222 Ridgway on the Eggs of the Caspian Tern. 
eggs having been covered by drifting sand. Comparatively few pairs 
had deposited their full complement, a large majority of the nests 
containing but a single egg. Still, more than five hundred nests 
were counted, while our man declared that not one third the num- 
ber of birds seen by him on his former visit were there, the greater 
part having been frightened away by the shots which he had fired at 
them two days before. The birds having in a few moments mounted 
out of gunshot, we passed on to the upper end of the island, in 
order to give them an opportunity to re-alight, as well as to ascer- 
tain what other species were in the vicinity. Now and then a 
Royal Tern passing at suitable distance, on its way back to the 
breeding-ground, afforded us an occasional shot ; and while waiting 
for such chances, as we stood upon a mud flat left bare by the ebb- 
tide, a peculiar hoarse snarling note caused us to look to the right, 
just in time to behold a Caspian Tern coming straight toward us, 
in a manner unmistakably showing that her nest was in the vicinity. 
Two shots fired at her in quick succession, but without effect, caused 
her to turn, when, flying directly back, she swooped several times 
over a particular spot on the sand near the beach, nearly an eighth 
of a mile distant. Concluding, from her actions, that she had 
young, we proceeded directly to the spot, and found, in a cavity 
scooped in the bare sand, a single egg, undoubtedly belonging to 
the bird in question, whose mate flew about at a respectful dis- 
tance. We did not again visit the nest until several days after, 
when it was found to contain two eggs, which we believe is all this 
species ordinarily lays, as seems also to be the case with the Royal 
Tern ; but we were again unsuccessful in obtaining either of the 
birds. 
The nest, like that described by Mr. Henshaw, and distant scarcely 
a hundred yards from it, was isolated from those of other birds, and 
was merely a slight hole scooped in the dry sand. The two eggs 
are altogether different in shape, texture, and markings from any 
eggs of the Royal Tern we have ever seen, and could readily be 
picked from five hundred or more of the latter, embracing all the 
numerous variations. They measure respectively 2.75 x 1.90 and 
2.70 x 1.85, the larger one about equally rounded at both ends, the 
smaller more pointed at one end than the other, but yet not ap- 
proaching the distinctly pointed form characteristic of nearly all 
eggs of the Royal Tern. The surface is much smoother than that 
of the egg of the Royal Tern, and the shell harder. The ground- 
