Recently published Ornithological Works. 363 



30. Beebe on Geographical Variation in Birds. 



[Geographic Variation in Birds, with especial Reference to the Effects 

 of Humidity, Bj C. William Beebe, Curator of Birds. Zoologica : 

 Scientific Contributions of the New York Zoological Society. Vol. i. 

 No. 1. New York, 1907. 8vo. 42 pp.] 



It has long been known, says Mr. Beebe in commencing 

 this essay, that many mammals, birds, and reptiles which 

 inhabit a humid region shew a much darker or more increased 

 pigmentation of the hair, feathers, or scales than individuals 

 of the same species from drier localities. Correlated with 

 this variation in colour is often a distinction in point of size 

 of either the body as a whole or of parts of it. Among the 

 l)est-known examples of this phenomenon in North America 

 in the class of Birds are certain species of Colinus and 

 Melospiza, of which particulars are given. The more or 

 less regular occurrence of dark-coloured forms among certain 

 wild birds is also well known. Mr. Beebe quotes the case 

 •of Sabine's Snipe in Europe, and of the Rough-legged 

 Buzzards (Archibuteo) in America as instances, and gives 

 other notable examples *. 



After discoursing on various points of this subject, Mr. 

 Beebe gives us an account of some experiments made in the 

 Zoological Park of New York by confining certain birds in 

 a super-humid atmosphere, when "a, radical change in the 

 pigmentation of the plumage has been found to take place 

 with each succeeding moult." This is shown especially in 

 some Doves of the genus Scardafella, in which individuals 

 thus treated were found to pass into a form more nearly 

 resembling that of a different geographical race than that 

 to which they really belonged. These experiments are 

 certainly of much interest, but should be carried out at 

 greater length, we think, before any definite deductions can 

 be made from them. 



* We do not quite agree that the case of the Black-winged Peafowl 

 {Pavo nigripennis) belongs to this category, as the female is quite distinct 

 from that of P. cristatus [cf. Sclater, Bull. B. 0. C. vi. p. xii, 1896). 



