Yellow-browed Warblers breed across Russia, extending east from the Urals as far as Kamchatka and south to Afghanistan, northern India and the Sea of Japan. In the northern Urals, their breeding range is just inside the boundary of the Western Palearctic, but every autumn they appear well inside the region in seemingly ever-increasing numbers.
In autumn most of the breeding population probably migrates through north-eastern China, filtering down to the species’ winter quarters, which extend from central Nepal south to the Malay Peninsula. The breeding zone is vacated in August and September and birds arrive in the winter range from mid-October, departing again in late March and early April.
The middle fortnight of October is the peak time for Yellow-broweds’ arrival in Britain, but the first birds often turn up as early as mid-September and the last as late as November. Records in England are mostly along the east coast south to Norfolk and along the south coast from Kent to Scilly. A few birds are recorded inland or from western counties. The east is usally the first area to see the new arrivals, with southern and south-western counties getting their first Yellow-broweds a few days later.
In Scotland, the Northern Isles and east coast sites get most of the records, but the species also reaches the Outer Hebrides in most years. In Wales, most records come from Bardsey Island, and the highest numbers usually coincide with major arrivals on the east coast. In Ireland, most Yellow-broweds are seen in the counties of Cork, Waterford and Wexford, with Cape Clear, Co Cork, recording the largest influxes, with at least 50 in 1985.
In the 1970s the average number occurring annually was 76, but in the 1980s and 1990s it rose to 320. 1988 was a record year with 739 recorded, while in 2003 there were more than 500. Both totals were eclipsed in the autumn of 2005, however. October of that year saw a huge arrival on the east coast, with record day counts at many sites: up to 24 at Spurn Point, 18 at Flamborough Head and 14 at Whitby, all in Yorkshire; 12 on Fair Isle, Shetland; 11 on Holy Island, Northumberland; 11 at Reculver, Kent; and 11 at St Abb’s Head, Borders. There were also 13 on Cape Clear and 10 at Mizen Head, Co Cork. In Scotland, at least 360 were reported, with more than 170 on Shetland and Fair Isle. The total recorded in Britain for October 2005 was at least 1,250, 75 of which reached Ireland.
Wintering birds are becoming more common, perhaps due to themild winters that Britain now experiences. In 2006-07 there were birds along the south coast from West Sussex to Cornwall – and some stayed well into April.
So why do so many Yellow-browed Warblers reach Britain each autumn? Many theories have been proposed, including reverse migration, genetic mutation and natural dispersal. What is not in dispute is that the records of Yellow-browed (and related species such as Pallas’s Warbler) have increased more than could be due to the growth in the number of birders.
Yellow-browed Warblers have now been seen in most European countries, as well as in North Africa and the Middle East. In September 1987one was even trapped in Senegal. The fact that regular records are now spread across Europe and into the Middle East suggests some kind of dispersal on a broad front.
Perhaps we are witnessing a subtle shift in wintering range, with regular dispersal having become successful and leading to overwintering and a subsequent return migration. Maybe the birds we are seeing have become genetically programmed to migrate this way, with Britain and Europe now on a new migration path and a new winter range slowly evolving. Whatever the reason, there is no doubt that this warbler, one of our smallest scarce visitors, is welcome whenever it appears.
How to find
The best chances of finding long-distance wanderers from Siberia come when the prevailing autumn winds are from the east or north-east. Yellow-broweds are most likely to appear when high pressure over Scandinavia causes winds to blow across the North Sea to the east coast of Scotland and England.
Coastal woodlands are the best place to check, especially if they include trees that attract insects, such as Sycamores. Yellow-browed Warblers are very active birds, flicking though the branches and hovering to pick off a choice insect, and they are often found quite high in the canopy. Wait patiently and scan the trees for movement – sometimes they will join tit flocks and roam through the trees with them. Always listen carefully, as a Yellow-browed’s call-note is a loud and distinctive tsoeest, often providing the first clue to its presence.
Where to watch
The sites listed below regularly record Yellow-browed Warblers and have been selected to offer a geographical spread.
- Northumberland: Holy Island (NU 130430)
- Cleveland: Hartlepool Headland (NZ 530340
- North Yorkshire: Filey (TA 120815)
- East Yorkshire: Spurn Point (TA 419148
- Lincolnshire: Gibraltar Point (TF 556580)
- Norfolk: Holkham Pines (TF 880452)
- Norfolk: Wells Woods (TF 910455)
- Norfolk: Stiffkey Woods (TF 964439)
- Norfolk: Great Yarmouth Cemetery (TG 527083)
- Suffolk: Lowestoft Denes (TM 552945)
- Essex: The Naze (TM 264233)
- Kent: St Margaret’s at Cliffe (TR 368444)
- East Sussex: Beachy Head (TV 583954)
- Dorset: Hengistbury Head (SZ 173908)
- Dorset: Portland Bill (SY 681689)
- Devon: Start Point (SX 820357)
- Cornwall: Isles of Scilly (SV 915110)
- Shetland: Fair Isle (HZ 221723)
- Orkney: North Ronaldsay (HY 748524)
- Outer Hebrides: Barra (NL 665981)
- Aberdeenshire: Girdle Ness (NJ 972053)
- Fife: Fife Ness (NO 631099)
- Borders: St Abb’s Head (NT 913673)
- Gwynedd: Bardsey Island (SH 118217)
- Glamorgan: Kenfig Pool NNR (SS 802812)
- Pembrokeshire: Porthclais (SM 749242)
- Co Wexford: Hook Head (X 730977)
- Co Cork: Garinish Point (V 505419)
- Co Cork: Cape Clear (V 969226)