768 



PHYSIOLOGICAL STUDIES OF THE RUFFED GROUSE 



the finding of a negative coefficient for birds actively digesting food and a positive coefficient 

 for fasting birds. The values of both coefi'icients are biologically very high and demonstrate 

 a strong relationship between air temperature and digestive activity. 



I'Mui: 111. n\ri': ok digestion ok adult (jkouse kvteh fasting a.t 



DIFFERENT AIR TEMPERATURES 



T\L5Ll-: 11.5. UEL.VnoNSHll' BETWEEN EN\ IHO.NMENTAL TE.MPER.VTIIVK 



AND DIGESTIVE ACTIVITY 



temperature; y = rate of disestion. 



Physiologically the high negative correlation coefficient is interpreted to mean thai when 

 environmental temperature decreases the length of time required for food to pass through 

 the alimentary canal increases. Under these conditions metabolism would be stimulated by 

 cold but food substances would be retained longer in digestive ])rocesses in order to exhaust 

 and absorb all of the possible available niitriinerits. At high air temperatures the reverse 

 would be the case for actively feeding birds. 



The high positive coeflicient is of considerable plnsiologic interest. It suggests that expos- 

 ing a fasting grouse to lowering environmental temperature decreases the length of time 

 required for food to digest and be voided as excreta. Greater oxidation of cellular tissue (at 

 from 78 to 100 hours of fasting, essentially a fat metabolism I to combat cold ajiparently 

 stimulates metabolism considerably. .\t higher air temperature the rate of digestion of fast- 

 ing birds would also increase. 



These two observations on digestive aclivity in relation to air temperature are of con- 

 siderable importance in evaluating the probabilit\ of sur\ival of game species during winter 

 months, especiallv during hours of darkness. Regardless of the temperature effect, the rate of 

 passage of digestible substances through the aliinentar\ c aiial nf the fasting bird was cnnsid- 

 erably faster than for the feeding bird. 



Rki.ationsiiip of Ckktmn Fmiods to Maintenanck ok I><>l)^ \\'ki(;ht and Vit.ality 



Kxpcrinient ') iiuoKed llii' lelatimiship nf certain food rations tn tiie inainlenanci' of bod\ 

 weight and \italil\ aimmg adult grouse. I'oods \ar\ ^^ilh respect to their nutritive \alue. If 

 a change occurs in the composition of the food ration. <ii in the anioiint of fnod consumed 

 daily, there ma\ follow appreciable changes in body heat picidiiclion. in cornixisition of bod\ 

 tissues and in body weight. When catabolic processes (the breaking down and destruction of 



