142 
THE CONDOR 
I VOL. V 
When a considerable number of cormorants had congregated they seemed to 
become suddenly animated by a common purpose and followed one another in 
swift flight to the foot of the rapids. There most of the assembled birds alighted 
and formed a line across a considerable section of the river. Then with flapping 
wings, beating the surface of the water into foam, the black line moved up stream, 
the birds showing much excitement but keeping their places very well. The sur- 
face of the water was churned to spray by the strokes of .so many powerful wings 
and feet, yet in the midst of the apparent confusion tlie birds could be seen darting 
to one side or the other, or spurting a few feet ahead of the line, and sometimes 
disappearing for a moment below the surface but nearly always securing a fish. 
When they reached the head of the rapids the birds flew heavily to their perching 
stones or swam slowly up the quiet surface of the river. After a short rest the 
YOUNG MEXICAN CORMORANT, LAKE CHAPALA, JAN. 5, 1903 
line would reform and again beat up the rapids and this was repeated until the 
birds had satisfied their hunger. 
The cormorants evidently fully appreciated the advantages of thus working in 
company, so that a fish trying to escape from one bird would almost certainly be- 
come the prey of another. The purpose of beating the surface of the water with 
their wings was evidently in order to alarm and confuse the fish so that they 
would dart blindly about and become more easily captured. I have seen parties 
of gannets doing the same thing in the midst of schools of fishes off the Tres 
Marias Islands. 
When the cormorants were gorged they deserted the fishing ground for the 
day and streamed back down the river to the lagoons where they perched motion- 
le.ss for hours in large mangroves or other trees along the edge of the water. 
