large stones in their effoits to get at the nest. In many cases they 



F'IG. 7. — Plan of underground den of 

 Columbia ground squirrel as ex- 

 cavated and mapped near Piegau 

 Pass, July 2T, 1917. 



