The marine wildlife of Dyer Island needs your support! Please donate today!

learn how you can be a part of our efforts to conserve and protect our environment and beautiful creatures



African Penguins are endemic to Southern Africa, occurring only in South Africa and Namibia where they breed mainly on offshore islands. The African penguin is classified as an endangered species by the International Union for Conservation of Nature.

On Dyer Island, the African Penguins would naturally burrow into the soft guano to nest. During the mid 1800’s and early 1900's however, the guano was removed from the island and sold as fertilizer. The penguins now struggle to burrow into the hard, rocky substrate on Dyer, and have been forced to nest on the surface, leaving their eggs and chicks exposed to predation by Kelp Gulls. CapeNature, in partnership with Dyer Island Cruises and the Dyer Island Conservation Trust, has embarked on a programme to introduce artificial nests on Dyer Island, providing extra shelter for breeding penguins.

There were about 4000 pairs of penguins breeding on Dyer Island in 1959. This number increased to 23 000 pairs in 1979 (55% of the Western Cape breeding population and the largest African Penguin Colony of all). Since then it has been declining, and in 2009 there were only an estimated 1200 breeding pairs.

Guano ('gwä-"no) - (n): a substance composed chiefly of the excrement of seafowl and used as a fertilizer; also : a similar substance (as bat excrement or cannery waste) especially when used for fertilizer.

The study of guano history requires review and analysis of 19th century law, sociology, geography, philosophy, biology, and agriculture. This curious intersection should be of particular interest to American academics. Guano, and its fascinating history, is illustrative of America's diverse composition and its often conflicted interests.

In the 19th century guano's pursuit was fueled by a desire for better crops. Farmers, particularly those working the tired fields of the Eastern Seaboard, discovered that scattered bird droppings dramatically increased crop production. This finding created a demand for guano all along the Atlantic Coast. Early guano was mined domestically from reserves in North Carolina and other Southern states. As the use of guano grew, agronomists sought to discover why it worked. Scientists opined that the value of guano depended on its potency. Different varieties of guano were deemed better than others, based on the amount of nitrates retained in the product. It was soon realized that guano mined from exceptionally dry climates, where rainwater had not run off the nitrates, was far better as a fertilizer than other, more diluted phosphates. Guano, an increasingly valuable commodity, might be discovered outside of the US, in certain areas that would be ideal for its creation. A series of investigative missions sought to locate areas where such super productive guano might be found.

Britain, a country not unfamiliar with exhausted and under productive fields, located reserves of guano in a series of islands off of Peru. The product was mined and returned to Britain via schooner. American scientists soon discovered that this Peruvian variety of guano was far superior to the American type, and that its use could dramatically increase productivity.

Although an excellent fertilizer, Peruvian guano came to America at a great expense. Competition for phosphates between British, American, and, increasingly, European farmers, encouraged the government of Peru to raise taxes on their newfound source of wealth. Understanding that the resource, and the profits from the trading thereof, were finite, the British sought a monopoly from Peru on the mining and export of guano. This preemptive move by the British forced the Americans into the role of customers. American farmers passionately objected to paying the Crown for Peruvian guano, and voiced their objections to Congress.

At the heart of their protests was the cost of imported guano. Congress attempted to address this issue through a series of economic and diplomatic strategies. None of these attempts succeeded. On the economic front, a series of tariffs and incentives failed to curtail the British and Peruvians.

© 2010 Dyer Island Conservation Trust