234 BULLETIN UNITED STATES GEOLOGICAL SUEVEY. 



talis Aud. and A. wUrdeinanni Baird, and as probably affording addi- 

 tional evidence of their identity, it is desirable, after having disposed of 

 Dichromanassa rufa, to call Florida ccerulea into the case. It has, up to 

 the present time, been supposed that in this species the adult was invaria- 

 bly blue, while the young was as constantly white. This, however, 

 is not the case. I have recently examined a number of specimens of 

 this species in the white plumage, which possessed, in full develop- 

 ment, the ornamental plumes of the adult. This proves that the species 

 is, in a measure, dichromatic ; but in its dichromatism it differs from 

 others of the family in these remarkable respects: I have yet to see a 

 specimen in the white plumage, whether young or adult, (and I have 

 carefully examined dozens), which did not, in addition to the bluish tips 

 to the outer primaries, show more or less of a tinge of this color on 

 other parts of the plumage, particularly on the top of the head, which 

 usually, if not always, is tinged with a faint pearl-blue wash, — some- 

 times exceedingly faint and delicate, but apparently always present. On 

 the other hand, I have never seen a specimen in the blue plumage which was 

 not unmistakably an adult! It would therefore seem that while this 

 species is rarely if ever blue in its first plumage, some individuals only 

 partially assume the blue livery, while others remain white through lifei 



Kow, as to Ardea occidentalis and the so-called A. wiirdemanni: — In 

 his description of the latter. Professor Baird called attention to the 

 extreme similarity of these two presumed species, in general dimensions 

 and proportions, particularly of the bill, although at the same time, fol- 

 lowing Bonaparte, he placed them in different genera, — remarking at 

 the same time, however, that they did not seem to him separable by 

 sufficient characters. Later authors, with few exceptions (mostly those 

 who have observed the bird in nature), have referred it to A. herodias, 

 either as simply a particular plumage of that species or as an abnormal 

 variation. Professor Baird has himself suggested the possibility of its 

 being a hybrid between A. occidentalis and A. herodias. 



The bird named A. wiirdemanni appears to be much less known 

 than the white A. occidentalis, hence we may infer that the white plum- 

 age is the rule, and the colored plumage the exception. Audubon found 

 his A. occidentalis in immense numbers amongst the keys and mangrove- 

 lined shores of South Florida, but he was entirely ignorant of the exist- 

 ence of A. wiirdemanni. Even subsequent observers in Florida have 

 found the latter to be exceedingly rare, if, indeed, they discovered it at 

 all. As long ago as 1864, however, it was well known as a Jamaican 

 bird to Mr. Thomas H. March, who thus writes of it in his "Notes on 

 the Birds of Jamaica", published in the Proceedings of the Academy of 

 Natural Sciences (1864, p. 64): — 



" 275. Ardea wiirdemannii f — The White-crowned Heron is in the upper 

 plumage very like the preceding [A. herodias], but has the crown and 

 occipital elongated feathers white; the under parts white, streaked with 

 black; the breast bluish black, with bluish gray or ashy on the sides. 



