Sept., 1914 
STATUS OF CERTAIN ISLAND FORMS OF SALPINCTES 
213 
though at least one writer (Willett, 1912, p. 101) has questioned its distinct- 
ness, it has received quite general recognition as a valid race. The subspecies 
was described from very worn adults, collected in May, no birds in fresh 
autumnal plumage being available. This want has now been filled by the 
loan of four September specimens from the Thayer collection, and I have 
consequently been able to make more satisfactory comparisons of island and 
mainland birds than has been done heretofore. 
The characters of 8. o. pulverius as given by Grinnell (1. c.), consist, as 
compared with 8. o. ohsoletus, of notably greater size of bill and feet, and 
peculiarly yellowish coloration; as given by Ridgway (1904, p. 649), of “larger 
and relatively stouter bill and much paler, more buffy coloration.” 
First, as regards the supposed color differences: Grinnell (1. c.) remarks 
that the “yellowish coloration may be due in part to the bleaching and 
abrasion of the plumage, but the character is, nevertheless, quite apparent 
when compared with mainland specimens in correspondingly worn plumage.” 
The ochraceous suffusion remarked upon is truly a conspicuous feature of San 
Nicolas Island birds in abraded summer plumage, and it is not apparent in 
any similarly worn examples from the neighboring mainland, but nevertheless 
it is merely an adventitious acquisition, and one that can not be regarded as a 
specific character. This despite the fact that it could probably be safely 
used in distinguishing midsummer birds ! In a similar manner four of the five 
adults of guadelonpensis at hand, collected in May, are more or less discol- 
ored with a reddish suffusion over the entire plumage. This also, it is safe 
to say, is the result of some peculiarity in surroundings acting directly upon 
the feathers, and not to be considered as an inherent character of the species. 
Four September specimens and one January bird from San Nicolas 
Island have been carefully compared with corresponding mainland spe- 
cimens, and I am unable to distinguish the slightest significant difference in 
color or pattern. Shade and markings of back, breast, flanks, under tail 
coverts, etc., have been considered separately, and while there is great varia- 
tion in all these features among birds from any region, I can find no tendency 
among the San Nicolas Island specimens toward the development of any 
distinctive color character. 
Second, as regards differences of size : As shown in the accompanying table 
of measurements, 8. o. pulverius as compared with the mainland 8. o. obsoletus, 
has a slightly greater average length of culmen. This difference in culmen 
length is, I believe, somewhat greater than appears in these tables, especially 
as regards the females, where, according to the figures, it is not very well 
marked. Of the six females used in the measurements, four were collected in 
September. They are in fresh winter plumage, but whether they are adults, 
a year or more old, or immatures of the previous spring, was not noted by the 
collector, and there is not now, of course, any way of telling. To ascertain 
something of the variation by age I measured a small series of mainland birds 
in first winter plumage, the age determined by condition of the skull, and 
found the length of culmen appreciably less than in others unquestionably 
adult. In September collecting many more immatures than adults are taken, 
and it may well be that most or all of the San Nicolas Island September 
birds at hand are immatures in first winter plumage. Thus, invaluable as 
they are for color comparisons, it is possible that these specimens are not to 
be relied upon to show the true character of the race as regards length of 
