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August in south Shetland

Brutal but beautiful: juvenile GBBG (with Shag), Shetland

Barley still stands in the fields where colourful groups of Rock Doves congregate, while wader migration is under way.

Some of the breeding seabirds, especially terns and skuas, have already departed after another poor season.

As yet there has been little passerine migration, but that will change. After a long lull, the garden list is creeping towards 100 – still a long way behind some which have reached a remarkable 200!

Barley, Toab 

Crossbill taxonomy

Juvenile (Common) Crossbill, Shetland

In his 1937 ‘Monographic Study of the Red Crossbill’, Ludlow Griscom devoted 209 pages to the subject. Although he lacked field experience of old world taxa, he examined 546 specimens (compared with 2447 specimens from the new world). Amongst other findings, he considered that ‘specific’ characters between curvirostra (Common Crossbill) and pytyopsittacus (Parrot Crossbill) are completely bridged by the intermediate characters of crossbills in other geographic areas. He also considered that differences between the ‘white-winged’ crossbills were racial rather than specific (but see below). It is of note that he did not find any wing-barred (Common) Crossbills in the new world, whereas they are regularly recorded in the old world.

It is interesting to compare Griscom’s findings with a recent mtDNA-based phylogeny of crossbills (constructed by Laurent Raty) which can be found attached to post 200 here: http://www.birdforum.net/showthread.php?t=338168&page=8 The phylogeny does not show distinct genetic differences between curvirostra and pytyopsittacus (or for that matter scotica), though the sampled specimens of pytyopsittacus did not come from what is considered to be the core range of that taxon. It does however show distinct genetic differences between new world and old world (Common) Crossbills, and between bifasciata (Two-barred) and leucoptera (White-winged). It is not unusual for there to be genetic differences between new world and old world sister taxa, which are consequently treated as species rather than subspecies.

In our 2007 paper (https://britishbirds.co.uk/article/britains-first-two-barred-crossbill/ ), we described morphological and vocal differences between leucoptera and bifasciata which are now supported by genetic differences. It would therefore be reasonable to treat ‘White-winged’ and Two-barred’ Crossbills as species. They are certainly as or more distinct than other crossbill taxa currently treated as species.

Eagle Clarke – master of migration

The advance of spring (from Clarke 1912)

In his two volumes of ‘Studies in Bird Migration’ (1912), Eagle Clarke published the results of groundwork – 47 weeks in lighthouses and a lightship, and 14 weeks on St Kilda and Ushant – which established foundations for much subsequent work on migration through Britain. In the process he discovered Fair Isle, amongst others, and immediately recognised it as a site of outstanding importance. Those who have visited even a few of the sites explored by Clarke will know that they remain relatively inaccessible and require sustained physical effort to ensure reasonably complete recording. For example, a team of three wardens covers Fair Isle each day during the migration periods, which makes Clarke’s discoveries all the more impressive.

Amongst other things, Clarke was interested in the effects of climate and weather patterns on bird migration. It is reassuring that, despite the impact of climate change, the patterns he described a century ago (for example, the progression of migration during the spring) are much the same today. What has significantly changed is the volume of migration: the numbers of many species are now a fraction of what they were.

From the perspective of the age of the selfie, it is notable that nowhere in Clarke’s work will you find a photograph of himself. As Ticehurst put it in his appreciation in ‘Ibis’, published following Clarke’s death in 1938:
To his friends he was a very genial and lovable man, ever willing to help those who were keenly interested in ornithology, and a very great gentleman in all senses of the word. But he had no use for the dilettante or “pot-boiler,” and the only thing which would raise his ire and show that his tongue could be caustic on occasions was anything which savoured of humbug or of advertisement. 

Foula: the present in the past

Springs, Foula: my wife’s grandfather’s mother lived here

Foula has been less obviously affected by change than some other parts of Shetland, which probably makes human occupation hard but has benefits for wildlife.

Famed for its seabirds, especially skuas, it was the abundance of Snipe which I shall remember best. I have seen an estimate of about 100 breeding pairs, but would not be surprised if this is too low. They seemed omnipresent, and I even had the privilege of seeing an adult leading two peat-coloured chicks along the edge of the meadow behind the house.

During our stay we were lucky to see some migrants, including 2 Marsh Warblers, Icterine Warbler, and best of all a female Black-headed Bunting. Also of note was a presumed Lesser Black-backed x Herring Gull hybrid.

Snipe, Foula
Last but not least – Black-headed Bunting

Halligarth

Halligarth today

Most of this information is derived from J Laughton Johnston’s ‘Victorians 60 Degrees North’ (2007), which is fascinating but sometimes hard to follow.

Laurence Edmonston and his family moved into Halligarth in autumn 1832. It was he who planted the walled area of trees which now form the woodland by the house. His son Tom was encouraged to take an interest in natural history, and in 1834 at the age of nine was directed towards botany in particular. Young Tom quickly learned the local plants, helped by a list which his father Laurence had made.

In 1837, Tom discovered two small flowering plants on the slopes of Nikka Vord which he could not identify. A chance visit by one of the sons of the eminent botanist W J Hooker led to the identification of one of Tom’s finds as Arctic Sandwort, not previously known from Britain, and the publication of Tom’s catalogue of plants (compiled when he was just 11). Tom made other significant discoveries around Nikka Vord and on the Keen of Hamar, including Northern Rock-cress and most famously Shetland Mouse-ear (Edmonston’s Chickweed).

The woodland planted by Laurence remains, but the house is now in poor condition. There are plans for restoration headed by the National Trust for Scotland, but these will require significant investment. It would be a shame if we were to lose such an important part of Shetland’s natural history.

Halligarth as seen by Henry Saxby in the 19th century