Northern rockhopper penguin been caused by a vicariant event caused by a shift in the position of the Subtropical Front during the mid-Pleistocene climate transition. Analysis of a part of a mitochondrial control region from a northern rockhopper penguin found on the Kerguelen Islands showed that it may have come from Gough Island, 6,000 km away, and that the southern and northern rockhoppers are genetically separate, though some individuals may disperse from their breeding colonies. Many taxonomists have yet to recognize the split, although some are beginning to do so. More than 99% of northern rockhoppers breed on Tristan da Cunha and Gough
What Bird is That? author Nick Earls' 1999 young adult novel "48 Shades of Brown". The 48 shades refers to the number of distinct browns used by Cayley to describe bird plumage colours. What Bird is That? What Bird is That? A Guide to the Birds of Australia is a book first published in 1931 by Angus & Robertson in Sydney. Authored and illustrated by Neville William Cayley, it was Australia’s first fully illustrated national field guide to birds, a function it served alone for nearly 40 years. In 1960 it was rated the all-time best seller in Australian natural history. "What Bird Is