GEOGRAPHICAL SURVEYS WEST OF 100TH MERIDIAN. 331 
LARIDvE—Gulls, Terns. 
Larus Linmeus. 
L. californicm Lawr. California Gull. 
The present species is to be distinguished from the L. delawarensis, which it some¬ 
what closely resembles, by the following characters : 
L. californicm, adult—size larger; bill stouter; (wing, 15.43; tail, 6.24; bill, 1.82; 
depth above notch, .60; tarsus, 2.23).* 
Mantle dark pearl blue, much darker than in the succeeding. Color of bill (in fresh 
specimens, sometimes retained in skins) bright yellow, with an irregularly shaped spot of 
intense carmine near tip of lower mandible ; a spot or bar of black anterior to this on 
both mandibles. Iris hazel or brown ; tarsi and feet pale green. 
L. delawarensis, adult—size smaller; bill less robust; (wing, 14.40; tail, 6.06; bill, 
1.45; depth above nostril, .51; tarsus, 2.07).t 
Mantle pearl blue, always lighter than in. preceding Bill greenish yellow, encircled 
near tip by a broad black band. Iris light yellow ; tarsi and feet naples yellow. 
The amount of black on the bill of calif or nicus is variable. Usually it takes the form 
of spots or bars, as given above, but such is by no means always the case. Not rarely, 
as in several adult specimens before me, it appears in the form of a complete circle as 
in delawqrensis. In such cases, however, the ring is much narrower than in that bird. 
More rarely the black is almost or quite obsolete. Similarly, or even more variable, is 
the amount of white at tip of first primary. In a majority, perhaps, of specimens this 
is found as a terminal patch of about two inches in extent. Some individuals, how¬ 
ever, apparently perfectly adult, have the tip and shaft black for three-fourths of an 
inch, the white being restricted to a spot on either web above the black area, almost 
precisely as in delawarensis. Others, again, may have the extreme tip white, above 
■which is a band of black including both webs and the shaft, and giving way, higher 
up, to a second white area which mayor may not include the shaft; sometimes, iu- 
deed, the shaft, is black above and white below. Hence the spotting of the primaries 
and the black markings of the bill, points upon which considerable stress has been 
laid by some authors, are too inconstantto prove reliable guides in diagnosis, although 
not entirely without value. 
In fall the adults of either species have the white of head more or less spotted or 
streaked with dusky. The carmine spot on the bill of calif or nicus fades away, as also 
the crimson of eyelids and at augle of mouth, which is common to both species. The 
differences in size, especially of bills, and the color of the mantles may now be relied 
upon to separate them. To distinguish young birds, which always exhibit so much 
individual variation, becomes much more difficult, and I have found the size of bill to 
be the best and most constant feature. 
The Californian gull is found as a very abundant summer resident throughout the 
entire chain of lakes, and is, so far as I can learn, the only representative of the family 
present here at this season. Upon stretches of sand, jutting out from the little islands 
in mid-lake, or occasionally among the rocks along shore, this gull constructs its nest, 
and deposits from two to four eggs about the middle of May. The nest is a somewhat 
rude and bulky structure, particularly if it chances to be placed in rocky interstices, 
and is composed of weeds, sticks, and similar coarse material gathered from the shores, 
and lined more or less substantially with finer gleanings. 
The colonies are, as a rule, very large, one that I visited on Pyramid Lake contain¬ 
ing several hundred pairs, and the nests occupy every available spot on the sands. 
Unfortunately for the gulls, the eggs are rich and sufficiently well flavored to be a 
welcome addition to the meager fare of the settler, and hence, when accessible, are 
eagerly sought for. The colony alluded to above had been visited every few days for 
a period of more than three weeks, and every nest rifled. But so tenaciously do the 
birds cling to a spot that has once been chosen as a nesting ground that many still 
continued to deposit eggs, sometimes in newly-constructed nests, but often in the 
plundered ones. Many of the females had laid so often that the coloring pigment had 
been exhausted, and, as a consequence, a considerable portion of the later eggs were 
almost unspotted. The eggs of this gull are so nearly like those of the ring-bill as to 
be practically indistinguishable, although they average a trifle larger. In the exact 
style and amount of markings they vary interminably. 
L. delawarensis (Ord.). Ring-bill Gull. 
Given by Captain Bendire as a “common summer resident” of Malheur Lake, Oreg. 
It is possible that a mistake has been made here, and that the statement really applies 
only to the A. californicm. If correct it furnishes us with the only instance of the bird 
breeding within the United States. Upon all the. other lakes in California and Nevada 
* Average of four specimens. 
t Average of eight specimens. 
