Cormorants and Fish One of the commoner sights on the
Amazon or its great tributary the Rio Negro is the fishing performance of the cormorants. Now the rivers are full of fish of any sort or size. Some may be 400 lbs. in weight, some are tiny and almost finless, some are so sharp-toothed and fierce that they tear in pieces and swallow any creature, including man, that invades their region. There are perhaps thousands of species. At any rate it is reported of one man of science who went out to investigate, that he had to stop when he had recorded )co species. One fish, of moderate size, that seems to be a favourite with the cormorants has a sharp upright spine on its back. When the birds catch one of these they laboriously chew at this spine with their beaks until it is reduced to pulp and then, and not till then, they take their meal. The river gulls, which are numerous, sometimes attempt to mob the cormorants, but less successfully than the cormorants mob One another. An unsuccessful fisher will on occasion charge from the - depths into a more fdrtunate companion who is preparing his meal on the surface ; and the bump may make him drop his fish to the robber's benefit. Fish-robbing is of course not an uncommon practice. The skua gull does it habitually. The eagle will rob the fish-hawk, and I know of one instance in which a pair of black-ba-ked gulls so assiduously mobbed a seal as it came to the surface that at last it dropped the fish, which was at once carried off by the birds. I have
myself seen a black-backed gull charge a flying heron and knock it into the sea, but in this instance the heron itself, not a captured fish, was the apparent object of the attack.
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