Little Swift at Barton pits June 26th 1998
On the afternoon of June 26th I was trying to mop up any outstanding broods of wildfowl to complete the annual breeding survey of the clay pits. Dodging the regular thundery showers I found myself sitting in the hide which looks westwards over Barrow Haven reedbed at about 14-30 hrs as yet another downpour threatened to engulf the local environs. Scanning across the pit I realised that the Common Tern, sitting on its nest on a brick pillar in the next pit to the west, about 700m away, was visible from the hide; at least it would save me the trouble of walking through 700m of wet grass to check on their progress. It was at this point that I realised there were good numbers of Swifts feeding low over the Humber embankment which borders the next pit, pit25, beyond the ski pit where the terns were nesting.
With over twenty years of regular summer swift scrutiny already having passed without reward, the news of three Alpine Swift fly bys at Spurn, in recent weeks, had inspired renewed swift watching but as usual to no avail. June 26th was not intended as a swift watching day but events suddenly took a turn swift-wards as a bird with a bright white rump literally flew through my scopes field of view at over 1km range. The view was so brief I initially suspected that I had glimpsed a House Martin in strange light and had missed the white underparts. The day was thundery, with dark brooding black clouds passing quickly north-eastwards, intermixed with bright sunny spells and some glaring skyscapes. A quick scan soon revealed the bird again; it showed a bright white rump and appeared to have a contrast of blackish belly and silvery underwings but in size it was difficult to judge just how big it was at 1km range, as it did not appear strikingly different to the swifts nearby although judging which individuals were close to it was hard enough at such a range and with such fast moving birds.
At this point panic set in. In my past swift studies I had located three swifts with white rumps, one with a white belly and a couple with a variety of white areas elsewhere in the plumage but this bird looked too precise and distinct to suggest an partial albino swift and its immediate jizz was more reminiscent of a Little Swift. I needed to get a closer view but the options were all fraught with problems and all relied upon the bird staying put which given the fast moving thunder showers and the rapid movements of swift flocks in association therewith, seemed hopeful at best. Of the three possibilities a run/walk along the 1km of bank would have left me one, exhausted and two having to walk that distance back plus more to alert other observers; driving 1.5 miles round to the next access point westwards would get me about 300m closer but take a good 5 minutes and driving right round to the location where the bird was feeding, a good 5 miles by road would take at least 10 minutes but would pass close to a phone box en route. Option two won and after a quick 200m jog back to the car I raced down the rough tracks to the ski pit access and quickly relocated the swift albeit still 700m away. At this range with a 30x scope however, I could see a broad white rump, short square ended tail and shorter more rounded tipped wings than the nearby swifts. I was convinced it was a Little Swift, not considering any similar African swifts, and thus set off on the 5 mile epic to get even closer. Calling at a phone box (this was pre-mobile phones) on the way I suffered a complete mental block on phone numbers and with just 30p in change got one answer phone, a very dippy pager operator and a BLNE answer phone where I left a message to the effect that I thought it best going out as a probable until I made 100% certain; shadows of large seagulls hung over the phone box. Eventually arriving by the sailing pit at about 15-10 hrs a desperate search failed to turn up any sign of the bird and 10 minutes later it had still not materialised. Then suddenly there it was low over the Humber bank, coming towards me in bright light backed by a black sky giving unbeatable views. It fed over the water on pit25 for about 20 minutes and then as the sun came out it began to climb with the swifts and I lost sight of it as it passed across the sun. At this point no-one I phoned had appeared and nothing had come on the pager so I begged the use of a phone in the sailing club and rang birdline. Again no response! I thus returned to the bird and failed to relocate it by 15-50 but then it again appeared over the pit where I watched it to 16-04 when it again disappeared. With still no response from any birders I decided to return home and ring round more people plus I had my daughter to collect from nursery and due to the mental block could not remember when!
Back home at 17-10 hrs a phone call came in saying the swift could not be found in spite of 30 minutes searching. I headed back down to the pits on my bike and just as I arrived it was relocated flying back in from the Barrow Haven direction. It was then seen almost continually with odd short absences until about 19-15 (I left the site at 18-40) when heavy rain set in for over an hour after which it was not seen again.
The number of swifts present on 26th was certainly higher than in recent days with over 500 estimated compared to about 300 over the last 2-3 weeks and it would appear that the Little Swift arrived with a mobile flock of common swifts in association with the thundery weather system affecting the area at the time.
The Marsh Warbler at Far Ings, Barton, May-June 1997.
Somewhat surprisingly given the successful nature of the early 20th century ornithologists, notably Caton Haigh, who bagged several rare species of warbler on the Lincolnshire coast, including the first British Greenish and second Lanceolated, there are no historical records of the Marsh Warbler in Lincolnshire prior to 1961 when one was trapped at Low Farm Tetney on October 8th.
The following record, a singing male trapped at Bardney sugar beet pits, stayed from June 14-22nd 1964 and set a longevity record for residence in the county which stood for thirty three years! This bird also fell into what quickly became established as a regular occurrence pattern of singing males arriving during early June as spring overshoots from their main breeding range on the near continent and in particular Scandinavia, where the breeding population underwent a rapid expansion from the 1960's. The following seven county records all occurred between May 28th and June 5th, a remarkably restricted period, with the exception of a very early bird at Theddlethorpe on May 17th 1980. All were found on the coast apart from two which were discovered at Messingham Sand Quarries from June 4th -10th 1983 and on June 3rd 1985. The first bird had located an area of suitable breeding habitat on the northern slope of the old sand workings where a growth of nettles and willow herb was set amongst invading sallow and willow scrub on the edge of a phragmites reedbed. The latter was far more unusual in favouring a small clearing, again with nettles and willow herb, but in the middle of a plantation of 5m high corsican pines. Autumn 1986 produced a well photographed bird at Saltfleetby on August 24th in a fall of Scandinavian night migrants and further late autumn birds followed at Chapel Point from October 22nd - 23rd 1988 and at Skegness on October 16th 1993. The spring of 1992 proved to be a classic period for the occurrence of Scandinavian overshoots with regular periods of south-easterly winds from mid May to mid June. Not surprisingly several Marsh Warblers appeared on the east coast with a record 35 in Shetland. Following a singing bird at North Cotes on June 7th the first for Barton pits was a singing male which took up residence in the Humber Bridge viewing area pit from June 8th - 10th. Again it had found a piece of suitable habitat with nettles and willow herb growing amongst some stunted dead elders on an island surrounded by phragmites. In spite of regular searching after the 10th this bird was not relocated and thus the appearance of a singing male in the scrub by the pursuits centre track on June 16th most probably involved a second individual especially given the large number of birds arriving on the coast at this time. The most recent Lincolnshire bird prior to 1997 was a bird singing briefly at North Cotes from May 24th - 25th 1994 in the same bushes frequented by another Scandinavian overshoot a male Rustic Bunting.
The spring of 1997 was a poor one for observers of bird migration which meant it was a good one for the birds which were undertaking the migrations! Long periods of high pressure enabled birds to navigate successfully and arrive back on their breeding grounds without displacement. A count of singing male warblers around the Barton-Barrow Haven pits over the period May 15th - 17th produced totals of 353 Reed, 98 Sedge, 80 Willow Warblers, 90 Whitethroats and 35 Blackcaps indicating a good arrival of summering birds with only Lesser Whitethroat at a mere 12 males being well down in numbers. Further sample counts during late May however, showed that a later arrival had increased numbers considerably in the latter days of the month with up to 20% more Reed Warblers present in some areas, 100% more in one pit, and a few more Sedge, a late increase in Lesser Whitethroats and a new Grasshopper Warbler also arriving in Westfield Lakes on May 30th.
At 05-35 hrs on May 31st while crossing the south meadow from the car park at Far Ings I heard a few fluty notes followed by a rapid musical chatter. It sounded a bit Marsh Warbler like but not very loud. Could it be a newly arrived Reed Warbler mimicking? A return to the car park however, quickly revealed the songster perched in full view on the burnt-out front of a large hawthorn in the adjacent reedbed. Being closer to the bird its full very distinctive song rendered it easily identifiable and good telescope views established that it showed the relevant structural and plumage criteria.
The bird, presumed to be a male, but both sexes sing, had adopted a territory based on the large hawthorn with a periphery of burnt off brambles and resurgent nettles and willow herb set in amongst a phragmites reedbed with some old dead stems and a luxuriant growth of new green reed. For the first three days of its residence Marshy sang almost constantly with short breaks to go down into the surrounding vegetation no doubt for necessary sustenance. It sang from exposed perches high in the bush, often on top, and provided a steady stream of observers with superb views although many seemed unable to hear its superb song! It was still singing strongly at 00-33 hrs on June 1st when its quick fire renditions could be appreciated from the visitor centre over the odd can of lager! It certainly appeared to be holding a territory and was noted seeing off Reed Warblers, Blackcaps and Sedge Warblers from its favoured bush. From day four June 3rd, with increasing winds it became less obvious during the day time with long absences from its song perches but it was still singing strongly in the early mornings between 04-00 and 06-00 hrs at least. It now sang more frequently from lower perches in the brambles and reeds and less from the hawthorn.
Marsh Warblers are known to be incredible mimics and will copy the songs and calls of a wide variety of other species. On June 5th in the early morning 05-30 to 06-00 hrs I attempted to identify the species which Marshy was mimicking. I managed a total of eighteen species and I am sure there were others but at times it is sometimes difficult to know whether you are listening to the Marsh Warbler or the real bird; they are that good. The following were picked out; Blackbird, Song Thrush, House Sparrow, Magpie, Tawny Owl, Common Tern, Nightingale, Blue Tit, Great Tit, Sedge Warbler, Reed Warbler, Blackcap, Willow Warbler, Goldfinch, Chaffinch, Starling, Swallow, Greenfinch. Some of the species like Blackcap, Blackbird and Common Tern were represented by alarm calls only. Of interest was the reaction to a female Blackcap which approached the singing Marsh Warbler on the top of the bush. Turning to face the Blackcap in threat posture it uttered a fine rendition of Magpie calls no doubt intended to be more intimidating than its own calls!
Identification of a singing Marsh Warbler is relatively straightforward but note that Blyth's Reed Warbler's song is quite similar and it is also an expert mimic. Apart from song the Far Ings Marsh Warbler displayed the following structural and plumage characteristics which identify it from Reed Warbler. Long winged appearance created by eight pale tipped primaries visible beyond the longest tertial; contrasting wing with dark centres and pale fringes to tertials and dark alula with narrow pale fringe, the darkest part of the wing. Rounded head profile with spiky rear crown when singing and pronounced jowl. Short but obvious white supercilium which bulged slightly before the eye and faded quickly behind the eye; notable pale eye ring. Distinct olive tone to whole of upperparts in sunlight with slightly more buffy rump. Silky white chin and throat contrasting slightly with pale buff wash across upper breast and along flanks. Stout blunt tipped bill mostly yellow with dark ridge to upper mandible and a dark tip to underside of upper mandible tip when singing. Bright orange inside to bill and gape, open wide when in song. Pale straw coloured legs and feet. Iris mid brown.
By June 7th the Marsh Warbler became very elusive and could easily have been overlooked. It moved its location slightly to the periphery of a patch of willow, hawthorn and bramble scrub on the edge of the reedbed, and appeared to have ceased singing. A singing Reed Warbler had also moved into the same area and another pair of Reed Warblers were nest building in the Marsh Warblers original territory. Late on the 7th and early in the morning of the 8th however, I was convinced that I heard very brief snatches of Marsh Warbler song amongst that of a Reed Warbler. Was the Marsh Warbler doing a perfect mimicking job of a Reed Warbler or had a Reed Warbler managed to copy some of the Marsh Warbler's song? With less wind and a cooler morning on June 9th I positioned myself in a spot from where the Marsh Warbler's territory could be observed and from 05-30 hrs stood and waited. Again very brief snatches of Marsh Warbler song appeared to be coming from its new location along with regular Reed Warbler song but no bird was visible. While watching the pair of Reed Warblers nest building in the reeds adjacent to the hawthorn a third bird started to chase them and then followed them around. At one point it broke off perched up on a dead reed and sang well. It was undoubtedly the Marsh Warbler. The song and all the plumage features were clearly heard and seen. What appeared to be happening was that the male Reed Warbler was singing occasionally and the Marsh Warbler chipping in with odd notes and very short song bursts while following the pair of Reed Warblers. It did not seem to have a mate but was obviously interested in the female Reed Warbler! Following a few days with little attempt to ascertain if the bird was still present, on the evening of June 18th it was heard singing well from the hawthorn scrub adjacent to its initial territory where a Reed Warbler and Blackcap were also in song. Given that the Marsh Warbler had apparently ceased to sing on a regular basis however, it was impossible to ascertain just how long it stayed at Far Ings but it became the longest staying bird of its species in Lincolnshire.
Graham P Catley
