118 
THE CONDOR 
Vol. XVI11 
It was in this colony that the piratical tendency of the gull was first 
observed. Owing to the proximity of our camp to the colony, the terns, which 
are shy birds, abandoned their nests. The gulls, which have little or no fear 
of man, and no compunction about egg stealing (of this we found ample evi- 
dence), raided this colony and destroyed a number of the eggs. The remainder 
were taken by our party as specimens, as it was evident that they would other- 
wise be destroyed. 
California and Ring-billed Gulls. — The nests of these birds were found in 
all parts of the island though they were the most plentiful on the beaches of the 
south and west sides. An idea of their abundance may be gained from figure 37, 
which ivas taken on the south beach. It is of interest to note that all the nest- 
ing birds are facing in one direction, the east. Nests were found on all parts of 
the island, from the beach within a feiv feet of the Avater to the top-most ledge 
in the crown of the Hat; from the sandy beach to the nooks and crannies of the 
rocks, and under the greasewoods ; two were even found in abandoned nests 
of the Great Blue Heron. They Avere in the parts of the island appropriated 
exclusively by themselves, and among the nesting colonies of the White Peli- 
cans and Great Blue Herons. For a description of the gulls’ nests reference 
may be made to the description of the nest of the Caspian Tern, with the addi- 
tion that those of the gulls were generally scantily lined Avith a feAv feathers 
and squirrel-tail grass. 
Very great diversity was seen in the individual eggs of different clutches. 
Some clutches Avere very light and sparsely mottled, others Avere almost entirely 
of a sooty brown color, the blotches coAmring the egg almost completely. A feAv 
had Avell defined streaks like the oriole’s or red-Avinged blackbird’s. One of 
the clutches was entirely different from the usual type in being blue in color 
and almost entirely unmarked. This can probably he explained by assuming 
some abnormal condition of the gland or duct that secretes the pigment, thus 
preventing the floAV of the brown coloring matter Avith which the eggs are 
normally blotched. The eggs were a very pointed oval in outline and uniform 
in size. 
The clutches were practically completed at the time of our visit (May 16) 
and usually contained three eggs. Occasionally tAvo and rarely four were 
found. Only in exceptional cases were young gulls found and these Avere but 
a day or so old. Figure 38 sIioavs one of these cases. The protective colora- 
tion of the young is here Avell shown by the likeness of the small elongated 
dots and background to the lights and shadows under Amgetation. A query, 
however, might be interposed, for the light and shadow scheme is reversed 
in the bird, that is, the background on the gull is light while with the sur- 
roundings it is dark. 
An interesting condition Avas noted among the gulls that might be called 
involuntary parasitism. Several clutches Avere found with one egg that varied 
greatly in its markings from the other two. At first this was accounted for by 
assuming that the parent bird deposited an egg that simply varied in its mark- 
ings from the other tAvo. Finally, however, there seemed to be so many of 
these cases that another explanation was sought, and what Ave believed to be 
the key to the true explanation was found in the presence of another clutch 
near by, with the identical markings of the odd egg in the first clutch. We 
concluded, therefore, that the second gull had mistaken her neighbor’s nest 
