28 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4TH SER. 
As is well known to the student of migration, water birds 
nesting in the Tropics and subtropics are inclined after breed- 
ing to invade outlying areas higher in latitude. Examples in 
other groups than the albatrosses and petrels are found in 
Xantus’s Murrelet, Heermann’s Gull, Elegant Tern, and Cali- 
fornia Brown Pelican. The Sooty Tern has even wandered 
as far north as Maine. With the North American Continent 
on the west and the Gulf Stream with its varied phenomena on 
the east, it would be no great feat for a Sooty Tern to wing its 
way over familiar waters intervening between Cape Hatteras 
and the nesting station on the Dry Tortugas. 
Since the above was written, Dr. Watson has published an- 
other extended paper on the homing of Noddy and Sooty 
Terns of the Dry Tortugas.* As in his first paper, his conclu- 
sions are reached without definite data concerning the distribu- 
tion and movements of these terns after the breeding season, 
and without any data whatsoever concerning the route fol- 
lowed by the captive birds after their liberation at various 
remote points on the Gulf of Mexico. The birds were liberated, 
and some of them arrived at their breeding station. Between 
these two events no observations were made, and therefore it 
was not determined what did, or did not, guide the birds in 
their return passage. The coast-line, the Gulf Stream, the 
great volume of fresh water that pours into the Gulf of Mexico 
from the Mississippi and other rivers, the temperature of the 
surface water inshore and offshore, the trade-winds, and the 
land- and sea-breezes are a part of the every day life of birds 
frequenting the Gulf of Mexico, and there is no evidence that 
these physical phenomena do not direct the birds in their local 
and migratory movements. Observance of birds actually 
migrating is the real key to how birds find their way. 
The evidence does not warrant the assumption that migra- 
tory birds are endowed with extraordinary faculties. The 
facts show that birds possess in an eminent degree the faculty 
to remember places and direction, that they have great visual 
powers, and that they keenly sense slight differences in tem- 
perature, and that migratory birds probably have in addition 
to these heritages an innate desire for travel (wanderlust).? 
TYP EeplDept, Mar! Riot Camm Tae Ween Sis eps co 
ane Proc. Calif. Acad. Sci., 2d ser., v. 6, p. 13, footnote; 3d ser., Zool., v. 2, 
p. 
