BLACK-HEADED GULL. 655 
and tail, pur? white; the scapulars, wing-coverts, and whole upper 
parts, are of a fine blue ash color; the first five primaries are black 
towards their extremities; the secondaries are tipped largely with 
white, and almost all the primaries slightly ; the bend of the wing is 
white, and nearly three inches long ; the tail is almost even ; it consists 
of twelve feathers, and its coverts reach within an inch and a half of 
its tip; the wings extend two inches beyond the tail; a delicate blustr 
is perceivable on the breast and belly. 
The head of the female is of » dark dusky slate color; in other 
respects, she resembles the male. 
imperfect sub-terminal bur on the tail, point it out as a voung bird, most probably com- 
mencing its second spring. ‘U'he rest of its plumage conesponds with that of L. zonorhyn- 
chus, except that it wants the extreme white tips of ile quill feuthers, which, on the third 
and following ones, are very pi in L. zonorhynch It differs, however, remark- 
bly, in its bill being shorter, though considerubly stouter, than that of our Z. canus; and, 
like it, itis wax-yellow, with a bright yellow rictus and point. Its tarsus is nearly one third 
shorter than that of ZL. zonorhynchus. Many may be disposed to consider this and the pre- 
ecding as merely local varieties of L. canus ; and it might be urged, in support of this opin- 
ion, that there are considerable differences in the length and thickness of the bills of indi- 
viduals of the common and winter Gulls killed on the English coasts, which are usually refer- 
ied to L. canus. We have judged it advisable, however, to call the attention of ornithologists 
to these American birds, by giving them specitic names, Jeaving it to future observation to 
determine whether they ought to retain the rauk of epecies, or be considered as more 
vurieties.?? — RicHarp. 
In this place must be introduced the genus Leséris, or Skua, of which only one sp. 
cies was enumerated by Wilson in his list —the L. cuturactes, Iliger — the com- 
mon Skua Gull of British ornithologists. The Prince of Musignano mentions, in 
addition, the now well-known aspen aud British species, L. parasiticus and 
pomarinus ; another somewhat allied, but not yet well distinguished, L. Buffonii, 
Bojé ; and a fifth species is described as ucw inthe Northern Zoology, and is ded- 
icated to Dr. Richardson ~— L. Richurdsonii. It seems closely allied to L. Buffo- 
ii, but the distinctions yet want clearness and confirmation. It was found breed- 
ing in considerable numbers in the barren grounds, at a distance from the coast. 
The following are Bonaparte’s characters of L. Buffonii, by which itis alone knowu. 
‘ Lestris Buffonii, Bojé. Bill, one inch and a quarter from the front, straight, notched 
middle tail feathers, gradually tupering, narrow for several inches, ending in a point ; tar- 
sus, one inch and a half long, almost smooth. — Adult, brown; neck, and beneath, white, 
the former tinged with yellow. — Young, wholly brownish, 
“Arctic bird, Edw. pl. 148; Burr Pl. enl. 762. Lestris crepidata, Brehm.”? — Bo ve 
Syn. No. 306. 
And I add the observations of Mr. Swainson regarding L. Richarsonii : — 
“¢ Richardson’s Jager, whole plumage, brown ; two middle tail-feathers, abruptly acumi- 
nated ; tarsi, black, twenty-two lines long. e 
“¢ This specimen appears to us tobe in full and mature plumage; we cannot, therefore, 
view it as the young, or even as the female, of the Lestris Buffomii of Bojé, which we only 
know from the characters assigned to it by the Prince of Musignano. According to this 
account, the L. Buffonii has the bill an inch and a quarter long from the front ; ours is only 
an inch: the tarsi are described as almost smooth, whereas in ours they are particularly 
rough. The adult, as figured in plate 762 of the Pl. enl. has the chin, throat, and sides of 
the neck quite white ; but, in our bird, these parts are of the same pure and decided tint as 
that of the body, except that the ear-feathers, and a few lower down the neck, have a slight 
tinge of ochre.* The tarsi also, in both the plates cited by the Prince, are colored yellow . 
These differences, with the more important one exhibited in the feet, will not permit us 
to join these birds under one nume. Another distinction, which must not be overlooked, 13 
in the color of the feet. Edwards expressly says of his ¢ Arctic Bird,’ (pl. 149, which much 
more resembles ours than that figured on the plate immediately preceding,) that ‘the lrg- 
and toes are. all yellow ;’ whereas, in our bird, these members ure of a deep and shinies 
black ; while the hinder parts of the tarsi, toes, and connecting membrane, are particularly 
rough.”? — Sw. 
This Jager breeds in considerable numbers in the barren grounds, at a distance from ! 
coast. It feeds on shelly moliusewe, which are plentiful in the small lakes of the Fur Con: 
tries, and it harasses the Gulls in the same way with others of the genus. — Ep. 
* The rere color or uniform tint of the lower parts will not stand as characters in our native species ther 
rary coas.antly. — Ed. 
