o58 Oberholser, Notes on N. A. Birds. [o"t. 



of very great seasonal changes; and until more is known regarding 

 the actual process and sequence of these changes, it is not safe to 

 use the colors of these parts in diagnoses. 



The European form of the species, Casmerodius albvs albus 

 (Linmeus), which ranges also to Africa and central Asia, is a large 

 bird with long tarsi and comparatively short dorsal plumes, the 

 latter usually less than 370 mm. in length, and not reaching much 

 beyond the end of the tail. Examples from India and Burma are 

 somewhat smaller and indicate intergradation with the Australian 

 bird, but are, however, nearer Casmerodius albus albus. 



The Australian race differs from Casmerodius albus albus in 

 smaller size, particularly of the tarsus, and in somewhat shorter 

 dorsal plumes; and Mr. Mathews 1 has separated it as a fourth 

 race under the name Herodias alba syrmatophora (Gould). There 

 is, however, apparently no difference between birds from Australia 

 and those from the island of Timor, which is the type locality of 

 Ardea timoriensis Lesson, either in the length of the tarsus or the 

 dorsal plumes. Birds from other localities in the Malay Archi- 

 pelago seem to be the same; while birds from Japan and China, 

 although somewhat verging toward Casmerodius albus albus, are 

 so near the Australian form that they are apparently not satis- 

 factorily separable. Thus the birds inhabiting the region from 

 Japan and China to the Malay Peninsula and i\ustralia should 

 again be united under the name Casmerodius albus timoriensis 

 (Lesson). « 



The American bird, which ranges from the United States to 

 Chile and Patagonia, is similar to Casmerodius albus timoriejisis, 

 but is rather larger and has a much longer train; and ft differs 

 from Casmerodius albus albus in decidedly smaller size and in its 

 longer dorsal plumes, which latter usually measure from 420 to 

 500 mm., and reach 100 millimeters or so beyond the end of the tail. 

 Since none of these differences is, however, entirely constant in 

 relation to either Casmerodius albus albus or Casmerodius albus 

 timoriensis, as a study of specimens shows, the American race 

 should stand as Casmerodius albus egrctta (Wilson). 



1 Birds of Australia, III, pt. 5, March 26, 1914, pp. 431-435. 



