Isla de Lobos, Peru

Lobos de Tierra is a Peruvian island 19 km from the mainland. It is about 10 km long and 3 km wide

In 1863 the island was estimated to have guano deposits of almost 7 million metric tons, which were then exploited without any control. Today that wealth has almost disappeared and the little remaining guano does not have the same quality as before. The climate of this island is very warm and is home to birds like Kelp gulls, boobies (Blue-footed, Nazca, and Peruvian), and Guanay cormorants. The last two species were of great importance during the heyday of guano. The ideal type of guano is found in exceptionally dry climates, as rainwater vapourises and leaches nitrogen-containing ammonia from guano. In order to support large colonies of marine birds and the fish they feed on, these islands must be adjacent to regions of intense marine upwelling, such as those along the eastern boundaries of the Pacific and South Atlantic Oceans.

Interestingly The Guano Era refers to a period of stability and prosperity in Peru during the mid-19th century. It was sustained on the substantial revenues generated by the export of guano and the strong leadership of president Ramón Castilla. The starting date for the guano era is considered to be 1845, the year in which Castilla started his first administration. It ended shortly after the war between Spain and Peru in 1866.

Guano (via Spanish, ultimately from the Quechua wanu) is the excrement of seabirds. As a manure, guano is a highly effective fertilizer due to its exceptionally high content of nitrogen, phosphate and potassium: nutrients essential for plant growth. The 19th-century guano trade played a pivotal role in the development of modern input-intensive farming practices and inspired the formal human colonization of remote bird islands in many parts of the world. During the twentieth century, guano-producing birds became an important target of conservation programs and influenced the development of environmental consciousness. Today, guano is increasingly sought after by organic farmers.

Seabird guano consists of nitrogen-rich ammonium oxalate and urate, phosphates, as well as some earth salts and impurities. Unleached guano from favoured locales, such as the islands off the coast of Peru, typically contains 8 to 16 percent nitrogen (the majority of which is uric acid), 8 to 12 percent equivalent phosphoric acid, and 2 to 3 percent equivalent potash.

At that time, massive deposits of guano existed on some islands, in some cases more than 50 m deep. Bizarrely the United States passed the Guano Islands Act in 1856, which gave U.S. citizens discovering a source of guano on an unclaimed island exclusive rights to the deposits. Whenever any citizen of the United States discovers a deposit of guano on any island, rock, or key, not within the lawful jurisdiction of any other Government, and not occupied by the citizens of any other Government, and takes peaceable possession thereof, and occupies the same, such island, rock, or key may, at the discretion of the President, be considered as appertaining to the United States. More than 100 islands have been claimed for the U.S. under the Guano Islands Act. Most are no longer considered United States territory; those remaining under U.S. claim are:

Control over guano played a central role in the Chincha Islands War (1864–1866) between Spain and a Peruvian-Chilean alliance. Indentured workers from China played an important role in guano harvest. The first group of 79 Chinese workers arrived in Peru in 1849; by the time the trade ended a quarter of a century later, over 100,000 of their fellow countrymen had been imported.

Since 1909, when the Peruvian government took over guano extraction, the industry has relied on production by living populations of marine birds. U.S. ornithologists Robert Cushman Murphy and William Vogt promoted the Peruvian industry internationally as a supreme example of wildlife conservation, while also drawing attention to its vulnerability to the El Niño phenomenon. The importance of guano deposits to agriculture faded after 1909 when Fritz Haber developed the Haber-Bosch process of industrial nitrogen fixation, which today generates the ammonia-based fertilizer responsible for sustaining an estimated one-third of the Earth's population.

From 1840 to 1880 annual production of guano average around 500,000 tons per year, which steadily dropped to 48,000 tons by 1910 and 11,000 tons by 1920. It is difficult to obtain today's figures, as the government seems a bit coy about releasing figures. Academics on the web put it at about 10.000 to 30,000 tons per year. Although islands are left fallow for up to 10 years before being stripped again, guano is not accumulating as it has done in the past.

DNA testing has suggested that new potato varieties imported alongside Peruvian seabird guano in 1842 brought a virulent strain of potato blight that began the Irish Potato Famine.

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The Isla de Lobos was in fact more memorable for its Blue Footed Boobies, than for Sea Lions, The remains of a once flourishing guano industry with abandoned buildings and an extensive network of railway lines was photogenic.

Blue-footed boobies belong to the genus Sula, which comprises six species of boobies. It is easily recognizable by its distinctive bright blue feet, which is a sexually selected trait. Males display their feet in an elaborate mating ritual by lifting their feet up and down while strutting before the female. The female is slightly larger than the male and can measure up to 90 cm long with a wingspan of up to 1.5 m. It can be found from the Gulf of California down along the western coasts of Central and South America down to Peru. Approximately one half of all breeding pairs nest on the Galápagos Islands.Its diet mainly consists of fish, which it obtains by diving and sometimes swimming underwater in search of its prey. While it sometimes hunts alone, the blue-footed booby mainly hunts in groups. It usually lays one to three eggs at a time. The species practices asynchronous hatching, which means that eggs that are laid first are hatched before the consequent eggs, resulting in a growth inequality and size disparity between siblings. This results in facultative siblicide in times of food scarcity.

The blue colour of the blue-footed booby's webbed feet comes from carotenoid pigments obtained from its diet of fresh fish. Carotenoids act as antioxidants and stimulants for the blue-footed booby's immune function, suggesting that carotenoid-pigmentation is an indicator of an individual's immunological state. Blue feet also indicate the current health condition of a booby. Boobies who were experimentally food-deprived for forty-eight hours experienced a decrease in foot brightness due to a reduction in the amount of lipids and lipoproteins that are used to absorb and transport carotenoids. Thus, the feet are rapid and honest indicators of a booby's current level of nourishment. As blue feet are signals that reliably indicate the immunological and health condition of a booby, colouration is favoured through sexual selection.

On to Huaca Luna

The voyage on Silversea Explorer in South America