British Birding Association UK400 Club

See http://uk400clubrarebirdalert.blogspot.com/

 

With the arrival of 9 Two-barred Crossbills on Fair Isle this afternoon, a new record has been set. With 33 now recorded since the first on Orkney on 20 July, 2008 supercedes 1987 as the largest influx ever of this species in Britain. There have been just three such events in the past 50 years – with 25 birds in 1987, 24 in 1990 and 17 in 2002.

Back to the records - with today's 18 new arrivals, a total of 33 individuals have now reached the Northern Isles, including 11 on Shetland (Sandgarth on 28-29 July, East Voe, Scalloway, on 30 July, Esha Ness Lighthouse on 30 July to 3 August, Norwick, Unst, on 5 August, Tresta Links, Fetlar, on 6 and 6 at Sumburgh Head on 6) 13 on Fair Isle (female and juvenile on 27-31 July, with 4 present on 1 August and 1-2 until 5, with 9 in one flock on 6), 8 on Orkney (Evie on 20 July, Mull Head on 28 July, Stenness on 29-30 July, Queenamidda, Rendall, on 29 July to 1 August, Crafty, Finstown, on 29-30 July, Stronsay on 3 August and 2 on North Ronaldsay on 6 August) and one on St Kilda (3-4 August).

 

As for racial identification, I am assuming all of the British birds are bifasciata, presumably originating from Siberia. However, I am uncertain of any criteria separating Siberian birds from those in North America. Siberian birds are very slightly larger on average and have a slightly thinner bill, with some adult males being more uniform pinkish-red, often lacking the dark feather bases. Like all crossbills though, plumage is highly variable depending on age and time of year. Biometric data (based on relatively small samples) suggest New World birds are shorter-winged and shorter-billed, but I am not sure of the validity of this data.

 

If anyone is familiar with both forms (sub-species) and has found a way of readily separating them, I would be most grateful to hear from them.