02/07/2009
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Foula 2009 Part 2: Drifting away

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Introduction

This is the second instalment of my latest Shetland trip report, documenting rarity-hunting exploits on the remote island of Foula in May 2009. The first ten days of 'Foula 2009' were dominated by westerly winds and a succession of Atlantic low-pressure systems, but my hunch about the island delivering yank rares in such conditions came good in spectacular style with Solitary Sandpiper, Laughing Gull and Pectoral Sandpiper all arriving in a three-day period (see Part 1). However, as the weather began to change and southeasterlies were forecast, would Foula continue to deliver?

Puffin
Puffin, Shetland, May 2009 (Russell Wynn)

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Day 11 (11th May 2009): Foula

Weather: NNW3 to Var1; sunny with light winds.

A large high-pressure system has moved across the UK, and today marks the transition between the westerly-dominated unsettled weather of recent days, and the forecast southeasterlies. The calm, sunny conditions allow me to cover the entire eastern half of the island, but generally it all feels a bit static. There are a handful of new common migrants, including a ringed Dunnock (probably popped up from Fair Isle or North Ronaldsay), at least 30 Swallows, and a Grey Heron flushed from South Ness that departs high north.

Grey Heron
Grey Heron being mobbed by Arctic Terns (Russell Wynn)

Sea-watching off the north end over lunch produces three Common Scoters moving northeast and at least ten Swallows heading north, while a further watch off the south end in calm seas in the late afternoon delivers at least six Harbour Porpoises (with another two off Ham in the evening) and over 120 Arctic Terns lingering offshore.

Pressure chart: 0000 hrs, 11th May 2009
Pressure chart: 0000 hrs, 11th May 2009. The high pressure is edging northwards, and an easterly breeze is already covering southern England. Good times surely lie ahead?

Day 12 (12th May 2009): Foula

Weather: SE-SSE1–2; sunny with light breeze.

Another lovely day, and the inviting southeast breeze immediately produces two very good birds. At 06:30 I'm loafing around in Ham Voe when I hear a sharp 'dzik' and pick up a small, dumpy bird whirring past, coming from the direction of the harbour. I quickly realise it's a Dipper, and head upstream to try and relocate it. I soon find it easily enough, but the bird is surprisingly skittish and easily flushed. However, I manage to get some record shots and reasonable views. I'm fully expecting it to be a Black-bellied Dipper, so am surprised when I see some chestnut tones around the interface between the dark belly and white breast. Current knowledge seems to suggest that birds in northwest Europe without wholly blackish underparts cannot be safely assigned to race, so this bird could have come from anywhere between northwest Scotland (race hibernicus) and central Europe (race aquaticus). Nevertheless, this is still a locally significant record, as the vast majority of previous Shetland records are believed to relate to Black-bellied Dippers.

Dipper
Dipper, much rarer than Pechora Pipit on Foula! Note the obvious chestnut tones at the breast/belly interface (Russell Wynn)

After a spot of lunch I head north, and am walking along the road near Burns when a pale bulky passerine flies up from a grassy verge. As soon as I get bins on it I'm practically blinded by the white rump flashing in the sunshine; it's got to be a Horny Arctic Roll! In flight it appears very cold and frosty-toned, and really quite big, reinforcing my suspicion that it's a Hornemann's Arctic Redpoll, a bird I've previously found on Foula in the autumn. It lands on a peat cutting adjacent to a burn in the nearby valley, and after a careful approach I manage to get brief scope views before it hops out of sight. Knowing that Hornemann's is still a BB rarity, and that photos will be crucial, I stalk the bird to within 15 m and get a series of record shots. It then flies back to the fence-line adjacent to the road but, despite searching, I can't find it again. I return later in the day and spend a further two hours working the fence-lines and peat cuttings, but in the heat and bright afternoon sun I just can't imagine an Arctic Redpoll hanging around, and sure enough the bird is nowhere to be seen.

Hornemann's Arctic Redpoll
Hornemann's Arctic Redpoll; a monochrome delight! (Russell Wynn)

Aside from these two 'bonus' birds, new migrants are again at a premium, with Tree Pipit and Whitethroat being the best of the bunch. However, it just goes to show the unpredictability of island birding, and it's clear that a few oddities are taking advantage of the settled weather conditions to get moving.

Pressure chart: 0000 hrs, 12th May 2009
Pressure chart: 0000 hrs, 12th May 2009. High pressure is now centred directly over Shetland; not the most obvious conditions to expect Dipper and Hornemann's Arctic Redpoll!

Day 13 (13th May 2009): Foula

Weather: ESE2; sunny with light breeze.

Numbers of common migrants remain low, despite the light easterly breeze. However, the quality remains high! At lunchtime I'm returning to Ham after completing a circuit around the south of the island, when I notice a cloud of Bonxies high over Hamnafield Hill. A quick scan with bins picks up a giant shape in their midst: an immature White-tailed Eagle! The eagle gradually drifts south and then turns and heads strongly northeast out to sea, towards Shetland mainland. This wing-tagged bird had been seen over Fitful Head (clearly visible on the eastern horizon) two days earlier, and was apparently released in east Scotland in summer 2007 as part of a reintroduction scheme. Its appearance on Foula is particularly poignant, as I think the island was one of the last breeding locations before the species became extinct at the start of the last century. These days, numbers of breeding Fulmars and Great Skuas are much higher, and I wonder if incoming eagles from recent reintroduction schemes will be able to cope with the inevitable harassment if they attempt to settle.

White-tailed Eagle
White-tailed Eagle on Foula, surrounded by angry Bonxies! (Russell Wynn)

Other new arrivals during the day include single Garden Warbler and Spotted Flycatcher, and three late Pink-footed Geese. A fly-over Common Redpoll is not seen well enough to confirm the racial identification, while other significant sightings include a pair of Redwings seen feeding young, and a colour-ringed Starling that appears to have originated from a population study on nearby Fair Isle.

Ringed Plover
Ringed Plover enjoying the sunshine (Russell Wynn)

Pressure chart: 0000 hrs, 13th May 2009
Pressure chart: 0000 hrs, 13th May 2009. The high pressure is very slowly drifting northeast, but the strongest southeast winds are still located well south of Shetland.

Day 14 (14th May 2009): Foula

Weather: SE2–1; light cloud then sunny with light breeze.

Bird of the day is an elusive Wryneck at Ham, found by Geoff Atherton in the morning. It disappears for a while during the day, but I eventually catch up with it in the evening and manage to get a few record shots of it feeding on a grassy bank.

Wryneck
Wryneck on Foula; the first real 'drifter' of the trip (Russell Wynn)

It appears that the southeast breeze is finally starting to drift a few migrants across, as other new arrivals include Kestrel, Whinchat, Redstart and Pied Flycatcher, amongst small numbers of commoner species. In addition, the redpoll is finally seen well enough at Ham to confirm identification as a 'NW' Common Redpoll.

'NW' Common Redpoll
'NW' Common Redpoll on Foula; note the bold wavy flank streaks (Russell Wynn)

Pressure chart: 0000 hrs, 14th May 2009
Pressure chart: 0000 hrs, 14th May 2009. Conditions are now ideal for drift migrants, although the isobars are not extending very far way east. Therefore, only species originating from the near Continent are to be expected, such as today's Wryneck.

Day 15 (15th May 2009): Foula

Weather: ESE5-E2; sunny with moderate easterly breeze.

For those with sufficient stamina to have read this far, the first two weeks may have come across as a bit of a jolly with rare birds just dropping out of the sky. However, I can assure you that after fourteen days of trekking up and down hills, wading through bogs, clambering over walls, stiles, boulders, sheep, etc., while carrying my own body weight in optics, I'm starting to feel a bit frayed around the edges! Despite having lots of gale-force winds in the first week, it's actually been a very dry fortnight; consequently there has been barely any weather downtime. In addition, the birding has been relentlessly interesting, and even on quiet days there has always been the gnawing paranoia that something might be lurking in the next ditch, or hiding behind the next dry-stone wall. Another aspect of Shetland birding is the phenomenon of afternoon falls. At home on the south coast I'm used to early starts and satisfying post-lunch naps. On Shetland you can thrash the key sites in the morning for little reward, when suddenly birds start popping up all around you and you're obliged to do the rounds again. It's all great stuff, but not recommended if you don't like wind, hills, blisters, or looking in the mirror and not recognising what you see.

Foula
The bulky outline of Foula is just visible on the western horizon, viewed from Shetland mainland. Note the 'undulating' backbone of the island (Russell Wynn)

Anyway, today I get some much-needed back-up when Ken Shaw flies in, and he picks a good day to arrive as the southeast winds start delivering a decent variety of drift migrants. The day starts well with a fine male Blue-headed Wagtail at Ham and a Sand Martin zips through. In the afternoon a male Crossbill arrives on the bird table outside the Atherton residence, and wastes no time in terrorising the resident sparrows!

Common Crossbill
Male Crossbill feeding on peanuts (Russell Wynn)

Also found during the afternoon are a cracking male Bluethroat at Burns and a Short-eared Owl at Harrier, while the Wryneck remains at Ham. Totals of other notable migrants include a Merlin, two Whinchats, five Tree Pipits, five Redstarts and five Pied Flycatchers (one male and four females).

Bluethroat
Record shot of the male Bluethroat (Russell Wynn)

However, the best birds arrive in the evening, with a pair of Garganey flushed from the Ham Burn, an overflying Wood Sandpiper, and a Honey Buzzard drifting north at dusk. Things are really moving through quickly! The latter bird is particularly notable as it brings my Foula trip list to 100 species; interestingly this total has been achieved faster than during any of my previous autumn trips.

Pressure chart: 0000 hrs, 15th May 2009
Pressure chart: 0000 hrs, 15th May 2009. The southeast breeze over Shetland starts to increase, and the drift migrants arrive in force.

Day 16 (16th May 2009): Foula

Weather: ESE5–7; sunny then light cloud with stiff easterly breeze.

Unsurprisingly, we can't match the intensity of the previous day, even though the east wind strengthens to near gale force. A male Cuckoo and a Common Sandpiper at Hametoun are new arrivals, and numbers of Pied Flycatchers increase to nine (including three males).

Pied Flycatcher

Pied Flycatcher

Pied Flycatcher

Pied Flycatcher
Pied Flycatchers on Foula; note the variability in size and shape of the white patch at the base of the primaries. Also note the large parasite (probably a tick) just behind the eye of the second bird (Russell Wynn)

In addition, the Blue-headed Wagtail and Crossbill remain at Ham, and there are now two 'NW' Common Redpolls there. Despite a good scatter of other common migrants, the lack of any really rare drift migrants is a bit disappointing, especially after five days of southeast winds. Is the weather system too localised, or are the bright conditions enabling birds to reorient efficiently?

Pressure chart: 0000 hrs, 16th May 2009
Pressure chart: 0000 hrs, 16th May 2009. Low pressure dominates over the UK, wrapping strong easterlies around its northern edge and across Shetland. Note the fronts stretched across the North Sea that are drifting slowly northwards.

Day 17 (17th May 2009): Foula

Weather: SE6–5; light rain then cloudy before more rain in evening.

After a week of constant sunshine the weather finally turns unsettled, with rain at both ends of the day. A good scatter of quality migrants are again recorded, with the highlight being a male Bluethroat and a male Ring Ouzel at Harrier, and a male Grey-headed Wagtail that I glimpse briefly at Ham. Other significant new arrivals included a single Swift and a late influx of thrushes, with single Song Thrush and two each of Redwing and Fieldfare. An adult 'Scandinavian' Lesser Black-backed Gull at Mill Loch is a good Shetland record. However, best finds of the day go to the Athertons, with a male Subalpine Warbler found by Geoff and an Icterine Warbler found by Donna, both seen briefly in the Ham area but not relocated. A male and a female Blue-headed Wagtail are also lingering at Ham, with the male Crossbill and a male Cuckoo (constantly mobbed by the breeding Redwings) also there.

Redwing and Cuckoo
A rare sight in the UK: a Cuckoo being mobbed by a breeding Redwing! (Russell Wynn)

A good mix of commoner migrants are also scattered around the island. To give an idea of the variety and numbers, the daily log (in addition to the birds listed above) is as follows: single Whooper Swan, Grey Heron, Grey Wagtail, Sedge Warbler and Lesser Whitethroat, two Greylag Geese, two Dunlin, two House Martins, two Spotted Flycatchers, three Pink-footed Geese, three Whinchats, four Whitethroats, four Garden Warblers, five Chiffchaffs, six Tree Pipits, six Redstarts, 11 Willow Warblers, 11 Pied Flycatchers (six males), 25 Swallows and about 35 Oystercatchers (flying overhead in two flocks).

Pied Flycatcher
Male Pied Flycatcher on Foula (Russell Wynn)

Pressure chart: 0000 hrs, 17th May 2009
Pressure chart: 0000 hrs, 17th May 2009. A series of fronts introduce rain into Shetland. These conditions, together with the easterly breeze, induce the arrival of Subalpine Warbler, Icterine Warbler, Bluethroat, Grey-headed Wagtail and a fresh wave of common drift migrants onto Foula.

Day 18 (18th May 2009): Foula

Weather: SE6–5; light rain then cloudy before more rain in evening.

Today is my final day on Foula, so I get up extra early and have a quick look around Ham on my own before breakfast. Almost immediately, I relocate and photograph the male Subalpine Warbler, and also manage to get brief but satisfying views of the cracking male Grey-headed Wagtail that I glimpsed the previous day.

Subalpine Warbler
Male Subalpine Warbler on Foula (Russell Wynn)

The male Crossbill and male and female Blue-headed Wagtails also remain, and two Cuckoos are now present, doubly annoying for the breeding Redwings! A nice first-summer male Ring Ouzel is new in, as are about 15 first-summer Common Gulls. At breakfast I hear that my outward flight is delayed due to strong crosswinds, but while waiting around I see Ken grilling something in the Post Office garden, which turns out to be the Icterine Warbler from the previous day. A technical fault with the plane, then poor visibility due to low cloud, delay my flight still further, but I finally depart late afternoon and spend the night at Sumburgh.

Ken Shaw
Ken Shaw grilling the Icterine Warbler at Ham (Russell Wynn)

Pressure chart: 0000 hrs, 18th May 2009
Pressure chart: 0000 hrs, 18th May 2009. The pressure chart looks almost identical to the previous day, with the easterly breeze and associated fronts remaining over Shetland.

Day 19 (19th May 2009): Shetland South Mainland

Weather: SSE4; light cloud then sunny spells.

A dash up to Sumburgh Head before my flight south produces a scatter of common migrants including Robin, Whinchat, Redstart, Tree Pipit, Lesser Whitethroat and Spotted Flycatcher.

Spotted Flycatcher
Spotted Flycatcher at Sumburgh Head (Russell Wynn)

The cliffs hold large numbers of breeding seabirds, and my final few minutes in the field are spent soaking in the sights and sounds of countless auks, Fulmars and Kittiwakes. What a great way to finish the trip!

Auk colony
Auk colony at Sumburgh Head (Russell Wynn)

Summary

So after 19 days in the field, how did it all pan out? Well, my final trip total for Foula came to 107 species, with three self-found BB rarities (Solitary Sandpiper, Laughing Gull and Hornemann's Arctic Redpoll) and a good supporting cast of scarce finds, including Garganey, White-tailed Eagle, Honey Buzzard, Pectoral Sandpiper, Wood Sandpiper, Pomarine Skua, Dipper, Grey-headed and Blue-headed Wagtail, Bluethroat and Lapland Bunting (as well as a couple of Iceland Gulls on Shetland Mainland). With the addition of Great White Egret, Wryneck and Subalpine and Icterine Warbler found by others, it could certainly be classed as a successful trip. The fact that I managed to photograph all of the key birds, and didn't have any 'near-misses', was also reassuring. As a single observer on a remote island, there is always a nagging doubt at the back of your mind that 1) you might find something crippling but fail to nail it, 2) people won't believe you if you do find a series of good birds, or 3) that you've made a mistake with a crucial identification, especially after posting images on the web!

Finally, let's return to the key question that inspired this latest expedition. Can Foula deliver in spring? Well, the first week speaks for itself. When fast, eastwards-moving, low-pressure systems track across the northern UK in early May, Foula is probably as good as anywhere to deliver yank rares. The downside is that there may not be much of a supporting cast in such conditions, and life in the field can be a little 'uncomfortable'. That said, it is normally possible to find a bit of shelter along the coast, and sea-watching can produce small numbers of Pomarine Skuas to keep things ticking over.

However, in classic 'drift' conditions, with southeast winds and high pressure to the north and east, it appears that Foula is definitely outshone by Fair Isle, North Ronaldsay, and other sites further east on Shetland Mainland. To put some figures on this last statement, peak counts for some of the scarcer drift migrants for the period 15th–18th May are as follows:

SpeciesFoulaFair IsleNorth RonaldsayOther Shetland
Tree Pipit6?1512
Grey-headed Wagtail1044
Bluethroat2151017
Subalpine Warbler1010
Icterine Warbler1322
Wood Warbler0?610
Pied Flycatcher1125821
Red-backed Shrike0003

The discrepancy in Bluethroat numbers is especially striking, and somewhat galling as they're one of my favourite birds! In addition, numbers of commoner migrants such as Whinchat, Redstart, Willow Warbler and Spotted Flycatcher were usually much higher on Fair Isle and North Ronaldsay compared to Foula, often at a ratio approaching 10:1.

Although it was great to be in on this arrival of colourful drifters, it is particularly notable that during the whole period from 12th–19th May, when a stable weather system produced a consistent southeasterly airflow across Shetland, not a single 'eastern' BB rarity was found on the archipelago. The best birds were a Rustic Bunting on Whalsay and Subalpine Warblers (presumed to be of the eastern race) on Foula and North Ronaldsay. OK, so they're 'ex-BB rarities', but it still seems likely that the lack of penetration of the southeasterly airflow into central and eastern Europe ensured that only drifters from the near-Continent arrived. It does make you wonder whether southeast winds are all they're cracked up to be when it comes to finding really rare birds on Shetland.

Next year I hope to be able to return to Foula in May to follow-up on some of the findings from this spring, and maybe put a bit more time into sea-watching in search of that elusive White-billed Diver. But what about all those southern overshoots that I've yet to find? Maybe I should consider St Agnes instead? And I've yet to experience the Outer Hebrides skua passage in spring. Won't Fair Isle have a shiny new observatory? Now where did I put that map...?

Pot-bellied Pig
The Beast of Foula, usually found lurking around the ditches in Hametoun. I've been told it's a Pot-bellied Pig and it's harmless, something I could have done with knowing when it first came at me! (Russell Wynn)

Many thanks to the Foula residents for providing access across their land, and especially to those who provided accommodation during my stay. I’m also grateful to Geoff Atherton, Donna Atherton and Ken Shaw for helping me stay mentally upbeat towards the end of the trip, especially when my feet just wanted to stop running!
Written by: Russell B Wynn