PHYSIOLOGICAL STUDIES OF THE RUFFED GROUSE 



757 



quently throughout the tests. It apparently is not a result of visible muscular activity for the 

 birds were quiet when the change occurred. More probably it is caused by cellular varia- 

 tions in heat production and the subsequent flow and distribution of heat throughout all 

 parts of the body. 



RR 72 

 ^ KR 324 



H R - Heart Rate 



R R - R«apiratior^ Rate 



A - Activity Cnoturat) 



EXCITED-Artificolty Stimulated 



2 107 I 



go 100 120 140 160 leo 



DURATION OF TEST IN MINUTES 



220 



20 40? 60 



ii(;iKE f>R. piivsioLOGie reactions ok two <;k()1 se to kepose 



The rate of metabolic activity was more rapid at the beginning of the test, but as a basal 

 condition was approached the rate decreased. When final basal levels were reached both 

 of the grouse (representative of ten individuals! were removed from the "holding board" 

 (figure 89) and excited emotionally and muscularly. The result of this stinmlation was 

 quickly reflected by pronounced increases in body temperature, respiration and heart rate. 

 These results again clearly demonstrate the intimate relationship between environmental con- 

 ditions and physiological phenomena. 



Next the rate of heart beat was established fm Imlli feeding and fasting grouse at different 

 air temperatures. In these tests the heart rate was classified under three headings, that is, 

 (1) the standard rate of the inactive bird held for studv immediately after remo\al from its 

 cage; (2) the standard quiet rate of the inactive liird held quietly for some time after re- 

 cording rate No. 1; and (3) the excited rate resulting from muscular stinndation. The air 

 temperature indicated is that to which the birds were accustomed to living before testing. 



The results for feeding birds are presented in table 104. Throughout these tests the heart 

 rate of birds with food was higher at 40°F. than at 65°F. 



Immediately upon removal from the cage, female grouse exhibited a faster heart rate than 

 males at both OST. and 40^"F. As indicated by the standard deviation the range of varia- 

 bility among both sexes was considerable. In all observations the lowest range for females 

 was approximately equivalent to the highest range for males. Likewise, after the birds had 

 had an opportunity to quiet down, the same relationships existed. 



