In order to prevent it from swallowing the fish which it takes, each bird has a ring or ligature passed round its neck.
The Cormorant is a most voracious bird, swallowing a considerable weight of fish at a meal, and digesting them so rapidly that it is soon ready for another supply. Although it is essentially a marine bird, hunger often takes it inland, especially to places where there are lakes or large rivers.
While the ducks and teal and widgeons may be stationary on the pool, the cormorant is seen swimming to and fro, as if in quest of something. First raising his body nearly perpendicular, down he plunges into the deep, and, after staying there a considerable time, he is sure to bring up a fish, which he invariably swallows head foremost. Sometimes half an hour elapses before he can manage to accommodate a large eel quietly in his stomach.
You see him straining violently with repeated efforts to gulp it; and when you fancy that the slippery mouthful is successfully disposed of, all on a sudden the eel retrogrades upwards from its dismal sepulchre, struggling violently to escape. The cormorant swallows it again, and up again it comes, and shows its tail a foot or more out of its destroyer's mouth. At length, worn out with ineffectual writhings and slidings, the eel is gulped down into the cormorant's stomach for the last time, there to meet its dreaded and inevitable fate.
Mr. Fortune gives a very interesting account of the feeding of tame Cormorants in China. The birds preferred eels to all other food, and, in spite of the difficulty in swallowing the slippery and active creature, would not touch another fish as long as an eel was left. The bird is so completely at home in the water that it does not need, like the heron and other aquatic birds, to bring its prey ashore in order to swallow it, but can eat fish in the water as well as catch them. It always seizes the fish crosswise, and is therefore obliged to turn it before it can swallow the prey with the head downwards. Sometimes it contrives to turn the fish while still under water, but, if it should fail in so doing, it brings its prey to the surface, and shifts it about in its bill, making a series of little snatches at it until the head is in the right direction. When it seizes a very large fish, the bird shakes its prey just as a dog shakes a rat, and so disables it. It is said to eat its own weight of fish in a single day.
Sometimes, when it has been very successful or exceptionally hungry, it loads itself with food to such an extent that it becomes almost insensible during the process of digestion, and, although naturally a keen-eyed and wary bird, allows itself to be captured by hand.
The nest of the Cormorant is always upon a rocky ledge, and generally on a spot which is inaccessible except by practised climbers furnished with ropes, poles, hooks, and other appurtenances. Mr. Waterton mentions that when he descended the Raincliff, a precipice some four hundred feet in height, he saw numbers of the nests and eggs, but could not get at them except by swinging himself boldly off the face of the cliff, so as to be brought by the return swing into the recesses chosen by the birds.
The nests are mostly placed in close proximity to each other, and are made of sticks and seaweeds, and, as is usual with such nests, are very inartificially constructed. The eggs are of a greenish white on the outside, and green on the inside. When found in the nest, they are covered with a sort of chalky crust, so that the true colour is not perceptible until the crust is scraped off. Two to four eggs are generally laid in, or rather on, each nest. As may be imagined from the character of the birds' food, the odour of the nesting-place is most horrible.