Lesley Ball

Abstract On the afternoon of 14th October 2018, a swift with a white rump was found at Hornsea Mere, Yorkshire. The bird was initially feeding alone but later joined a group of House Martins Delichon urbicum at the western end of the mere, where it showed well and was photographed. After some initial deliberation over its identity, photographs established that this was a White-rumped Swift Apus caffer. Many observers were able to enjoy this first for Britain before it disappeared as the light began to fade, and it was not seen again. The record has been accepted by BBRC and BOURC and added to Category A of the British List.

It was raining heavily on Sunday 14th October 2018 and I was doing chores at home in my bungalow, which overlooks Hornsea Mere, in the East Riding of Yorkshire. At 15.00 hrs, I made myself a coffee and headed to the front-room window, which gives extensive views over the southern end of the nature reserve. This means I’m able to enjoy birding my favourite patch from the comfort of home, which is especially welcome when the weather is unpleasant. Gazing through the rain-spattered windowpane across to the reedbed and the mere, and then to the field slightly to the south, I noticed what appeared to be a swallow-sized bird with fluttery flight and jizz. It was quite distant, some 300 m or more, and flying around two Ash trees Fraxinus excelsior. At this point I could make out only its overall dark plumage and that it had white flashes somewhere in its plumage. Thinking that it was getting quite late for a Barn Swallow Hirundo rustica, I put the record out on our Merebirders WhatsApp group, at 15.15 hrs.

Since the rain had eased, I wandered into the garden and noticed the same bird fly across the field towards the mere. At this point I thought it was worth a second look so I crossed the road, entered the field and walked 100 m towards the mere. When I was about 30 m from the mere, I suddenly saw it again, this time flying just above the reedbed that fringes the edge of the mere. Though the bird was in view for only a few seconds before disappearing behind a Willow Salix caprea, it was coming directly towards me. In this brief view it turned sharply, rose up and almost seemed to come to a halt in mid-air, just 6 m from where I was standing. At this point, I gasped – it had a white rump, instantly making me think of a Red-rumped Swallow Cecropis daurica. But its flight and jizz differed, and the overall blackish plumage with a white rump, and the shallow fork in the tail were clearly wrong for Red-rumped Swallow. This was something quite different. The bird clearly was a swift but not a Common Swift Apus apus. I judged it to be definitely smaller and more delicate than a Common Swift, and its narrow, scythe-shaped wings and slim body gave it an elegant flight and, to me, an almost cute appearance.

Over the next few minutes I watched it as it flew around the tops of the taller Ash trees where, at times, it towered up then descended in the manner of a Swallow. It also flew low over the reedbed and mere. It was difficult to make out plumage details, other than the striking white rump, but during its closer passes I was able to see that the throat and face were slightly paler and greyer than the darker body, and that the dark eye and short black bill contrasted with this paler area. 

The bird then flew out of view across the mere, so I contacted Jon Lamplough (JL) who was birding on the reserve. We discussed possibilities of it being either a House Martin Delichon urbicum or a Barn Swallow, both species he had already seen on the reserve that morning. I countered each of his arguments with features that were at odds with both of his suggestions and stood firm that this was a swift. All this had happened very quickly. I posted another message on the Merebirders group at 15.24 hrs, alerting members that the bird was a swift with a white rump.

I returned home and began searching through my copies of the Collins Bird Guide (Svensson et al. 2009) and A Field Guide to the Rare Birds of Britain and Europe (Lewington et al. 1991). I had just found the pages illustrating White-rumped Swift A. caffer when George Bennett (GB) arrived. As we discussed the various options, JL also arrived and headed into the field where I had last seen the bird. Suddenly a great roar came from GB – the bird had returned. After confirming the features that I had already seen on the bird, they tentatively identified it as a Pacific Swift A. pacificus (itself an extreme rarity with just eight accepted UK records at the time) and put the news out as this species.

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Richard Williston

56. White-rumped Swift Apus caffer, Hornsea Mere, Yorkshire, October 2018. 

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John Hewitt

White-rumped Swift Apus caffer, Hornsea Mere, Yorkshire, October 2018.

 

Birders soon began to descend on the mere and, as the crowd grew, birders with experience of Pacific Swift began to question the identification. Pacific Swift is a large swift, slightly larger than Common Swift, whereas it was generally agreed that the Hornsea bird was smaller and showed a more delicate structure than a Common Swift. Furthermore, some observers noted what appeared to be a narrow white trailing edge to the secondaries – a feature at odds with Pacific Swift but diagnostic for White-rumped Swift. But not everyone could make out this feature, and I hadn’t seen it either, despite my earlier good, close views. Photographic documentation was required to establish exactly what was being seen. 

The bird then moved to fields closer to the western end of the reserve, where it fed over the mere with a small group of House Martins. GB, in his role as the Wassand estate warden, kindly allowed access to these fields, and photographs taken there clearly showed a white trailing edge to the secondaries – the bird was indeed a White-rumped Swift! The revised identification was broadcast, leaving travelling birders with just 90 minutes of daylight in which to reach the mere. The bird remained in view until 18.10 hrs but as the weather began to deteriorate it drifted away in rapidly failing light. It was not seen again that day nor the following day. I understand that around 150 birders saw the swift before it departed. Many more turned up afterwards and some remained on site throughout the following day.

Description

Structure and size

The bird was similar in size to a Barn Swallow, and smaller than a Common Swift. Its structure was that of a swift, with long, narrow, scythe-shaped wings and a slim body, and it appeared smaller and more delicate than a Common Swift, giving it an elegant appearance in flight. The tail was narrow but distinctly forked.

Plumage

The crown and sides of the head were black and contrasted with the paler, greyish throat, forehead feathering just above the bill and loral feathering around the bill base. The entire underparts, including the tail and underside of the wings, were dark, appearing blackish. The upperparts were also dark and appeared blackish in the field apart from a conspicuous white band across the rump and a narrow white trailing edge to the secondaries on both wings, formed by a pale tip to each secondary feather. 

Bare parts

The bill was short, typical of a swift, and dark; the eye was also dark. The legs were not seen.

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Tim Jones

58. White-rumped Swift Apus caffer, Hornsea Mere, Yorkshire, October 2018. 

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Tim Jones

59. White-rumped Swift Apus caffer, Hornsea Mere, Yorkshire, October 2018.

Behaviour

During my initial observations of the swift feeding around the tops of the taller Ash trees, there were times when it towered then descended in the manner of a Swallow, and it appeared to be taking insects flying above the decaying leaves. It later flew towards the mere and began hawking low above the reedbed. Here its flight was slightly undulating; somehow, I thought it seemed languid and steady. As the weather conditions improved, it joined a group of House Martins feeding at the western end of the lake and remained with them until dusk, when it gained height, flew into the distance and was then lost to view. 

Previous records in northern Europe

Despite many birders being taken aback by the arrival of this unexpected swift in Yorkshire, sightings of White-rumped Swift in northern Europe are not unprecedented. Earlier appearances include: 

- Järvikylä, Pohjois-Pohjanmaa, Finland, on 18th November 1968; apparently found exhausted and later died (Lewington et al. 1991)

- Two birds at Eftang, Vestfold county, Norway, on 15th June 1986 (Vår Fuglefauna 13: 136)

- Stenshuvud, Skåne, Sweden, on 27th October 2013 (Fågelåret 2013: 117–118)

In addition, a small swift with a white rump and forked tail was photographed at North Bull, Co. Dublin, on 25th December 2002, and was considered mostly likely this species (Persson 2003). A final decision on the identification of this bird was postponed but the record is now back in circulation (H. Hussey pers. comm.).

A previously accepted record from Jomfruland, Telemark, Norway, on 18th May 1984 is no longer considered to be acceptable (Geir Mobakken in litt.) and following review, a claim from Wein, Austria, on 17th June 2004 remains unproven (Albegger & Laber 2016).

Discussion

The White-rumped Swift is a common and widespread species in sub-Saharan eastern and southern Africa. Farther west it is less numerous and its distribution becomes patchy and more localised. The most westerly regular breeding location is the Parc National du Niokolo-Koba, Senegal. Within Africa birds are believed to be resident or nomadic, although movements are poorly understood. A few pairs breed north of the Sahara in the High Atlas, Morocco, but the size of this population is unknown. 

In Europe, it was first recorded in August 1962 near the Laguna de la Handa in southern Spain; at the time, the bird was considered to be a Little Swift A. affinis, which breeds commonly in nearby Morocco (Gooders 1971). This was followed in 1964 by up to three birds in the Sierra de la Plata, near the town of Tarifa in Cadiz province. Breeding was first recorded in 1966, when four nests were discovered, all in the disused nests of Red-rumped Swallows. It was not until 1968 that it was finally confirmed that these birds were White-rumped Swifts and not Little Swifts (Gooders 1971). Since this time, its range in Spain has spread east into Almeria and north to Cordoba provinces. The current European breeding population is believed to be in the range of 110–200 pairs (BirdLife International 2017) in southern Spain and Portugal. 

Tracking studies have shown that White-rumped Swifts remain in southern Europe until October, generally later than other breeding swifts, and then can take up to six weeks to reach their wintering areas in West Africa (Lomas Vega et al. 2019). Birds may occasionally linger in Spain into the winter but this is unusual.

Autumn 2019 proved to be outstanding for southern swifts reaching northwest Europe and the UK. Coinciding with the White-rumped Swift at Hornsea Mere, a Pallid Swift A. pallidus was found at Church Norton, Sussex, on 13th October (Holt et al. 2019), while in the Netherlands single Pallid Swifts appeared at three locations on 13th, 14th and 15th October (Gelling et al. 2019). In November a more concerted arrival of Pallid Swifts occurred, with at least 14 more arriving in the UK between 10th and 15th November (more submitted records are currently being assessed) and 11 in the Netherlands (Gelling et al. 2019). In addition, a Little Swift was found in Cleveland on 11th–12th November (Holt et al. 2019). It is thought that swifts may be susceptible to displacement by plumes of warm, fast-moving air extending out of North Africa and into northern Europe at this time of year. The timing of northern European records suggests that late autumn may be the best time to encounter one of these delicate swifts in northern Europe. 

Acknowledgments

I would like to give special thanks to George Bennett for arranging access to the Wassand estate, and also to Rupert Russell (estate owner) and Mike Jebson (estate manager) for allowing access to this private land adjacent to Hornsea Mere. My thanks also go to Jon Lamplough for help with the identification of this swift, Jeff Cox for facilitating the speedy release of the news via the Merebirders WhatsApp group, and Mark Robinson for his encouragement and guidance during the writing of this article. Geir Mobakken supplied the details of White-rumped Swift records from Norway, Sweden and Finland, and Harry Hussey provided an update of the bird at North Bull, Dublin, in December 2002.

References

Albegger, E., & Laber, J. 2016. Undocumented first records of bird species in Austria 1950–2011 – results of a review using consistent criteria. Eighth report of the Avifaunistic Commission of BirdLife Austria. Egretta 54: 105–109.

BirdLife International. 2017. European Birds of Conservation Concern: populations, trends and national responsibilities. BirdLife International, Cambridge.

Gelling, G., van der Spek, V., Lidster, J., & CDNA. 2019. Rare birds in the Netherlands in 2018. Dutch Birding 41: 375–400.

Gooders, J. (ed.). 1971. ‘African White-rumped Swift.’ In: Birds of the World. Vol. 5., pp. 1419–1420. IPC Magazines, London.

Holt, C., French, P., & the Rarities Committee. 2019. Report on rare birds in Great Britain in 2018. Brit. Birds 112: 556–626.

Lewington, I., Alström, P., & Colston, P. 1991. A Field Guide to the Rare Birds of Britain and Europe. HarperCollins, London.

Lomas Vega, M. et al. 2019. Migration strategies of Iberian breeding White-rumped Swifts Apus caffer, Rufous-tailed Scrub-Robins Cercotrichas galactotes and Bluethroats Cyanecula svecica. Ardeola 66: 51–64. 

Persson, S. 2003. The White-rumped Swift in Dublin. Birding World 16: 16–17

Svensson, L., Mullarney, K., & Zetterström, D. 2009. Collins Bird Guide. 2nd edn. HarperCollins, London.

Lesley C. Ball, Yorkshire; e-mail [email protected]

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John Hewitt

60. White-rumped Swift Apus caffer, Hornsea Mere, Yorkshire, October 2018.

Paul French, BBRC Chairman, commented: ‘Accepted quickly and unanimously in a single circulation, this was undoubtedly one of the birds of the year for those lucky enough to get to Hornsea Mere in time. And one of the big dips for the unfortunate folk who arrived as the light faded, minutes after it was last seen heading inland. Although the identification was confirmed from photographs, this happened in real time and enabled those within 90 minutes or so of Hornsea to get there and enjoy excellent views of this enigmatic species. 

‘As alluded to above, White-rumped Swift has been on the radar of swift watchers for many years, with the recent Swedish record being the wake-up call many were looking for. The identification of our three “white-rumped” swifts (Pacific, Little and White-rumped) is dealt with in the existing literature, and in her account Lesley Ball has also highlighted the rather distinctive, delicate and swallow-like jizz of White-rumped as a feature, as opposed to the more “super-swift” jizz of Pacific Swift. This is likely to be easier to see on distant birds, when confirming the presence or absence of a white trailing edge to the secondaries may be impossible, and may provide future observers of a “white-rumped” swift with enough clues to put news out. An acceptable record would undoubtedly still require the full suite of plumage features to be confirmed, however. 

‘One unexpected confusion species comes in the form of Horus Swift A. horus, an African species believed to be largely sedentary. However, a recent mystery swift with a white rump seen in the Netherlands in September 2019 is currently being assessed by the CDNA, and Horus seems a realistic possibility https://www.dutchbirding.nl/dbactueel/1558/de_schierzwaluw_stand_van_zaken. A similar outcome has also been suggested by some for the 2002 Dublin bird. Recent observations in Senegal have established that Horus Swift occurs in the north of the country, close to the border with Mauritania – a pretty incredible leap of c. 1,600 km from its previous known range https://senegalwildlife.wordpress.com/2018/04/10/those-mystery-swifts-horus-new-to-senegal/. Perhaps Horus Swift may be prone to larger movements than previously thought, and this adds another to the swift watcher’s radar when it comes it identifying one of these high-speed mini-albatrosses of the continents.’

James Gilroy, BOURC Chairman, commented: ‘As detailed above, there are multiple recent records of this species in northwest Europe, indicating that, despite its relatively small population size in southern Europe, it is a very plausible natural vagrant to Britain. BOURC was satisfied with the identification, and had no doubts that the bird was of wild origin, given that the species is not currently known in captivity. The timing, location, appearance and behaviour of the Hornsea Mere individual were all consistent with natural vagrancy – the late autumn occurrence falling in line with two of the previous three records in Scandinavia.’

 

Volume: 
Issue 3
Start Page: 
171
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