D 
     
    
   
   
    
     Low-frequency sound. Some birds can detect 
     
     extremely low—pitched sounds. Since such 
     
     sounds can travel thousands of kilometers 
     
     with little loss in intensity, they may 
     
     possibly be used by some birds as navi— 
     
     gational cues. 
     
    
   
   
    
     Barometric pressure. An organ within the 
     
     middle ear of pigeons is thought to be 
     
     sensitive to slight changes in air pressure, 
     
     and may possibly be useful to the bird in 
     
     forecasting weather conditions suitable for 
     
     migration. 
     
    
   
   
    
     David Cairns 
     
    
   
   
    
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     This is the third article in a series on endangered wildlife in Canada, 
     
     information provided by the Canadian Wildlife Federation. 
     
    
   
   
    
     baSed on 
     
    
   
   
    
     EASTERN COUGAR (Felis concolor cougar) 
     
    
   
   
    
     The eastern courgar is a medium to 
     
    

    
     large dark-coloured subspecies that was 
     
     formerly found over nos: of eastern Mort; 
     
     America. In Canada, it once ranged 
     
     throughout Ontario, southern Quebec, and 
     
     the Maritimes, but is now very rarely 
     
     sighted. Currently, an estimated 100 
     
     individuals are thought to be scattered . 
     
     sparsely throughout the former range, ’ 
     
     with about half of them in New 
     
     Brunswick. Clearing of the eastern 
     
     hardwood forests and the subsequent 
     
     conflict with man drove the cougar to 
     
     the more remote areas of its range. At 
     
     present, there are indications that the 
     
     cougar is slowly re-occupying parts of 
     
     its former range. 
     
    
   
   
    
       
     
    
   
   
    
     \fl‘ 
     
    
   
   
    
     “*4: 
     
    
   
   
    
     VANCOUVER ISLAND MARMOT (Marmota 
     
     vancouverensis) 
     
    
   
   
    
     The Vancouver Island marmot closely 
     
     resembles its eastern cousin, the 
     
     woddchuck, and is found exclusively 
     
     on the rocky mountain sides of 
     
     western Vancouver Island. Never. 
     
     abundant, this marmot is now thought 
     
     to number fewer than 100 individuals. 
     
     Since it occupies such a restricted 
     
     habitat, it is extremely vulnerable 
     
     to sudden environmental change.