THE BURROWING OWL. Q7 
farther disturbed, their flight is continued until they 
are no longer in view, or they descend into their 
dwellings, whence they are difficult to dislodge. The 
burrows into which these owls have been seen to 
descend, on the plains of the river Plortte, where 
they are most numerous, were evidently excavated 
by the marmot, whence it has been inferred by Say 
that they were either common, though unfriendly 
residents of the same habitation, or that our owl 
was the sole occupant of a burrow acquired by right 
of conquest. The evidence of this was clearly pre- 
sented by the ruinous condition of the burrows ten- 
anted by the owl, which were frequently caved in, 
and their sides channelled by the rains, while the 
neat and well-preserved mansion of the marmot 
showed the active care of a skilful and industrious 
Owner. 
‘““We have no evidence,” adds Bonaparte, “ that 
the owl and marmot habitually resort to one bur- 
row; yet we are well assured by Pike and others, 
that a common danger often drives them into the 
same excavation where lizards and rattlesnakes also 
enter for concealment and safety. Throughout the 
region traversed by the expedition, the marmot was 
unquestionably the artificer of the burrow inhabited 
by the owl.’* | 
CHAPTER II. 
GROUND BUILDERS. 
Tue essential requisites of a bird’s nest are warmth 
and security, a certain degree of heat being indis- 
pensable for hatching the eggs and fostering the 
* C. L. Bonaparte, Amer. Ornith. vol i., p. 72. 
