FOULA HERITAGE
Foula - The Edge of the World
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FOULA HERITAGE
Foula - The Edge of the World
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Foula 1924-37 Telegraph Installation Foula 1936 The Edge of the World Red-throated Diver or Rain Goose
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FOULA FIELD MOUSE Foula has a subspecies of Field Mouse with the name Apodemus sylvaticus thuleo. This is one of three distinct subspecies in Shetland, with another twelve subspecies in the islands of western Scotland. This is a recognized biological oddity because the Field Mouse is very constant over its whole range from China westwards. For a long time biologists sought to explain this through the idea of land bridges. Hence the theory that Field Mice got to Shetland over a land bridge from Orkney. This bridge being later severed, as were bridges from Shetland to Fair Isle and Foula. The resultant isolation of these separated populations was thought to have led to their evolving into distinct subspecies. The problem with this theory is that geologists no longer think that, since the last ice-age, there could have been such land bridges to the Outer Hebrides or Shetland. So how did the Field Mice get to these islands? In his book, Inheritance and Natural History, Professor R. J. Berry takes a different approach to this question. He examines the genetic make-up of these different subspecies and asks which populations most closely resemble each other. It turns out that the Field Mice of Shetland are genetically closer to the Field Mice of Norway than they are to those of Britain. As he puts it “In population language the Scottish island mice are ‘Viking’ mice (Berry, 1970b).” He believes that the founders of the Field Mice in the main Shetland archipelago came direct from Norway in the Viking longships, and that the founders of the Field Mice of Fair Isle and Foula came from Shetland. Their distinctness being due to the smallness of the genetic pool in the first few founding members. The Field Mice of the main Shetland archipelago are typified by those in Yell Apodemus sylvaticus granti. They are intermediate in size to the other two subspecies and always have a dark breast spot. The Fair Isle Field Mouse (A. s. fridariensis) is the largest subspecies and occasionally has a few dark breast hairs. The Foula Field Mouse (A. s. thuleo) is the smallest but has the largest hind feet and normally no trace of a breast spot.
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