236 BULLETIN UNITED STATES GEOLOGICAL SUB.VEY. 



the true wiirdemanni, the writer being perfectly familiar with the char- 

 acters of the species, having many times handled the type-specimen. 

 Owing to the excitement of the moment, and perhaps also to the distance, 

 a shot at the bird as it flew was uneffectual j and the attempt of a friend, on 

 another occasion, to kill it (or another individual) under the same circum- 

 stances only resulted in severely wounding it, when it managed to reach 

 the opposite shore, where it alighted in the top of a tall dead tree upon 

 the bank of the river. During the past summer (June, 1877), the writer 

 visited the cypress-swamps about three miles from the scene of the 

 above, in order to determine, if possible, whether A. wUrdemanni was 

 to be found in the vicinity of a large colony of A. herodias, which had 

 been frequented for years by these birds. The result was unsatisfactory ; 

 for although one which was believed to be this species was shot at on 

 the wing and fatally wounded, it did not fall until so far from us that it 

 could not be found, although it was heard to crash through the branches 

 and strike heavily upon the ground. 



From the above it may be reasonably inferred that while the bird 

 known as Wiirdemann's Heron exists in very few collections, it is of 

 more frequent occurrence and wider distribution than has generally 

 been supposed. It is also equally probable that it is nothing more nor 

 less than the normal or colored phase of plumage of Ardea occidentalis 

 Aud. From what is known of the other species in which dichromatism 

 is apparent, it becomes evident that this condition is developed in a 

 peculiar way in almost every species. Thus, in Demiegretta sacra and 

 Dichromanassa rufa, individuals are white or colored, as the case may 

 be, from the nest up, while examples at all intermediate are excessively 

 rare. In Florida ccerulea, on the other hand, specimens to some degree 

 intermediate are very numerous ; it is also a peculiarity of this species 

 that it seems never to be blue in its first plumage, many individuals 

 which are white in youth changing to blue later in life, while others re- 

 tain through life the colors they first assumed ! Who, then, in view of 

 these facts can offer reasonable objection to the theory that Ardea occi- 

 dentalis is likewise represented by two distinct phases of plumage, of 

 which the white is by far the more common, the normal or colored 

 phase {^^ wurdemanni ") being very rare — perhaps becoming extinct ? I 

 am not aware that Herodias egretta is ever any color but pure white all 

 over ; nor have I ever seen a white specimen of Ardea herodias ; yet of 

 this latter species I have seen an example whose plumage was charac- 

 terized by the admixture of white feathers. Tbis circumstance may 

 have no more important significance than a mere individual tendency 

 to albinism ; but I am inclined to look upon it rather as denoting either 

 the dawn or close of an era of dichromatism — upon which the species 

 may be just now entering, or may have recently left. 



