THE DOUBLE- CRESTED CORMORANT. 
13 
propagation duties are over, both sexes are thin, worn, and unfit 
for human food. In this condition they pass down stream under 
the name of kelts to be rejuvenated in salt water and made 
ready for successive breeding migrations in following years. It 
seems to be yet an open question as to whether the kelt feeds 
in fresh water. General opinion indicates that they may do so, 
but definite data on the subject are difficult to obtain. If they 
do it must be at the expense of their own race — the parr, smolt, 
and perhaps grilse. It is evident, then, that the salmon have to 
run the gauntlet of their enemies in the estuaries once as smolts, 
twice as grilse, and again annually as long as they breed as 
salmon and kelt. The grilse are large enough to be practically 
safe from attack by cormorants except, possibly, the smallest and 
weakest whose weeding out is beneficial to the race. The salmon 
and kelt are obviously beyond danger from birds. There 
remains then, only the parr and smolt that have anything to 
fear from cormorants and these only as they are making the 
passage from fresh into salt water. The work has shown that 
during July and August either there are no smolt in the tidal 
mouths of the rivers or else the cormorants do not catch them. 
Though it is difficult to get exact data on the subject it seems, 
from the information at hand, that the journeying of the smolt 
to the sea is not accomplished in one general migratory move- 
ment but that they drift out continually during the summer 
months and that July and August conditions are fairly typical 
of the whole spring and summer season. If this is correct, the 
cormorants must be acquitted of any serious injury to salmon; 
if it is not, evidence to the contrary must be submitted. The 
food eaten by any species is governed largely, within certain more 
or less widely defined lines, by its availability. Cormorants 
probably eat practically any small fish they can catch, but any 
hunter knows that only one kind of game can be successfully 
hunted at a time: the hunter after deer rarely sees birds; the 
collector of ground birds misses the species over-head, and so on. 
Concentration in one direction blinds us to what is happening 
elsewhere. Occasionally the unlooked for does appear; but it 
is generally more or less of an accident and does not negative 
the foregoing rule. Hence creatures of prey hunting for bottom 
