72 



REMARKS ON THE BITTERNS. 



By Edward Blyth. 



The comprehensive genus Ardea, as defined by Temminck, and adopted by 

 Mr. Jenyns in his Manual of British Vertebrate Animals, is exceeding difficult 

 to subdivide into minor groups, corresponding to the genera of other recent 

 systematists. To confine our attention to the few species admitted into the 

 British Fauna, the distribution of these into Herons, Bitterns, and Nightherons, 

 may appear sufficiently cogent, as the typical forms are mutually very distinct ; 

 but numerous exotic species connect these primary modifications of the same 

 type so intricately, that although in the present state of Ornithology their 

 separate recognition is absolutely requisite, it is impracticable to furnish respec- 

 tive definitions that should include all the species, and the only available method 

 of distinguishing them systematically is to indicate the prevalent distinctions of 

 the more characteristic species, the dividing lines — of whatever value we choose 

 to make the subordinate groups — being utterly arbitrary. Indeed, it is hardly 

 necessary to seek beyond the British (or, more properly speaking, British-killed J 

 species,' for exemplification of the futility of attempting dichotomous separation. 

 The Purple Heron, though otherwise a typical Ardea, has the toes and long 

 claws of a Bittern ; as has also the Buff-backed Heron or Egret (Ardea-egretta 

 russata), the short and comparatively weak bill of which, I have little doubt, 

 will sooner or later induce somebody to make a separate division of it. Boje 

 has already indicated A. ralloides, Auct., and some allied species, under the 

 designation Buphus, and the Prince of Musignano has distinguished the tiny 

 Dwarf-bitterns by the term Ardeola; the former having been variously posited, 

 by different writers, as Herons or Bitterns ; and the latter, also, grouped with 

 the Bitterns by Mr. Selby, whereas Mr. Jenyns deems them to be more imme- 

 diately related to the true Ardece. Again, the Cayenne Nightheron (Yellow- 

 crowned Heron of Wilson) deviates considerably from the type of Nycticorax, 

 approximating the Boatbills (Cancroma) ; which latter are physiologically as 

 closely allied to the rest of the group as are either of the previously specified 

 divisions. Save the American and European Bitterns, therefore, and the greater 

 and smaller European white Egrets, not two of the various species which have 

 occurred in Britain are subgenerically altogether identical. Still it is only when 

 a numerous suite of foreign species are placed in juxta-position, that the nullity 

 of what many consider to be satisfactory separations becomes palpably apparent. 



On the other hand, however, the entire group (comprising the Boatbills, of 

 which the beak, as stated by Cuvier, is simply that of a Heron or Bittern, very 

 much flattened and inflated) is as thoroughly distinct from all other groups, even 

 the most allied — which is that of the Storks and Adjutants — as can well be ; 



