NO. 12 



BODY TEMPERATURE OF BIRDS WETMORE 



heit, or even lower, it would seem probable that it would be necessary 

 to take some steps to use thermometers that had been previously 

 heated at least to a slight degree. This fact may be readily determined 

 by observation. It is probable that save in the most extreme cold 

 weather error from using unwarmed instruments would not amount 

 to more than a few tenths of a degree. 



The observations recorded in the tables at the close of this paper 

 are to be regarded at best as approximations to the actual tempera- 

 ture of the birds handled. In treating data of this nature taken 

 by force from the lower animals we can only assume that we are 

 correct in our observations. Through experience we may establish 

 what we consider as the normal limit of variation, but in many cases it 

 is difficult to be assured that we are absolutely correct. Through long 

 experience the writer believes that the records presented are a portrayal 

 of the conditions as nearly correct as may be with the instruments used. 



DIURNAL RHYTHM IN TEMPERATURE 

 The question of the diurnal rise and fall of temperature in a few 

 species of birds and animals has been carefully investigated by Simp- 

 son and Galbraith.^ These authors, on two dififerent occasions, secured 

 records of the body temperature of living gulls, starlings, sparrow- 



Table I. — Time of maximum and minimum temperatures in birds 

 (Taken from Simpson and Galbraith) 



Species 



Domestic fowl d 

 Domestic fowl 9 

 Bantam fowld" . 

 Bantam fowl ? . 

 Domestic duck d" 

 Domestic duck $ 

 Domestic pigeon d 

 Domestic pigeon 9 



" Seagull " 



" Seagull " 



Jackdaw d 



Jackdaw 9 



Species 



Time of i Time of 



average 



maximum 



temp. 



"Hawk" 4.00p.m. 



"Hawk" 4.00p.m. 



Thrush 12.00 p.m 



Thrush i.oop.m. 



Starling 



Starling I 6.00 p.m 



Starling j 3.00 p.m. 



Owl 3.00 a.m. 



Owl ' 4.00a.m. 



Owl 4.00 a.m.. 



Owl j 4.00 a.m. 



average 



minimum 



temp. 



i.ooa.m. 



i.ooa.m.. 

 12.00 a.m. 



I.ooa.m. 

 3.00 p.m. 12.00 a.m. 



3 00 a.m. 



3.00 a.m. 



9.00 a.m. 

 10.00 a.m. 



7.00 p.m. 



I.oop.m. 



hawks, a kestrel, thrushes, several owls, and domestic fowls, ducks and 

 pigeons, at three-hour intervals for period of a week. The results 

 obtained when tabulated gave curves that agree essentially with simi- 

 lar curves taken for man and other mammals. (Variation in the time 



^ Journ. of Phys., Vol. XXXIII, 1905, pp. 225-238. 



