Iberian Rarity Bonanza - Late March 2002

It is often said that the British are fascinated by the weather, and why not when we are geographically so well placed to encounter the mercurial moods of our daily weather systems? Different sections of society are more interested in the daily (or hourly) weather forecasts than most, and as birders the highs or lows of our obsession are more often than not dictated by the vagaries of the weather across Britain and Ireland and beyond. The time of the year can influence the importance attached to the weather, and at this time of year birders are particularly interested in weather systems over Western Europe, always on the look out for settled weather conditions to facilitate the arrival of our summer migrants and as conduits for overshooting vagrants. Falls of migrants are exciting stuff, but multiple arrivals of rare and scarce birds are even more exciting for many. Such falls are usually confined to May or the autumn months when wave after wave of migrants carry rarities in their midst. Early spring falls in March are rare, but not unprecedented and these falls often tend to contain small numbers of migrants but a higher proportion of rarities.

2002 has been quite an amazing year so far. We have had several exceptional rarities, extremely mild conditions and a whole rush of very early migrants covering most of our expected 'early' summer visitors by the third week in March. However, rarity enthusiasts watched with great excitement towards the end of last week as the first signs of a large high pressure system stretching from North Africa northwards to the Channel hinted at a weekend of early rarities. As it transpired, the events of the last week have left even the most seasoned and wily of birders somewhat bemused at the hold the weather has over our obsessive pastime as large numbers of Iberian overshoots graced our shores.

Weather Conditions

If we follow the weather charts from last week (click each date to bring up the relevant weather map) an area of high pressure becomes established over the western Mediterranean on the 18th. By the 19th this extends over much of Spain, facilitating the movement of migrants northwards across the western Mediterranean. By Friday 21st this has penetrated northwards to northern France, presenting migrants a corridor of high pressure all the way from North Africa through to the English Channel and creating perfect conditions for overshooting rarities from North Africa and Iberia. Southwesterly and southerly winds dominate over the weekend (23rd and 24th) with winds coming from Iberia northwards and clipping southwest England and hitting southern Ireland. On the 24th the weather systems alter and this window of opportunity for migrant hunters closes, but by now the birds are already in southwest Britain and southern Ireland and it is a case of finding them. By the early part of this week, a large ridge of high pressure moves in to cover much of Britain and Ireland facilitating the reorientation of some birds; other rarities remain, but the numbers of new finds dries up.

The weather conditions appeared to deposit many of the rarities in the southwest of England, but the weather system responsible for producing these birds was only clipping this area and it is likely that the majority of migrants headed further west to make landfall in southern Ireland. The Little Bustard, Black-eared Wheatear and Scops Owl all ensured a steady stream of birders travelling to the southwest, thus it is likely that the large numbers of observers were responsible for turning up good numbers of rarities. By contrast southern Ireland would have relatively few observers at this time of year so in all probability the majority of rarities eluded detection across such a large stretch of underwatched coastline.

The Birds

Many of the birds that arrived were typical of the species that normally return relatively early to the Western Mediterranean. Surprising omissions from the cohort of species recorded were Great Spotted Cuckoo and Red-rumped Swallow - though birders were more than compensated by the species that did turn up!

Night Heron: an adult was present at Tregeseal, St Just (Cornwall) from 26th-27th.

Little Bittern: a male was near Exeter (Devon) on the 27th. As is often the case with early records of this species this bird was picked up moribund early on the 28th.

Little Bustard: one on St. Agnes (Scilly) on 22nd was first seen at Wingletang Down then Troy Town Farm, and was thought to have flown to the inaccessible island of Annet.

Scops Owl: one was present in the car park at Porthgwarra (Cornwall) from 25th-26th.

Pallid Swift: one was positively identified on Bryher (Scilly) from 25th-26th.

Alpine Swift: exact numbers of this highly mobile species are difficult to assess at this early stage with birds seen at sites close to each other several days apart. Perhaps a minimum of 19 birds were involved in the influx from the first seen coming in-off at Ventnor Downs (Isle of Wight) on 22nd. On the 23rd, birds were seen over Tresco (Scilly), St. Ives (Cornwall), two at Baggy Point (Devon) and St. David's (Pembrokeshire). On 24th singles were seen on Skokholm (Pembrokeshire) (perhaps the St. David's bird?), with others seen over Hull (East Yorkshire), Farndon (Cheshire) and Tacumshin (Wexford) and a flock of 5 were seen over Cork City (Cork), and then watched to go to roost. On the 25th just one new bird was noted with one at Aberaeron (Gwynedd). On 26th a maximum of 3 birds were noted over St. Just (Cornwall), with two of these birds noted over Nanquidno, though it is conceivable that these were the birds from North Devon. Several birds lingered for a few days over some sites, but were typically elusive and mobile.

Hoopoe: One on the 17th at Kuggar (Cornwall) was the forerunner of at least another 15 birds. Four birds arrived on the 23rd with singles on St. Martin 's (Scilly), Porthgwarra (Cornwall), Carnsore Point (Wexford) and Minane Bridge (Cork). On the 24th a second bird was found at Porthgwarra. On the 25th, four more birds were found, with singles at Aberdaron (Gwynedd), and Hook Head (Wexford) with two in Cornwall at St. Buryan and Church Cove. The 26th revealed three birds in Cornwall with singles at Grumbla, Catchall and Lamorna Cove, whilst one was on Gugh (Scilly). On the 27th one was on Guernsey. The majority of birds were centred on Cornwall, whilst the Scilly birds could have been the same but are treated as separate here. Several birds lingered, and the two at Porthgwarra proved a popular distraction for birders watching the Scops Owl.

Black-eared Wheatear: male at Nanquidno from 23rd-at least 28th was initially considered to be an eastern bird, then considered a western bird. There is the possibility that this individual exhibits plumage features intermediate between the eastern and western forms, though the jury is still out regarding the true racial identity.

Subalpine Warbler: one was reported on the cliffs between Porthgwarra and St. Levan (Cornwall) on 26th.

Woodchat Shrike: male at St. Levan (Cornwall) from 23rd-27th 500 yards west of the church.

Additional sightings of interest include a Purple Heron over Christchuch (Dorset) might also have been part of the same movement. Several White Storks have also been reported, but this also coincides with the annual walkabout of some of our feral birds and this is presumably the origin of most if not all of these sightings. More interestingly, two Common Swifts were reported, with singles at Woolacombe (Devon) on 23rd and Godrevy (Cornwall) on 24th plus a Swift sp. with five Alpine Swifts over Cork City on 24th. Statistically it is more likely that these birds could well have been Pallid Swifts given the early date and associated species. Surprisingly there were no Great Spotted Cuckoos or Red-rumped Swallows, species normally associated with early weather systems of this nature, but who knows what has been lurking undetected during the period...