Ross's Goose added to Category A of British list


The British Ornithologists' Union Records Committee (BOURC) has announced that Ross's Goose has been added to Category A of its British list.

More than 50 years after it was first seen, the adult Ross's Goose at Plex Moss, Lancashire, has been recognised as a British first. Found on 5 December 1970, it lingered there until 17 January 1971 and was then seen again in consecutive winters to January 1974.

Ross's Goose had previously been placed in Category D of the British list for many years due to uncertainties surrounding the origins of birds found in Britain. The species is kept widely in captivity, with escapes known to occur.

However, it is a long-distance migrant in North America and there is much precedent for Nearctic wildfowl, including geese, to cross the Atlantic naturally and be found in Europe. Furthermore, the very significant growth and expansion of the Ross's Goose population since the 1950s has increased the probability of such transatlantic vagrancy.

In Britain, Ross's Goose is often recorded among Pink-footed Geese – as with this individual seen at several Scottish sites in recent weeks (Alex Shepherd).

Content continues after advertisements

Part of the BOURC remit and procedure is to periodically re-examine species in Category D. Following published BOURC guidelines created to judge the status of wildfowl (British Birds 113: 46-53), BOURC considered a number of records of Ross's Geese.

Following these criteria, the Plex Moss bird was found by the majority of the Committee (7:1) to be eligible for Category A. This record occurred during a period of rapid population growth of the species, and in circumstances highly suggestive of wild origin. Another important part of the process was to confirm the identification of this 50-year old record on the basis of the original field notes along with photographs. These documents were located and BOURC decided unanimously that the identification was secure.

Ross's Goose breeds in northern Canada and migrates to winter in southern and western USA and northern Mexico. A dramatic population increase has occurred over the past 40 years, with more than 2 million individuals now in existence and the species classified as Least Concern.

Ross's Goose should be placed after Cackling Goose on the British list, which now stands at 628 species (Category A = 610; Category B = 8; Category C = 10).