no 



THE OSPREY. 



Literature. 



dw1ght on the sequence of pl.tmages 

 \m> Moults of the Passerine Birds of 

 New Yokk.t — In this paper of ovei" 270 pages. 

 Dr. Dwight has produced a notable work, far 

 more important for the science of orn ithology 

 than all the systematic work of a year past. 

 It deals with many of the problems of feather 

 change in a fairly satisfactory way. and pre- 

 sents a detailed study of the sequence of feather 

 change of all the passerine birds found about 

 New York. Seven photographic enlargements 

 of various structural features of feathers add 

 greatly to its value. Preliminary sections treat 

 of the Fundamental Principles, Determination 

 of Age by Osteological Characters, Wear or 

 Feather Disintegration, Protective Sequence in 

 Feather Loss, Advance of Moult in the Feather 

 Tracts. Early Plumages and Moults of Young 

 Birds. Sequences of Plumages and Moults, Color 

 Facts us. Color Theories, Outdoor Study of 

 Moult, Migration of Young" in Autumn, Classifi- 

 cation of Moult, and the bulk of the paper. Des- 

 cription of Species and their Moults. A copious 

 bibliography of the general subject completes a 

 masterly paper. Dr. Dwight's work has been 

 so favorably received in the '". Ink" for January 

 1901, by Mr. Witmer Stone whose few criticisms 

 have been commented on by the author in the 

 April "Auk" that it is unnecessary here to fol- 

 low in the same strain. 



The present reviewer having trodden indepen- 

 dently for many years past along many of the 

 paths pictured by the author will endeavour to 

 point out in no captious spirit, a number of in- 

 stances whet" Dr. Dwight's rulings seem some- 

 what unhappy. The three very distinct com- 

 parative plumages of birds, the Neossoptile. 

 Mesoptile niu] Teleoptile are not mentioned, but 

 instead we tind 1. Natal; 2. Juvenal; 3. First 

 Winter; 4. First Nuptual; 5, Second or Adult 

 Winter; 6, Second or Adult Nuptual. The cor- 

 responding moults are 1, Postnatal; 2. Posjuve- 

 nal; 3, First Prenuptual. 4, First Postnuptual; 

 5. Second or Adult Prenuptual; 6, Second or 

 Adult Postnuptual. These somewhat cumber- 

 some terms have already produced misunder- 

 standings and seem in practice to be unwieldy, 

 and even when comparatively used unscientific. 

 Thus the juvenal (mesoptile) plumage of the 

 Hooded Warbler, to use for instance an extreme 

 case, produced and worn for but for a few days 

 is comparative with the mesoptile plumage of 

 the cormorant which is at once the juvenal, first 

 winter, spring, and second summer plumage. 

 Therefore, the Postjuvenal moult of the warbler 

 occurs in the month in which it was hatched, 

 while in the cormorant the similar fact occurs 

 twelve months after hatching. The First Nup- 

 tual plumage of a given bird means one thing' 

 definitely, while the corresponding dress of 

 another species may mean something- quite 

 different. Again, the Prenuplual moult in a 

 certain species means one definite thing, while 

 in another it occurs at an entirely different time 

 or may be absent: in part of one species it may 



occur in August, in another in our spring, and 

 yet. in another while the bird is breeding. 



In species wintering in the summer of South 

 America it would seem incongruous there to say 

 that such a bird is in its first "winter" plumage 

 when the time is summer, and the birds expe- 

 rience nothing of a winter. Terms should be 

 cosmopolitan. The "winter" plumage of the 

 Scarlet Tanager. for instance, is a fiction, a 

 nonbreeding plumage is meant. Our author 

 evidently feels some doubt as to the sufficiency 

 of his terms for he tells us on page 1114. "Wear 

 with its abrasion and fading often takes the 

 place wholly or in part of a prenuptual moult. 

 modifying in marked degree either the first 

 winter or the adult winter dress. Consequently 

 the plumage to which I would restrict the name 

 nuptual may be acquired by moult, by wear or 

 by both, and it is not the true breeding" plu- 

 mage," etc. Of course the word plumage in this 

 extract and in much of the paper really means 

 plumage condition, quite a different thing. < lur 

 author truly says, "The breeding- plumage, then, 

 on which descriptions of species are based does 

 not, in very many cases, represent the highets 

 plumage of the species; it may be a mixture of 

 several and all of them badly worn." It is evi- 

 dent then that the word plumage has a double 

 meaning- and that our systematists have many 

 sins to answer for. The subject is a very diffi- 

 cult and complex one. and needs treatment from 

 many points of view before the true solution is 

 evolved. 



In the formative stage of a nomenclature of 

 feather terms it is perhaps necessary to use 

 makeshifts, and for our author's purpose in com- 

 paring chronological feather conditions of the 

 different species it is very useful, but the impor- 

 tance of the subject demands a better classifica- 

 tion. 



The term "Natal down," or natal plumage is 

 unfortunate. The conditions at hatching and 

 even for some time after are, comparatively, so 

 different in different groups of birds as to render 

 such terms misplaced when speaking of some 

 buds. It is unfortunate that our author did not 

 use terms to tit similar comparative conditions 

 of all birds. 



In his treatment of the species Dr. Dwight is 

 very satisfactory each sequence of plumage con- 

 dition being treated independently. It is unfor- 

 tunate, however, that so many "Natal downs" 

 are recorded as "no specimen seen" for many of 

 these could have been obtained. 



Without specimens or notes at hand, packed 

 preliminary to a long journey, it has not been 

 possible to verify all of Dr. Dwig-fit's conclu- 

 sions, but the following occur to mind. In the 

 Maryland Yellow-throat a complete molt of the 

 mesoptiles occurs in the late summer, and this 

 is probably true also of the Vireos tho' the 

 Doctor states the contrary. The numerous crows 

 with molting flight feathers seen in spring and 

 early summer show the last change on the pre- 

 vious summers birds, in fact, it seems probable 



tAnnals N. Y Acad. Sci. Vol. XIII. Oct ::i lmiu. 



