May, 1920 EXISTENCE OF SEA BIRDS RELATIVELY SAFE 103 
or became incapacitated for normal existence. For instance the finding of 
the remains of Horned Puffins on the sea beach of San Mateo County, as has 
recently been reported, should not at all be construed as constituting valid 
proof of the normal occurrence of this species off the Californian coast. The 
floating bodies may have been carried on the southward-moving off-shore 
‘‘Japan current’’ from off the coast of Oregon or even from Washington or 
Alaska. An element of chance clearly enters here which renders such ‘‘ree- 
ords’’ inconclusive. They certainly should not be considered as constituting 
the definite addition of a species to the existing native fauna of California, any 
more than with species imported by man. 
It may be properly pointed out further that because of their slow breeding 
rate, In other words their lesser powers of recuperation when their numbers 
have been unusually reduced, any new danger is much more likely to lead to 
serious consequences with sea birds than with land birds. Such man-caused 
factors as disturbance of nesting grounds, and oil on the water, might quickly 
lead to extermination of the pelagic birds affected, because wholly new in the 
phylogenetic history of the species. Rate of reproduction is a very conserva- 
tive character of species, not such as can be changed abruptly, as suddenly 
arising demands might make necessary to the continuance of the race. 
California Museum of Vertebrate Zoology, Berkeley, March 15, 1920. 
A RETURN TO THE DAKOTA LAKE REGION 
By FLORENCE MERRIAM BAILEY 
LAST DAYS IN NORTH DAKOTA 
(Concluded from page 72) 
HE last of August, having visited four lakes, I returned to the homelike 
farmhouse on North Sweetwater where I had explored sloughs and lis- 
tened to the joyful songs of the Sora in June; and with the exception of 
the automobile trip to Island Lake, stayed there until the first Geese came 
from the north the last of September. During the five weeks of my absence, 
the nesting season had been completed except for birds that raise several 
broods, such as my small friend the House Wren down at Stony Point, who met 
me with her habitual vigorous scolding explained by a late brood of fuzzy- 
headed soft-gaped and short-tailed youngsters. As late as the first of Septem- 
ber, the family were still met with, and talked volubly as I passed. Another 
mother with nearly grown young—a Holboell Grebe—was seen down by the 
lake shore the last of August, and I was much pleased to add her to my North 
Sweetwater list. 
In June a few pairs of Bobolinks had been seattered over my beat, the 
black and white males singing from the fence posts and on the wing; but in 
August the twang of their call note, heard occasionally from a telephone wire, 
made me look for the yellowish breast of the sparrowy looking bird overhead. 
Along the margin of the lake, a Red-tailed Hawk, perhaps having exhausted 
