422 LARIDZ. 
The nest is simply a depression in the soil, with a slight lining of dry grass. 
The eggs are olive-buff, with spots and small blotches of various shades of brown, 
sometimes collected near the larger end, with inconspicuous spots of pale underlying 
purple 1. 
4. Larus heermanni. 
Larus heermanni, Cass. Pr. Acad. Phil. 1852, p. 187*; Salv. Ibis, 1865, p. 190’; 1866, p. 198°; 
Sel. & Salv. P. Z. 8. 1871, p. 574°; Baird, Brewer, & Ridgway, Water-Birds N. Amer. ii. 
p. 252°; A.O. U. Check-l. N. Amer. Birds, 2nd ed. p. 20°; Saunders, Cat. Birds Brit. Mus. 
xxv. p. 2257; Nelson, N. Amer. Fauna, no. 14, p. 23°. 
Blasipus heermanni, Coues, Ibis, 1864, p. 388°; Lawr. Mem. Bost. Soc. N. H. ii. p. 317”. 
Supra schistaceus, alis saturatioribus, remigibus nigricantibus, primariis intimis anguste et secundariis 
latius grisescenti-albo terminatis; tectricibus primariorum extus grisescenti-albidis; supracaudalibus 
cineraceis ; cauda nigra, albo terminata; collo undique et corpore subtus pallide cineraceis, abdomine 
dilutiore; pileo, faciei lateribus et gutture toto albis; subalaribus et remigibus intus plumbescenti- 
brunneis, axillaribus cinerascentioribus: rostro rubro, nigro sepius terminato; pedibus nigris; iride 
brannescenti-grisea; annulo periophthalmico rubro. Long. tota circa 18°0, ale 14:0, caudee 5-4, 
culm. 2:0, tarsi 2°0. (Descr. maris adulti ex Monterey. Mus. Brit.) 
2 mari similis, sed paullo minor et rostro debiliore. 
Pul. hiem. ptilosi estive similis, sed pileo et facie laterali cum gutture imo grisescenti-fusco striolatis, gula 
tantum albida: rostro pallide rubro, nigro latius terminato. (Descr. femine adulta ex Santa Barbara. 
Mus. nostr.) 
Juv. Fuliginoso-brunneus, notei plumis plurimis pallidiore brunneo marginatis: subtus vix cinerascente 
lavatis. (Descr. avis jun. ex Chiapam. Mus. nostr.) 
Hab. Paciric Coast or Nortu America from British Columbia southward 67.—Mexico, 
coast of Western Mexico (Abert*), Mazatlan (Grayson !°), Isabel I., off San Blas 
(Grayson 1°, Nelson’), Tres Marias Is., Maria Cleofa I. (Welson®); GuatEMa.a, 
Pacific coast ?4, Chiapam 279, San José? (0. S.). 
This is a member of a small group which is restricted to the Pacific, and is, more- 
over, confined to the American side, with the exception of L. crassirostris of J apan and 
China. Heermann’s Gull occurs on the Pacific side of North America during the 
breeding-season, and migrates south along the Pacific coast of Central America as far as 
Chiapam in Guatemala, where Salvin met with some young birds on the shore and 
lagoons in January®. Grayson shot specimens of LZ. heermanni near Mazatlan in 
February and March, and considered it to be only a winter visitant!°; but he appears 
to have afterwards found it breeding, as an egg in the U.S. National Museum procured 
by him is recorded as being from that locality 5. 
Mr. E. W. Nelson met with two or three pairs on Isabel Island, and half a dozen 
others about the Tres Marias. He found a nest on May 30th, which had been occupied 
earlier in the season, on a rocky islet off the shore of Maria Cleofa, and full-grown 
young were also seen on the rocks. The old birds pursued the Blue-footed Gannets 
in pairs, and forced the latter to disgorge the fish they had captured. He remarks 
that the Gulls are bold and noisy aggressors when they wish to take advantage of 
