“The Twite has the distinction of being the only European bird derived from the Tibetan fauna type.”
“Twites also breed in southwest and central Asia – at up to 3,500 m asl in Tibet – and it is supposed that the European relict populations became isolated during the retreat of the ice age (Voous 1960)”
“With subsequent climate warming, Twites in Europe followed the tundra north and became isolated.”