When a rare goose or duck arrives in the UK, the first question asked by the birding world is whether or not it might be a captive escape. Accidental or not, these escapes do muddy the waters somewhat. When a Steller’s Eider appeared in Orkney last month, it was swiftly declared as a genuine vagrant: a wild bird off-course. There are so few in captivity, no more than hundreds. There are 30 accepted wild British records, although the true number of individual birds involved is around half that – some like the recent sighting, stay around for a while. It is therefore one of the most desired of all species on the British list among keen ‘listers’ or ‘twitchers’.
Smallest of the Eiders, Steller’s is monotypic - it is the sole member of its genus, Polysticta. Along with the other eiders, it is in the tribe Mergini; the sea ducks. It feeds by upending, much like a dabbling duck, but is also accomplished at diving.