Humboldt penguin
The historical breeding grounds for the Humboldt penguin were guano layers which covered islands of the Peruvian and northerly Chilean coasts in which the birds could burrow. The guano, a rich fertiliser and source of income for the Peruvian Government, and eggs of the Humboldt penguin were regularly sought after. The birds were also frequently killed by fishermen and guano workers for their oil and skin. The decline of the Humboldt penguin population is attributed to the harvest of guano in the 1800s, which led to the destruction of breeding grounds and to human disturbance.