210 EVERYDAY ADVENTURES 
and in this position sleeps through the daylight. 
It sleeps through the winter in the top of some warm 
steeple or, far more often than we suspect, in dark 
corners of our houses, and sometimes in hollow trees 
and deserted buildings and caves. Only when 
caught by the cold does the bat hibernate. Often 
it migrates like the birds. 
One of the strangest things about the flittermouse 
is its voice. It is a penetrating, shrill squeak, so high 
that many people cannot hear it at all. The chirp 
of a sparrow is about five octaves above the middle 
E of the piano, while the cry of the bat is a full octave 
above that. In England there is a saying that no 
person more than forty years old can hear the cry 
of a bat. This is founded probably on the fact that 
the ears of many of us, especially as we approach 
middle age, are unable to distinguish sounds more 
than four octaves above middle E. Some naturalists 
believe that the shrill squeak which most of us do 
hear is only one of many notes of the bat, and that 
the various species have different calls, like those of 
birds, and probably even have a love-song during 
the mating season, in late August or early September, 
which can never be heard by human ears. 
Most bats found in the Eastern States are either 
large brown house-bats, one of two kinds of little 
brown bats, black bats, red or tree bats, pigmy bats, 
or, last, largest and most beautiful of all, hoary 
bats. The big brown bat, or house-bat, is the 
commonest. This is the last of the bats to come out 
in the evening, for each has a certain fixed hour when 
