OF NORTHERN ILLINOIS. 



521 



Iu this list only those families which are more or less peculiarly represented here have 

 received special notice ; several have been wholly passed over, on account of the incom- 

 pleteness of the observations and from there being nothing of special interest to present, 

 the species observed being those of known wide distribution. 



to the large white apical space on the first primary which exists birds "(see his "4th" difference), is wholly at variance with 



in the European bird; constantly, so far as I have opportunities the general law apparent in the changes in markings of this 



for judging. While the bird is undergoing the changes in- character; at least I am quite unable to recall a single corro- 



cident to its arriving at maturity, there are great and indeed borativecase. From his description of them, the four European 



endless variations in the precise character of the primaries, specimens examined by Dr. Coues were evidently very mature 



All, however, uniformly tend towards the same result, and in birds, 



fully adult birds these characters are constant." If the differences indicated by Dr. Coues' diagnoses of the 



In respect to the variation in size between American and American and European Herring Gulls had been constant, no 

 European birds alluded to, "amounting to nearly two inches" one would doubtless question their claims to specific diversity; 

 in the length of the wing, " and in none is it," he says, " less but among birds presenting variable characters, as in the 

 than half an inch," (see Dr. Coues' " 1st" difference,) 1 present case, it seems to me we cannot be too fully on our 

 have found a difference in a series of twenty Massachusetts guard in allowing such characters weight till we fully know the 

 birds fully as great ; between the two extremes it exceeded two amount of this variability, and have, if possible, obtained some 

 inches in the length of the wing, while one specimen from the clew to its cause and laws of change. While sincerely regret- 

 Atlantic coast of Europe is hardly so large as the average, ting that my convictions in this case lead me to expressions 

 The stoutness of the bill, as well as its form, vary correspond- of opinion at variance with those of so thorough and careful an 

 inglv, and in respect to the angle especially, which, as the ornithologist as my friend Dr. Coues, they are of course made 

 whole bill thickens with age, gradually becomes less acute, or only in a spirit of cordiality, and with the sole desire of advanc- 

 has a less "pointed and well-defined apex. (See Dr. Coues' ing truth, 

 distinction "2d.") I can hardly dismiss the subject without alluding to other 



In respect to the character of the markings of the prima- queries which my study of the Gulls has developed, one of 

 ries, there are two specimens in the La Fresnaye collection which is as to whether L. californicus Swain, is really distinct 

 of the Boston Society of Natural History, labelled " Lams from L. argentatus Briinn. or is based on very mature indi- 

 argentatus," the one from the Mediterranean ami the other viduals of the latter. In respect to their distribution, we find L. 

 undoubtedly from the Atlantic coast of Europe, which, with the argentatus (Smithsonianus Coues) ranging across the continent; 

 Museum of Comparative Zoology specimens, complete the series L. californicus, originally described by Lawrence from Califor- 

 of gradation between the typical L. Smithsonianus Coues and nia, comes not only from the Pacific Coast but from the interior 

 the L. argentatus Coues. One has the colors of the wing of North America, and from Arctic America generally; while 

 assumed to characterize invariably the European, and the the Beaufort specimen mentioned above comes very near, if 

 other is identical in this respect with the Beaufort speci- it be not actually identical with it. Larus argenlatoides of 

 men in the Museum of Comparative Zoology, in which (the both Bonaparte and Richardson is, as Dr. Coues observes, mi- 

 European) the subterminal white spot is separated from the doubtedly to be referred to it ; L. argenlatoides of Brehm 

 terminal by a band of black. In this connection particular seems alike referable to it, if we ignore its European locality; 

 attention is requested to the sentences we have italicized in the otherwise we must also recognize this form from both conti- 

 above quotations, and to the preceding description of the Amer- nents. Bonaparte also gives it as "common near New York 

 ican specimens in the Museum of Comparative Zoology. The and Philadelphia." The original specimen of californicus as 

 " notorious inconstancy" in the terminal markings of the wing described by Coues (1. c. p. 301), accords in the character of 

 above referred to as having been generally received as a fact, the wing-markings with my specimen from Beaufort. The 

 our own experience seems fully to confirm. Yet there is still resolving of the black bar on the first primary in the series 

 an evident law of change, which is simply an increase in the of specimens of californicus into "two little spots, then into a 

 size of the white markings of the wings, and in the general slight indentation at the edge of the feather, which finally 

 purity of color, with the increase of age, with a like modi fica- disappears altogether, leaving the apex of the first primary 

 tion in the thickness of the bill, and the outline below of the purely and uninterruptedly white for nearly two inches," as 

 lower mandible ; old birds having the largest amount of mentioned by Dr. Coues, is not only suggestive of its relation- 

 white on the first primary, and a subterminal white spot on ship to the true argentatus, but of the inconstancy ol this 

 the second, often of considerable size, while these decrease in character in a closely allied but supposed distinct species, 

 size in younger specimens till we miss them entirely in birds which is taken as the basis for the separation of " Smith- 

 of the first and second years. The black band across the tips sonianus " from argentatus. Upon the relationship of califor- 



of the primaries also increases, especially on the inner ones ; nictis to the European argentatus we find Dr. Cones 1 sell 



when first appearing being present on only the five or six saying, " If it be an error lo refer the argenlatoides of Rich- 

 outer, and afterwards reaching the seventh, and more rarely ardson to the californicus, or, in other words, if there be a 

 the eighth. Dr. Cones' opinion that the subterminal white true Herring Gull in the north with flesh-colored legs, / do 

 spots on the second primaries are characteristic of immature not k-noiv by what characters it could be separated from the true 

 birds, and are of particularly rare occurrence "in very old European argentatus" (1. c. 302). The different color of the 



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