BIOACOUSTIC AND BEHAVIOR IN THE SOUTHERN FLYING SQUIRREL (GLAUCOMYS VOLANS), A 
KEYSTONE RIPARIAN MAMMAL.

Deborah L. Beal and Tony Meyer
Illinois College, Jacksonville, Illinois, USA 62650, 217-245-3463			
	
						
Southern Flying Squirrels Glaucomys volans are elusive nocturnal arboreal 
mammals which have been identified as “keystone species” in Riverine Floodplain 
and Deciduous forests throughout the eastern United States and Canada.   Many 
ecological studies of the species have been done but little analysis of their 
vocal repertoire, or predator avoidance behavior exists.  In this study we 
evaluate acoustic and behavioral responses to predator calls among varying age 
and gender classes and document acoustic signals used by flying squirrels to 
communicate.  This information may be important in helping to census and 
identify individuals in the field.  

A captive colony of 16 - 22 individuals of varying ages and gender, housed in an 
outdoor 8' x 8' x 6' wire mesh pen were studied over a three month period. 
	Several different methods were used to acquire acoustic data.  First, 
calls made at random in the colony were recorded and analyzed for 10 days each 
in May, June and July.  Then, individual males and females, and juveniles were 
isolated and calls between the individual and the colony recorded.  Finally, 
predator calls of Barred and Great Horned Owls were broadcast and the responses 
of individuals of varying gender and age were recorded.   Squirrels were video 
taped and photographed during broadcasts to evaluate behavior responses.

Flying squirrels communicate with high pitch chirps and squeaks. Call frequency 
ranged from 4- 24 Hz/1000.   There were significant differences in the number of 
calls made by males and females and the response of each to predator calls.  
Males were more significantly more likely to sound an alarm call than females 
(ttest = .08) in response to predator signals. Infants less than 4 weeks 
communicated with inaudible high frequency calls when separated from their 
mothers (>18 hz/1000). There was some indication that flying squirrels have the 
capacity for ventriloquism such as that used by western ground squirrels. 
Observers were only able to identify individuals sounding alarm calls from 
different areas by watching thoracic movement and sounds appeared to originate 
from outside the pen.  Last, individuals separated from the colony responded to 
colony callers when placed more than 100 feet away which may indicate that sound 
is one method used to join up to form colonies during the winter.  

Keywords: riparian, flying squirrel, behavior, predator response, Glaucomys 
volans