780 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
All the eggs of this tern were fresh. We ate many of them while on the island and found them 
superior to those of the. domestic fowl. Mr. Schlemmer informed us that the egg of the albatross is 
the finest of all. 
The eggs of the sooty tern vary much in markings, but can usually be told from those of Sterna 
lunata by greater size and usually coarser spotting. The ground color is white or occasionally a cream 
buff. One type of marking consists of deep burnt sienna and grayish vinaceous spots, with occasional 
nearly black scrawls scattered rather evenly over the whole surface. These spots are 1, 2, and 3 mm. 
in diameter, with occasional larger and smaller ones. Another less prevalent variation consists of 
heavy, very deep burnt sienna blotches (5 mm. to 15 mm. in extent) congregated in a zone near the 
blunt end, and lesser pale grayish vinaceous and deep burnt sienna spots sparsely scattered over the 
rest of the egg. A very handsome type has the brown laid over the vinaceous, and occasionally the 
deep burnt sienna or chestnut shading off to one side into light, caused by the spiral twisting of 
the egg in the oviduct, a One specimen shows this to a marked degree, having long chestnut daubs 
extending spirally from the big end . b Still another type has fine brown and grayish vinaceous 
maculations scattered all over the egg, but more numerous at the blunt end. An abnormal specimen 
s entirely without markings, being pure white. The shape is ovate, either elongate or thick. An 
average specimen measures 53 mm. by 35 mm. 
This species has been found on Midway and Lisiansky islands, and we encountered numbers 
off the French Frigate Shoals, where in 1891 Henry Palmer found large breeding colonies. On 
Necker it is the most abundant tern, and as noisy as ever. The birds lay their eggs on the shelves of 
rocks where there is some soil and matted succulent portulacas. Unlike those on Laysan, all the 
eggs were advanced in incubation, and many young birds were hatched and peeping. Some were 
perhaps a week or 10 days old. A few eggs of this species were laid in cavities in the face of the 
rocks, where the young were eminently able to cling with their sharp little claws. They pecked 
most savagely if we attempted to dislodge them. Likewise many eggs were laid out on the bare rock 
in the full glare of the sun, and I saw a few perilously near high-water mark, in fact wet with spray. 
A number of eggs of Gygis were in this position also. Dr. Gilbert found a nest with two eggs, and saw 
the bird rise from them. The usual number is, of course, only one. 
The rocks where we did most of the collecting faced, a deep bay, and whenever the gun was 
discharged thousands of terns would simultaneously shoot out from the face of the crags, as though 
individually hit, filling the whole cove with an incredibly dense mass of angry birds. 
The species was abundant at Bird Island both in June and August. On our second trip we saw 
many in the spotted juvenal plumage. 
Saunders defines their wide distribution as follows: “Tropical and juxta- tropical seas, wherever 
suitable islands and reefs exist; occasionally wandering to Maine * * * and to Europe, even as 
far as England. Almost unknown on the South American side of the Pacific, otherwise very generally 
distributed.” c 
Sterna lunata. Gray-backed Tern. 
Sterna lunata Peale, U. S. Expl. Exp., Birds, 1848, p. 277. 
The gray-backed tern is one of the most characteristic birds of Laysan, and after Sterna fuliginosa 
is the most abundant of the five terns breeding on the island. Its habits are very similar to those of 
the sooty tern. The colonies of this species, as mentioned under Sterna fuliginosa, are somewhat 
peculiar in distribution. One large, rather scattered community encircles the island like a narrow 
band, close to the seabeach on the wind-swept sedgy slope facing the ocean and entirely outside the 
big colony of sooty terns. There are also some separated and small colonies in a similar position 
with reference to the lagoon. In short, there are two more or less interrupted circles of gray-backed 
terns, sandwiching between them a much greater community of Sterna fuliginosa. 
The single egg is laid on the sand, and in some cases on bare phosphate rock. A few young 
hatched while we were on the island, and all the eggs were advanced in incubation, whereas the eggs 
of Sterna fuliginosa were quite fresh, and many birds had not yet laid. The egg of this species is 
smaller than that of Sterna fuliginosa. No two specimens are alike, as is usually the case, I believe, 
with sea birds. The ground color is white or very pale yellowish, and the spottings a rich, often 
aGrinnell, Pacific Coast Avif. No. 1, Birds of the Kotzebue Sound Region, Alaska, p. 24. 
b Noted also by Snodgrass & Heller, Birds of Clipperton and Cocos Is., <Proc. Wash. Acad. Sci., iv, 1902, p. 507. 
«Cat. Birds Brit. Mus., xxv, p. 105. 
