White-headed Duck fails to make grade for British list

White-headed Duck will remain on Category D of the British list following a review by of the species' status by the British Ornithologists' Union Records Committee (BOURC).

Species on Category D of the British list are those where 'there is reasonable doubt that they have occurred in Britain in a natural state'. This translates to birds in this category being untickable (birds are tickable on Categories A, B and C).

The BOURC undertook a lengthy analysis of British records, with the pattern and incidence of these compared with that in other western European countries where extralimital records have been deemed to be of wild origin, such as in France and the Netherlands.

 Belvide Reservoir, Staffordshire, was once a regular staging ground for moulting Ruddy Duck in early autumn and attracted White-headed Duck on occasion – including this juvenile in September 2003 (Steve Nuttall).

However, the BOURC's analysis revealed no obvious link between the pattern of British records and the expected pattern of occurrences of birds on the Continent and, thus, suggest it is hard to suggest any are definitively wild birds.

The BOURC agreed that the British records were likely a mixture of wild and escaped captive birds, but a consensus on identifying an individual bird that was wild was not achieved. Hence, the final BOURC vote on the status of White-headed Duck on the British List was split, with six for retention on Category D and four for Category A. Following BOURC procedures this majority vote resulted in a decision for Category D.

Records of White-headed Duck in the late 1990s and early 2000s, usually among sizeable Ruddy Duck gatherings, hinted that these were genuine migrants, moving up from Iberia with returning Ruddies (which would move from northern and western Europe to Iberia). A significant number of White-headed Duck popped up in 2002-03; at least two (and possibly four) in autumn 2002 saw up to three hang around into the following spring, with another apparent influx in the late summer and early autumn of 2003 seeing at least six, and possibly several more, appear.