1922,] Recently published Omit /lological Works. 367 



Two of these, Pipromorpha macconelli amazona from the 

 Lower Amazon valley and P. ohag'ina pacifica from western 

 Ecuador, are described as novelties. 



Wetmore on Birds' temperature. 



[A study of the body temperature of Birds. By Alexander Wetmore. 

 Smithsonian Miscell. Collect, vol. 72, no. 12, pp. 1-52, 1921.] 



For some years past Mr. Wetmore has been making 

 observations on the temperature of birds whenever an 

 opportunity occurred, and he lias now published a complete 

 record of his observations on over 300 species, to which he 

 lias added notes on some further 200 species from availal)le 

 literature. He has therefore a good basis of fact from which 

 to deduce results. As is well known, the body temperature 

 of birds is higher than that of man, varying from about 

 100° F. to 110° F. in exceptional circumstances. It is 

 interesting to find that there is a marked diurnal variation 

 in temperature in the case of small birds, often as much as 

 6° or 7°, the highest temperature being in the middle of the 

 day, the lowest at night ; but in Owls, whose activity is 

 chiefly nocturnal, the reverse is the case. In the case of 

 nestlings, those species which are altricial show a much 

 lower average temperature than adults, and are undoubtedly 

 much dependent on their parents for warmth. It has been 

 found, hoMCver, that the temperature of such birds may be 

 reduced to 97° without death resulting. ]\Ir. Wetmore 

 suggests that the air-sacs, the physiological function of 

 which has been a moot point for many years, may be of use 

 for regulating the temperature of birds in the absence of 

 sweat-glands, and he brings forward several cogent argu- 

 ments in favour of this hypothesis. Finally he points out 

 that birds which are generally considered lowly organized, 

 such as Grebes, Herons, and Pelicans, have a distinctly lower 

 temperature than Pigeons, Woodpeckers, and Passeres : 

 this is well brought out in one of the tables of the average 

 temperature of families of birds. This is an important paper 

 and well worthy of attention. 



