628 LARUS AEGENTATUS, HERRING GTILL. 



The characters afforded liy the markings of the primaries— and especially of their 

 bases — have been usually disregarded or lightly passed over by some in the preparation 

 of diagnoses. Others, myself probably included, have inclined to lay too much strees 

 upon these features, which are to b« found varying to a great degree in different exam- 

 ples of the same species, as a consequence of immaturity. Birds of this family may be 

 of full size, possessing powers of reproduction, before they have attained the ultimate, 

 and then unvarying, picture of the primaries. Take a case susceptible of demonstra- 

 tion. Mr. Lawrence describes californicus as having the white apical spac9 on the first 

 primary crossed by a black subterniinal bar. So it is in his type-specimen now lying 

 before me. But this expression does not characterize the adult of the species. If his 

 type had lived longer the subterminal bar would have broken in two, become iirst a 

 spot and then a mere scollop on each web, and finally disappeared, leaving the broad 

 white apical space on the first primary, which is characteristic of the species, as at- 

 te.sted by a multitude of specimens taken in the highest stage of spring plumage. 



It must also be borne in mind that the expression " immature " may also be applied 

 to the primaries themselves as well as to the age of the bird. For it is most probable 

 that at each successive moult, after the bird itself is fully adult, the new primaries, 

 when they first sprout, have a inelura somewhat different from that finally attained 

 when they are of full length; but the perfect feather has practically characteristics 

 often distinctive of species. 



Mr. Audubon always maintained an opinion of the continual variability of the pri- 

 maries : " From the examination of individuals of this species [" argeniatus "] it would 

 appear that little reliance can be placed on the markings of the quills as affording a 

 specific character" (B. X. Amer. vii, p. 169). Let us examiue the facts he adduces in 

 suijport of his views. He continues: " Four undoubted specimens of Lurus argentaius 

 now before me have a white spot, varying in length from one to two inches and includ- 

 ing both webs, near the end of the first quill. One has no spot on the second qnill. 

 Another has a spot on both webs of the second quill of one wing, and a smaller spot 

 on part of the inner web of the same quill of the other wing. The third has a very 

 small spot on part of tbe inner wel> of the same quill of both wings. The fourth has 

 a large circular spot on the inner web of that quill of both wings." Although these 

 paragraphs seem to indicate material discrepancies, yet such is not really the case. 

 The white subapicalspot on the first primary existed in all his specimens, only varying 

 somewhat in size; and tlie same is the case with the spot on the second primary, which 

 so often makes its appearance with increasing age, thongh in perhaps the majority of 

 specimens it is wanting. In all his specimens the differences were only in the minor 

 details of a certain pattern which was not departed from. 



In examining the Herring Gulls contained in all the large collections of the Eastern 

 United States I have met with two specimens — one in the Cambridge Museum, and the 

 other in Mr. Lawrence'6 private cabinet — which present the distinctive characters of 

 the European bird. They are smaller than the average of smilhaonianus, and have the 

 apex of the first primary broadly white. Prof. Baird's opinion on these specimens, in 

 ■which I coincide, is that they are probably stragglers from Europe. The fact that 

 these specimens could be distinguished under circumstances so prone to cause doubt 

 and confusion renders them quite the reverse of counter-arguments to the separation 

 of the two varieties. 



It was with some hesitation that I separated, some years since, the American from 

 the European Herring Gull, fully anticipating the adverse criticism which such a pro- 

 cedure would call forth. A recent and more thorough reexamination of the whole 

 subject confirms my general conclusions, thongh I by no means insist upon or even 

 admit specific distinction. Provided the specimens before me exhibit typically the 

 characters of the European bird, which there is no reason to doubt, certain slight dif- 

 ferences do exist almost throughout extensive series compared. These points are the 

 following : 



First. The American bird averages larger in all its dimensions than the European. 

 The difference in length of wing of the two averages froiu one to two inches. The 

 feet, including both tarsus and toes, are about half an inch longer and proportionally 

 stouter. The bill, especially, is longer and stouter, particularly at the base. 



Second. There is generally preserved, in adult birds, a somewhat different pattern of 

 coloration of the primaries. In that of Europe the first primary has a white terminal 

 space* two inches long ; the second primary a large, rounded, subter-minal white spot, 

 usually occupying both vanes. The first primary of the American bird usually has a 

 rounded white subapical spot on the first primary (much like that on the second 

 primary of the European), alnwt always separated from the white apex; and if a spot 

 is present on the second \ rimary, it is small. By these features together, the Ameri- 

 can bird may usually be recognized as a variety, which should not be wholly ignored. 



There is another consideration to be taken in connection with the points already 



* This is precisely as in caJifornicus ; and, as in the latter species, the feather when 

 imperfect has .-i uanow, transverse, subterminal bar of black, which gradually resolves 

 into two spots or scoUojis, and finally disappears. 



