Monday, 3 January 2011

Apparent Nordic Jackdaws in Edinburgh and Galway

My interest in the Nordic form (Corvus monedula monedula) of the Eurasian Jackdaw was rekindled in March 2010 when a bird with apparent 'headlamps' walked past my car in Straiton, Edinburgh. After fumbling with my mobile phone, I managed this poor photo of it disappearing into a fenced-off construction area before then taking flight. I returned with proper camera gear several times but did not see the bird again. I was disappointed as my only shot of the bird failed to show any of its distinctive headlamp-like neck collar, though the bird may be identifiable as the pale nape is apparent.

After reading up on the identification of this form, the following papers seemed to be most useful: Rudy Offereins Dutch Birding article and a translation of an Ornithomedia page. The conclusions tend to be that the most distinct birds are identifiable, but that various intergrade forms exist.

While these papers are useful at helping define the characteristics to look for in the field, a recent mtDNA analysis of the corvids by Haring et al (2007) gives us further food for thought about the degree of genetic separation of these different subspecies. While the study showed a clear split between the Jackdaw and Daurian Jackdaw as good species, there was no clear separation of the Western, Nordic and Eastern Eurasian Jackdaw subspecies lineages. This, of course, supports the field observations of intergrading between the populations.

This autumn and winter I have kept an eye out for possible Nordic birds. A passage bird on Fair Isle was too distant to be seen closely and most of the birds that I have seen around Edinburgh seem very shy or very clearly spermologus.

The following birds seen in the Hermitage in Edinburgh in late November may well be Nordic monedula or intergrades between the Western spermologus and monedula - an intermediate form that has been termed turrium. Unfortunately the views were too tantalisingly brief to be conclusive. In particular I could not be absolutely certain that I could make out the scaled underparts, a feature thought to be restricted to the Nordic form.

After so little success I was surprised to be treated to extended views at close range of birds with clear neck collars at Nimmo's Pier in Galway on 28 December. I was not expecting to see birds with these non-Western characteristics so far west in Europe! First a pair of birds on the Claddagh green fed close by before being spooked by a dog walker and then a single bird came to take bread from the slipway at dusk. These birds look like turrium type Nordic-Western intergrades perhaps? Perhaps I'll get another look at them in spring when they head back through the East of Scotland and back to Scandinavia...

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