Accumulated excrement and remains of birds, bats, and seals, valued as fertilizer. Bird guano comes mainly from islands off the coasts of Peru, Baja California, and Africa that are heavily populated by cormorants, pelicans, and gannets. Bat guano is found in caves throughout the world, and seal guano has accumulated to great depths on islands off northwestern Peru; both are lower in fertilizer value than bird guano.
This entry comes from Encyclopædia Britannica Concise.
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