92 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. 



Besides these places we found them breeding in scattered congregations all 

 along the rocky terrace west of the Jordan, from the shore to the highest points. 

 On the east, in addition to the rookery at Tower Point, we observed a dozen 

 isolated nests at Bull Head Point, near Arch Rock, and about half that number 

 right at the Weather Bureau observatory, where, rewarded for their confidence 

 in man, they brooded unmolested. The great mass of driftwood, thrown up by 

 winter storms, was a favorite spot in the Shell Beach ropkery. We did not, 

 however, observe any of these birds nesting off the main island. 



While they are somewhat wary, many allowed us to come quite close before 

 rising from their nests. The latter are placed in natural basinlike hollows 

 among the rocks, by which they are partially sheltered, although some were in 

 the most open and windy situations. The nest is a bulky structure, composed 

 of various dry island weeds and grasses, and has about as much claim to 

 ingenuity as those of most sea birds. They vary little in size,- averaging 13 

 inches across, the cavity being 8 inches by 4 deep. About many of them I 

 noticed small heaps of ejected fishbones. 



Mr. Brewster (1902) says of the nesting habits of this species in 

 the Cape Region of Lower California:, 



Mr. Frazar found a breeding colony of about 25 . pairs on a small rocky 

 island a little to the westward of Carmen Island. Most of the nests were only 

 just begun, and but ;two contained eggs, one set, however, comprising the full 

 complement of three. This was on March 13— a date about two months earlier 

 than that at which the first eggs are usually taken on the Farallon Islands near 

 San Francisco. The nest day another breeding ground was discovered on the 

 northern end of the island of Montserrat. Here some 50 pairs had congregated. 

 Few of their nests were finished and only eight contained eggs, the number in 

 each set varying from one to three. At both of the places just mentioned the 

 nests, which were made of seaweed, were built at the foot of the cliffs, just 

 above high-'water mark, and often in nooks or crevices. 



Although the nest may be frequently robbed and several sets of 

 eggs may be laid, only, one brood of young is raised in a season. The 

 normal set consists of three eggs, though two eggs often constitute 

 a full set in the later layings, and sometimes a single egg is incubated. 

 Sets of four eggs are rare. 



Eggs. — The eggs of the western gull can not be distinguished with 

 certainty from those of other gulls of similar size, and they are 

 subject to the usual variations. The ground, color is " buffy brown," 

 " tawny olive," " cinnamon buff," " deep olive buff," or " pale olive 

 buff." They are Usually heavily spotted, blotched, or scrawled, more 

 or less evenly, with " clove brown," " bister," " burnt umber," and 

 various lighter shades of brown, as well as various shades of " Quaker 

 drab " and " mouse gray." The measurements of 70 eggs, in various 

 collections, average 72.4 by 50.4 millimeters; the eggs showing the 

 four extremes measure 78 by 47, 73 by 53, 67.5 by 48 and 78 by 47 

 millimeters. 



Yotmg. — Mr. Emerson gives the period of incubation as 24 days. 

 He says that both sexes take turns at the duties of incubation, but 

 there are no set times for relieving each other. The bird which is 



