Migrating through the Centuries

The Fratercula arctica, a seabird known also as the Atlantic puffin, can be found in the North Atlantic and Arctic regions. It spends the winter in the open ocean and is rarely if ever seen from land, but very recently hundreds of dead Atlantic puffins are washing up on the Portuguese coasts.

The Atlantic puffin is particularly sensitive to pollution and climate changes. It is only one of many marine animals on the red list of endangered species that are affected by global changes of anthropogenic origin. This case highlights the importance of analyzing nautical documents to retrieve data about the historical distribution of animals and plants in oceanic habitats.

Rutters and logbooks, especially, are significant documents in such research. The presence of certain bird species in specific navigation areas, for example, was systematically recorded by pilots. In Manuel Álvares’ seaman’s book (ca. 1545), we can find mentions of “feijões", small birds that resemble magpies, when approaching the Tristan da Cunha islands, while different birds are present near the Cape of Good Hope, such as albatrosses, black cormorants with white beaks, and some gulls that have black wing tips. Between Tristan da Cunha Islands and the Cape of Good Hope, the pilot observed the presence of monk seals (but never in June, “since they take shelter from the cold on land”, the pilot noted).

Monk seals, another endangered species, were also sighted by the pilot Manuel Mesquita Perestrelo in the same waters. In his rutter (ca. 1575), Perestrelo wrote about “an innumerable multitude of monk seals, some of them of incredible size.”

Working as unintentional ecologists, sailors left us precious records that today help scientists to understand the correlation between species and climate change, thus contributing to biodiversity conservation. [Luana Giurgevich and Silvana Munzi]