PHYSIOLOGICAL STUDIES OF THE RUFFED GROUSE 



751 



elaborate physiologic investigation on grouse. Therefore, attention was directed chiefly to 

 those physiological activities which are intimately associated with the production and main- 

 tenance of body heat, namely, body temperature, breathing and heart rate; ingestion and 

 digestion of food and water; and change in body weight. 



Experimental birds were supplied from hand-raised stock at the Research Center. At the 

 laboratory, when not on experiment, they were held in a tem|)erature-regulated room under 

 natural lighting and were fed the usual ration employed at the Center. One must bear in mind, 

 however, that there are undoubtedly some differences between the reactions of such birds and 

 those of wild grouse. 



Determination of Body Temperature and Respiration Rate 



Experiment 1 dealt with the determination of the average body temperature and respiratTon 

 rate of adult grouse under conditions of normal cage acli\ itv. Cunnilative data from ten 

 birds were secured on consecutive days for several weeks under identical environmental con- 

 ditions. The results are presented in table 102. 



TABI-E 102. 



AVEIUCK MKCTM. TI;MI>1:H \Ti;nK AND HRSPIHATION IVVTK OF. 

 ADULT GHOUSi:* 



^Normal cage activity. 



Comparison of the average rectal temperature and res|>iiatiiiM lalc iridiiates some signifi- 

 cant biological difTcrences lietween sexes. The morning |pni|)crature and respiration rate of 

 the male grouse were higiicr than those of the females, in tiie afternoon res])iration rate was 

 higher for the males but both sexes were (juilc similar as to temperature. 



There was a consistent rise among indi\iduals of the same sex between average morning 

 and afternoon temperatures, indicating that tlie higher afternoon level represents a real 

 physiological difference. A similar relationship was also noted between rectal temperature 

 averages secured at 6.5°F. and 85°F. In this case statistical evaluation of the data indicates a 

 direct effect of air tem])erature itself upon metabolic processes. 



Diurnal Trend in Body Temperature 



Experiment 2 was undertaken to establish the diurnal trend in body temperature. Two 

 groups of birds were used, each com|jrising five male and five female grouse. Rectal tem- 

 peratures were taken for each group at regular 3-hour intervals for two separate 24-hour 

 periods beginning in one case at 8:30 a. m.. in the other at 10:00 a.m. This procedure per- 

 mitted plotting the data at intervals of 1 Vl' hours. With one exception (the factor of light) 

 both groups were subjected to comparable conditions of environmental temperature, activity 

 and food. With respect to light. Group A was exposed to an additional hour of illumination 

 at night. 



