CORMORANTS 
Such is the cormorant’s aptitude for catching fish that Chinese and Japanese 
fishermen tether them to their boats with strings and employ them in place 
of hook and line. A ring around the bird’s neck prevents it from swallowing 
the larger catch. As soon as one fish is removed from its beak, the cor¬ 
morant dives after another. A cormorant kept in the London zoo lived 
twenty-three years. 
At liberty these large blackish-green birds fly in V formation. They 
are often seen swimming easily on the surface of the water and are also 
able to pursue their prey for some distance underwater, using both their 
wings and their webbed feet as paddles. They have been found in traps as 
much as forty feet below the water’s surface. Cormorants are very active 
birds and dive and plunge energetically all day long. 
Cormorants have rapid digestion and a phenomenal appetite, eating 
as much as half their weight each day. Fishermen have from time to time 
accused them of eating all the available salmon or other fish at certain 
localities, but investigation showed that they rarely eat fish palatable to man. 
These aquatic birds breed in spring, usually on the narow ledges of 
high cliffs. The female seems to take the initiative in courtship. The male 
toys with the nesting material, then passes it to the female who utters the 
mating call while arranging it. She then spreads her tail like a fan and 
bends it forward; she shuffles her wings and stretches out her head upside 
down along her back, swinging it from side to side. The male puffs out the 
plumage on his head and neck, and blows up his neck sac. Both birds hold 
their beaks wide open. 
Some species of cormorants are of great economic importance to man 
as producers of guano, found chiefly on the coastal islands of Peru and 
other parts of western South America. Guano or bird dung is valuable as 
a fertilizer and has a high nitrate yield. 
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