138 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4tH SER. 
Puffinus tenuirostris (Temminck) : SLENDER-BILLED 
SHEARWATER 
Coves—WNectris tenutrostris, II, 126, 143; Nectris brevicauda, II, 127; 
N. brevicaudus, II, 143 
SaLtvin—Pufiinus tenuirostris, 370, 388. 
GopMAN—Puftinus tenuirostris, xiii, 149, pl. 39. 
As is well known, the Slender-billed Shearwater is a South- 
ern Hemisphere species that penetrates into Arctic regions in 
its exodus-migration. Offshore in the vicinity of Point Pinos, 
California, it has been found by Mr. Beck and other collectors 
to be rather common in November or December in some years, 
and in others, rare or apparently absent. Individuals have also 
been met with by Mr. Beck in October and January, his 
earliest record being a solitary specimen, taken October 13, 
1910, and his latest, a straggler taken January 30, 1908.* Ac- 
cording to Mr. Beck’s label, the ova in a female of December 
2 were functionally enlarged. It should be added, that this 
species has not been detected in spring and summer in the 
hosts of Sooty Shearwaters. 
The fact that the Slender-billed Shearwaters are late and 
irregular in their occurrence off Point Pinos is of peculiar in- 
terest, creating the doubt whether they are really returning 
migrants bound for South American breeding stations, or 
whether they are strays that have missed their way and, falling 
in with the rear guard of the Sooty Shearwaters, have come 
down the wrong coast, the American instead of the Asiatic. 
It is hoped that Mr. Beck’s explorations off the mainland of 
Chile will clear up the matter. 
No specimens of this species were brought back by the 
Academy’s Galapagos Expedition. 
Bicoloration in the Sooty Shearwater finds a counterpart in 
the Slender-billed. In extreme dark examples of the latter 
species the general aspect of the under coverts of the wings is 
gray; the feathers of the throat are superficially dark gray, be- 
coming pale gray beneath the surface. In extreme light ex- 
amples the general aspect of the under coverts of the wings is 
decidedly grayish white; the chin and anterior portions of the 
throat are likewise grayish white, sometimes mottled with 
1The record for “April 10” in Dr. Grinnell’s Distributional List of the Birds of 
California, p. 27, is a lapsus calami. 
