22 CALIFORNIA ACADEMY OF SCIENCES {[Proc. 4TH Ser. 
IIT 
MIGRATION? 
WHILE the literature of ornithology abounds in references 
to the albatrosses and petrels as ocean wanderers, but little has 
been said of them as birds of passage, although they exem- 
plify every cardinal aspect of bird migration, including certain 
phases that are wanting in birds whose lives are more inti- 
mately connected with the land. Some species are apparently 
stationary, never venturing far from their breeding stations; 
others perform migrations that stop short of the Equator; 
others still are transequatorial migrants; others, breeding in 
the Tropics and subtropics, migrate in a direction not towards, 
but away from the Equator, breaking all the time-honored 
book rules for bird migration. 
MIGRATION IN THE SOUTHERN HEMISPHERE 
The species of albatrosses and petrels breeding in the 
Southern Hemisphere far outnumber those breeding in the 
Northern. Their migration, too, dwarfs the complementary 
migration of the northern species, and exhibits similar diver- 
sity in the direction and extent of the fly-lines. Among the 
longest are the transequatorial lines of the Sooty Shearwater 
and among the shortest is the line of the Snowy Petrel of 
Antarctic regions.” 
Transequatorial migration has often been misinterpreted. 
Even within the last three years a well-known writer upon the 
petrels has hinted that the nesting grounds of the Sooty Shear- 
waters visiting the ocean off California would ultimately be 
discovered north of the Equator.* The condition of the plum- 
1 Read in part at the thirty-third stated meeting of the American Ornithologists’ 
Union, held in San Francisco, May 18-20, 15. 
My former papers on bird migration were published as follows: 
‘ Auk, 1891, v. 8, pp. 50-55; 1892, v. 9, pp. 28-39; 1894, v. 11, pp. 26-35, 
4-1 
Bice Calif. Acad. Sci., 1895, 2d ser., Me ye pp. 179-210; 1896, v. 6, pp. 2-14; 1900, 
3d ser., Zool., v. 2, pp. 278- 316; pp. 350-3 
2 Cf. Wilson, Nat. Antarct. a N. i v. 2, Aves, pp. 90, 91. 
3 Mathews, Birds Austr., v. 98; cf. pp. 14, 90, 103. 
In the Ibis for July, 1915, an P88, 602, 603, 608, Messrs. Mathews and Iredale 
state positively that the Sooty Shearwater breeds on Pescadores Islands. Nevertheless, 
they offer no better evidence than the mere fact that among myriads of these shear- 
waters occurring in the Northern Hemisphere two individuals, with the base of the bill 
somewhat denuded+of feathers, were taken by a collector from holes during the month 
of May. It is well known that superannuated sea birds often retreat to the land and 
that a denuded state of the base of the bill is highly characteristic of such birds. 
