2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 'J2. 



were available, so that mistakes were made, and early records had to 

 be abandoned. Continued experimentation led to definite methods 

 that promised accuracy, and it is upon these that the following account 

 is based. The results of studies covering the period from January, 

 1912, to October, 1919, are included herewith, giving a total of 1,558 

 records covering observations on 327 species of birds distributed 

 among 50 families. If the number of observations seems small 

 compared to the length of time involved it must be considered that 

 the taking of temperatures was not always feasible as the difficulties 

 attending the task were manifold and varied. 



The results of this work are embodied in a series of tables which 

 form the foundation upon which this report is based. In addition 

 to the 327 species of birds on which observations regarding body 

 temperature have been made by the writer personally, a supplementary 

 compilation has been given (in table 5) embodying published records 

 on this subject for other species, in order to render this account of 

 the body temperatures of birds as complete as practicable. In this 

 final table records are given forj 89 forms, so that in the following 

 pages may be found definite statements regarding the temperatures 

 of 416 species of birds. It is hoped that the work of securing such 

 records may be continued until a much greater amount of informa- 

 tion covering many more species is available. 



It was the original intention to incorporate in this paper a table 

 giving in detail the individual records upon which the work has 

 been based. Such a course was desirable as it would have furnished 

 a mass of data far greater than any hitherto available for those who 

 may be interested in using such information in lines of research other 

 than that in which it has been utilized here. In addition it would have 

 given opportunity to check up more carefully the deductions that I 

 have made. Cost of printing of tabular matter has proved so high 

 at the time of publication that it has been necessary to omit such a 

 detailed statement and to supply the records only in a condensed form. 

 The table itself is, however, deposited in the files of the Smithsonian 

 Institution and may be consulted by those interested in using it. 



From his studies in the subject of avian body temperatures the 

 writer has ventured to come to certain conclusions and deductions, 

 some in accordance and some at variance with modern ideas as previ- 

 ously accepted. If these seem sufficiently substantiated to meet the 

 approval of others, then may the time and labor required in the 

 compilation of these data be deemed justified. The following pages 

 are respectfully submitted for attention, with the hope that part if 



