Report on scarce migrant birds in Britain in 2018

Steve White and Chris Kehoe

Introduction

This report presents data on scarce passerine migrants recorded in Britain during 2018. For comments on how the data are presented, see the introduction to part 1 (p. 462). For the majority of species in this report, their number, distribution and occurrence pattern fell within the expected norms. But for a small number, 2018 stands out. For Rose-coloured Starling Pastor roseus this was an exceptional year, as an invasion of eye-catching spring adults from the east spread across continental Europe. By mid June birds had reached all parts of Britain, including many inland sites, and by the year’s end the final tally was 162, the second-highest annual total. Dusky Warbler Phylloscopus fuscatus enjoyed its fifth-best year (25 records), but in contrast it was a blank year for its Siberian congener, Radde’s Warbler P. schwarzi, the first since 1983. For aficionados of the genus Acrocephalus, 2018 was a year to savour with 19 Blyth’s Reed A. dumetorum and 86 Marsh Warblers A. palustris, the third-best showing for both species. Although numbers of Bluethroats Luscinia svecica are declining – the current decade average is less than 40% that of the 1980s – 2018 was an unexpectedly good year for ‘White-spotted Bluethroats’ L. s. cyanecula with 16 reported compared with the 2008–18 average of less than two. 

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312. Greenish Warbler Phylloscopus trochiloides, St Agnes, Isles of Scilly, October 2018. 

Jim Almond

For three species recently arrived in this report from the BBRC list, the year was disappointing. There were just six Penduline Tits Remiz pendulinus, four Red-flanked Bluetails Tarsiger cyanurus and eight Citrine Wagtails Motacilla citreola. The ten-year mean for each species now lies at or close to the trigger for re-entry to the BBRC sphere. Hopefully the next report will see their fortunes revive. With just 12 records, Short-toed Lark Calandrella brachydactyla had another poor year; since 1982 there have been only two years with fewer records. Melodious Warbler Hippolais polyglotta also gives cause for concern as the annual total continues to decline; with just 17 this year, the downward trend shows no sign of levelling out. This is one species that should benefit from climate change, but the English Channel appears to be an insurmountable hurdle.

Looking to the future, two species groups make their final appearances in this report. The ‘Subalpine Warbler’ complex and the Arctic Redpolls Acanthis h. hornemanni and A. h. exilipes return to the BBRC fold from 1st January 2019. The decision announced by IOC to treat Subalpine Warbler Sylvia cantillans as two species (Western Subalpine and Eastern Subalpine Warbler) will add to the identification headaches caused by the difficulties of separating these two taxa, from each other and from Moltoni’s Warbler S. subalpina. BBRC has already set out tough acceptance criteria (Brit. Birds 113: 364) and it seems that inevitably many records will fall into the either/or category.

Red-backed Shrike Lanius collurio

After one at Seaford (Sussex) on the fairly typical first date of 6th May, a further 76 appeared in May and 29 in June. The spring passage is always heavily concentrated in May and the first ten days or so of June – there have been only four in April since 2008 (fig. 1). This year, 38 were reported as males and 44 as females.

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Fig. 1. Arrival dates of Red-backed Shrikes Lanius collurio in Britain, 2008–2018.

Autumn passage is always more protracted. There were single females at Sandwick on 1st July and on Foula on 4th (both Shetland, and both arguably better treated as late spring migrants) with one other that month followed by 13 in August, 19 in September and four in October. There were two late records, at Crossness (Greater London) on 4th–13th November and Newbiggin (Northumberland) on 2nd–4th December – the first in Britain in December since at least 2001. Twenty-six autumn birds were reported as juveniles and none as adults after July; the earliest juvenile was on the Farne Islands (Northumberland) on 13th August.

Throughout the year Red-backed Shrikes were recorded in 27 recording areas, including six in Scotland and three in Wales. Shetland was the top county with 30, followed by 19 on Fair Isle, 15 in Yorkshire, 14 in Northumberland, 13 in Norfolk and ten in Orkney.

(Widespread breeder from N Spain E to Greece & N through Europe to C Fennoscandia, Russia E to Ob River in C Siberia, Turkey & Caucasus region S to NW Iran. Winters equatorial & S Africa.)

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313. First-winter Red-backed Shrike Lanius collurio, Wanstead, Greater London, September 2018. 

Brian Anderson

Great Grey Shrike Lanius excubitor

Numbers were down compared with last year on all measures (2017 figures in parentheses): 138 (194) birds were reported, of which 103 (137) were thought to be new arrivals, but the upward trend over the past couple of decades remains significant.

At least 18 had overwintered from 2017, including three in the Clocaenog Forest (Denbighshire) but it is likely that most of the 15 first reported during January and February, and perhaps some of the four in March, had also done so. April produced eight records, the last at Musden Head Moor (Lancashire & N Merseyside) on 22nd, and these presumably included some immigrants. No more were seen until one at Blakeney Point (Norfolk) on 7th October, which was followed by a further 45 new birds that month, then 15 in both November and December.

Shetland, with 17 presumed new birds, was by far the best county, the only other significant county tallies being nine in both Norfolk and Yorkshire, a distribution which is not atypical. The Great Grey Shrike is the most widely distributed of Britain’s scarce migrants, having been recorded in all but four recording areas since 2008.

(Nominate race breeds Fennoscandia, C Europe & Russia E to NW Siberia. Other races breed Canary Islands, N Africa, SW Europe & Middle East to S Kazakhstan, Mongolia, N China, S to Pakistan & India. Northern breeders migratory, wintering to S of breeding range.)

Woodchat Shrike Lanius senator

Although 17 is the lowest annual total since 2007, the impact on the table of annual means is limited. Woodchat Shrikes were recorded in 13 counties in 2018, including three in Scotland and two in Wales; Scilly was the top county, with three. 

Three birds appeared in April, the first on St Agnes (Scilly) on 9th–20th, and the spring passage was completed with four in May and three in early June, the last at Scaling Dam (Cleveland) on 12th–14th. After a midsummer record of one at Long Dale (Derbyshire) on 4th July, two juveniles appeared in the second half of August. No more were seen until another three in late September, followed by the last, a bird at Sumburgh and then Virkie (Shetland) on 11th and 16th October. Four autumn birds were reported as juveniles and just one as an adult. This relatively even split between spring and autumn was rather unusual as spring records on average outnumber those in autumn by more than three to one (fig. 2).

(Breeds NW Africa & Mediterranean Europe N to C France & S Germany, E through S Turkey to W Iran & S to Israel. Winters in N & C equatorial Africa.)

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Fig. 2. Arrival dates of Woodchat Shrikes Lanius senator in Britain, 2008–2018.

Golden Oriole Oriolus oriolus

Although these numbers represent a slight improvement over 2017, the overall decline continues. The first, at Walton Bay (Avon) on 19th April, was followed by another ten records that month, 26 in May and 11 in June, mostly in the first fortnight but with a late spring migrant at Speech House Lake (Gloucestershire) on 26th–29th. In autumn there were two in the third week of July, in Yorkshire and Scilly, and three in September, the last on Foula (Shetland) on 25th–26th. 

Nine of the 53 birds were in Scotland – in Shetland and Orkney and one in Clyde – but none occurred in Wales, the first blank year there since 2004. Since 2008 most records have been in southwest England, with a remarkable 30% of them on Scilly alone.

(Breeds NW Africa & widely throughout Europe from Mediterranean N to S Sweden & S Finland, Russia, Turkey & Caucasus to NW Iran. Winters equatorial & southern Africa.)

Penduline Tit Remiz pendulinus

Although the 2018 total is a marginal improvement on the four records last year, there was no sign of any genuine resurgence; indeed, the total of six new birds may actually have included one from 2017 (see below). The ten-year mean now stands at 10 and, although double-figure numbers have been recorded in four years in that period, the status of Penduline Tit as a scarce migrant rather than a national rarity hangs in the balance. All records are shown below.

Dorset Radipole Lake, 1CY+, 14th–27th December

Gloucestershire Longford, 1CY+ male, 16th December 2017 into 2018 (plate 314)

Greater London Crossness, 1CY+, 10th November into 2019

Hertfordshire Tyttenhanger Gravel-pits, 2CY+, 16th–17th April (possibly the same as Gloucestershire above, on the basis of a partially read ring number; the bird was ringed on Alderney in autumn 2017)

Suffolk Leathes Ham, Lowestoft, 2CY+ male, 2nd–3rd April; Southwold, 1CY+, 2nd November 

Surrey 24th–25th March, 2CY+ male, Walton Reservoir

(Widely but locally distributed throughout C & E Europe, from Denmark, Germany & Italy NE to C Sweden & Estonia. Absent from much of NW Europe but locally numerous Spain. To E, breeds Turkey, Caucasus region, N Iran, S Russia and W & N Kazakhstan. Largely resident or dispersive in Europe.) 

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314. Male Penduline Tit Remiz pendulinus, Longford, Gloucestershire, February 2018. 

Brian Anderson

Short-toed Lark Calandrella brachydactyla

Since 1982, only two years, 2005 and 2015, have produced fewer than 12 records and a steady decline appears to be under way, although not yet significant statistically (fig. 3).

One at Blakeney Point (Norfolk) on 6th–7th May was the first of the year. It was followed by another six in May, then one in September and four in October, the latest at Rosketal (Cornwall) on 22nd–31st.

Occurrences were restricted to eight recording areas: Norfolk had three records, Scilly, Cornwall and Shetland each had two, and Devon, Somerset and the Isle of May one apiece. 

(Breeds NW Africa & European Mediterranean basin to Black Sea region of Turkey & S Russia, E through C Asia to Mongolia & NW China. Winters along S edge of Sahara from Senegal to Sudan, Arabian Peninsula & N Indian subcontinent.)

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Fig. 3. Annual totals of Short-toed Larks Calandrella brachydactyla in Britain, 1990–2018.

Red-rumped Swallow Cecropis daurica

An average year began with two at Lizard Point (Cornwall) on 14th April; 13 more arrived later in the month including two at Gibraltar Point (Lincolnshire) on 23rd. May provided a further 16 records, including the only other multiple record of the year when two were at Kingsdown (Kent) on 24th. The spring passage of 33 birds concluded with two in the first week of June, the last one being at Posting (Kent) on 7th.

The autumn movement is almost always far less significant than that in spring (fig. 4) and this year was no different. The first, at Church Stretton (Shropshire) on 1st September, was followed by two in October and then a remarkable three records in December: at Cley (Norfolk) on 5th–9th with perhaps the same bird at Kessingland (Suffolk) on 10th, and another at Torpoint (Cornwall) on 9th–13th. There has been only one previous December sighting of a Red-rumped Swallow since 2008: a juvenile at various coastal sites in north Norfolk from 17th December 2015 to 1st January 2016.

Red-rumped Swallows were recorded in 17 areas, three in Scotland (Fair Isle, Shetland and at sea off Caithness) but none in Wales; Kent with ten records and Suffolk with five were the top English counties.

(Race rufula widespread breeder from NW Africa & Mediterranean Europe N to S France & E through Balkans & Greece to W & S Turkey, Middle East & C Asia. Other races breed Africa and S & E Asia. Winters to S of breeding range in N equatorial Africa, Indian subcontinent andSE Asia to N Australia.)

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Fig. 4. Arrival dates of Red-rumped Swallows Cecropis daurica in Britain, 2008–2018.

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315. Red-rumped Swallow Cecropis daurica, with Barn Swallows Hirundo rustica, Fair Isle, May 2018. 

Richard Cope

Pallas’s Leaf Warbler Phylloscopus proregulus

For the first time since 2012 there were no records in the early part of the year; the modest total in 2018 occurred entirely during the traditional peak period of mid October to late November. The first of the year was at Holy Island (Northumberland) on 11th October. A further 18 were found that month and 15 more in November, the last at Wells (Norfolk) from 26th until 1st December (this being the only bird to linger for more than a couple of days; most were recorded on one day only). 

Norfolk, with eight records, was the top county, followed by Kent with five and Suffolk with four. All were singles apart from two at Walton-on-the-Naze (Essex) on 17th–18th November. Scotland had three records this year but none were found in Wales.

During October, all but one bird (in Devon) were on the east coast between Shetland and Kent but nine of the November birds were on the English south coast between Sussex and Cornwall. Whatever the factors were that led to the meteoric increase in records of Yellow-browed Warbler P. inornatus, the same factors clearly do not apply to Pallas’s Leaf Warbler, which shows no overall trend in sightings over the past 30 years.

(Breeds S Siberia from Baikal region E to Ussuriland, NE China & S to N Mongolia. Winters E China to S of Yangtze River & throughout Indochina S to C Thailand.)

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316. Pallas’s Leaf Warbler Phylloscopus proregulus, The Naze, Essex, November 2018. 

Kit Day

Radde’s Warbler Phylloscopus schwarzi