Science: Guano Sanctuary

It started even before the Incas. Ever since, Peruvians have cherished the 40 million sea birds whose droppings make high-grade fertilizer (guano) for Peruvian farmers. In Inca days, the penalty for molesting the birds was death. Now the protection of the guano birds (cormorants, boobies and pelicans) is the care of the semi-official Compaia Administradora del Guano, set up in 1909 to develop the country's evil-smelling guano deposits.

The Guano Co.'s armed guards patrol the small islands off Peru, where most of the birds live, protecting them against human egg robbers as well as against their natural enemies: vultures and condors. The islands' cliffs have been topped with walls to make the birds take off at a sharp rate of climb instead of trailing their feet and knocking precious guano into the water. Passing ships are prohibited from blowing their whistles, for even a brief toot will scare the birds into the air, where they mill in black clouds wasting their guano on the sea.

Thanks to such tender care, the birds have multiplied mightily. In 1909 the annual guano crop was only 77,000 tons. Last year the protected birds turned out 240,800 tons (worth nearly $14,850,000). But the fight to make Peru secure for guano birds is ceaseless. Off the coast, cold water wells up from the bottom of the sea bringing nutrients that support vast shoals of fish on which the guano birds feed. Sometimes a shift of wind or ocean currents brings warm water to their islands. Then the fish disappear, and the birds starve.

When the warm, water came in 1891 and again in 1925, it had disastrous effects on the guano birds. Millions migrated to southern Peru; finding few islands to roost on, they took to the dangerous land, where they fell prey to all sorts of land-based enemies.

This year the cycle of disaster threatened the birds again. The sea grew warm and fish scarce. Streams of hungry birds ribboned down the coast. But this time they found sanctuary: "artificial islands" that the good Guano Co. had made for them by building walls across promontories. The birds can roost on them, safe from land enemies, and the cold sea around them swarms with fish.

Last week the migration was proceeding with hardly a casualty. Some 20 million guano birds are already established in their new quarters. Peruvians hope they will stay there permanently, out of reach of the warm-water cycle, and repay the thoughtful company with guano.