Pacific Swift (BBRC)

One fortunate observer was in the right place at the right time to see and photograph the sole county record at Saltfleetby-Theddlethorpe NNR on June 12th 2013. The bird had earlier been seen moving slowly south over the Spurn peninsula, Yorkshire, before being lost to view there at 08.50h. It reached the Saltfleetby-Theddlethorpe reserve at 15.20h obviously having continued to move only slowly south after it had left Spurn. This astounding observation proved to be the 7th British record. When the 2013 records were examined by BBRC it became clear that all four records of Pacific Swift in 2013 most likely related to just one individual roaming from Suffolk to Yorkshire, and back to Suffolk via Lincolnshire over a period of 19 days. Away from Britain, all European reports of Pacific Swift fall between May 10th and August 19th. In Sweden, the repeated occurrence of an individual at the same inland site on May 15th, 2013 and on May 10th–11th and May 30th, 2014, gives support to the theory that vagrant Pacific Swifts may well return to Europe in subsequent years. It would be nice if the next county record hung around for a bit longer.

Finder’s report: Pacific Swift at Saltfleetby-Theddlethorpe NNR, June 12th, 2013, first county record

by B. M. Clarkson

Note: This account is based on the account which first appeared in the Lincolnshire Bird Report 2013. The BBRC report for 2013 hypothesised that all four records of Pacific Swift in 2013 were just one individual roaming from Suffolk to Yorkshire, and back to Suffolk via Lincolnshire over a period of 19 days but acknowledged that this was little more than educated guesswork. Furthermore, they speculated that the bird that flew over Spurn on June 12th, 2013, could have been the same individual recorded there on July 1st, 2005, on June 22nd and 26th, 2008, and again on July 9th, 2011 - after all, the longevity record for one of its congeners, Common Swift A. apus is nearly 18 years of age (BTO Online Ringing Report).

Circumstances

On Wednesday June 12th, 2013, I had intended to walk from Donna Nook to Seaview Farm, Saltfleetby. After hearing of the significant occurrence of a Pacific Swift at Spurn earlier in the day, which was observed feeding over the Triangle while slowly moving south and which passed the Warren at 08.50 hr., this plan was abandoned, and I decided to concentrate on a smaller area. At 12.30pm I took a steady walk from Sea View Farm to Rimac (Saltfleetby-Theddlethorpe NNR). It was pleasantly warm, and despite the earlier event at Spurn, I decided not to go overboard about it and enjoy the day. At Rimac two Hobbies were in the area and along the east track north to Paradise Poll, Swift and House Martin numbers had built up and were everywhere in moderate numbers. A third Hobby flew south from Paradise Pool and then, as if to direct one’s attention, another Hobby flew through south from Saltfleet pointing the way to concentrations of aerial plankton! With the ‘hub’ centred to the south from I reverted to the Sea View Farm area; en route, people out for the day commented on the Swift numbers. At 2pm as the sky was darkening inland over Saltfleetby St Clements with a strengthening westerly wind it was notable that there was an increase in Swifts flying in from the sea.

At 15.20hr. I walked from the coastal track at Sea View up the path to stand on the west side by  the pillbox in the dunes (TF46436 92453) and after checking my camera settings I settled down to watch the House Martin and Swift movements. After watching a Common Swift tacking its way into the offshore winds from the tideline up to the dune system with all the others feeding over or just above the saltmarsh vegetation, I turned my attention south and immediately found myself looking at a larger more rakish swift with an unmissable gleaming white rump, why? Because the upperparts were very dark, if not deep black! The flight was more gliding lacking the flicky action of the Common Swifts. As I checked the tail it was noticeably long and deeply forked, and also more substantial than Common Swift, with the white of the rump gripping the rear flanks, a feature which was very easy to see. As it banked into Sea View pullover revealing the barred underbody, I took a few images the camera focused and then immediately lost focus as I pressed the shutter (one of those  irritating refocus adjustments). Realising that the bird was  most likely a Pacific Swift as it flew west up and over the car park, I changed position 15 ft. to higher ground in an attempt to relocate it. This was surprisingly easy (no binoculars needed). Here, it had turned north to fly almost directly over me, the focusing system on the camera allowing me two shots before it  turned to the west. More shots were obtained as it moved away towards Sea View Farm before it reached the west side of the dune slope, gradually altering course to c. NW. I continued to watch it fly high over the English Nature compound with Common Swifts along a tree plantation strip feeding low over the trees with 40+ Common Swifts and several House Martins.

As the cloud base dropped some birds flew inland across the road to feed over a cattle field and eventually disappeared into the distance. A quick perusal of the snaps revealed two classic barred/mottled underpart shots of a typically worn bird, clearly a Pacific Swift, A. pacificus. Intending to relocate the Pacific Swift I walked north, but as I approached the kissing g ate (and a Nightingale burst into song on the east side of the dune bank by the gate) I realised that would be a step too far and that a few more eyes would be needed. As I retraced my steps a 2CY Red Kite flew south within 30m of me as I continued onto the Great Eau bridge at Sea View and from where I had a clear view over the area 1.5 miles to the NW and NNW. Common Swifts and House Martins could be seen flying low over the trees from Gowt’s Farm south to a small bungalow by the river. Some swifts flew across the road to a pasture with cattle in, although throughout this time the sky darkened with the threat of impending rain. A few swifts filtered south whilst maybe the 4th Hobby of the day flew north. I couldn’t relocate the Pacific Swift and not long afterwards heavy rain set in. The bird was not seen again.

The bird had been watched at distances of up to c.325 yd. over the saltmarsh, then down to c.10-15 yd flying over the dunes, and for 3+ minutes in total. Weather was bright sunlight but flat and duller later with increasing cloud from the west. I was using Swarovski EL 8x32 binoculars. The sex and age of the bird was not determined.

Description

Head - crown and nape blackish, hind neck blackish brown, sides of neck very dark brown, feathers finely fringed off-white. Ear coverts slightly paler brown and with blackish eye patch. The tract of feathers from chin sides directly below the eye patch and ear coverts off-white in flat light but in stronger light appeared whiter though as bright as the chin. Sides of throat and lower throat paler, mottled versions of the sides of the neck. Chin and upper throat off-white with sparse mottling in flat light but appeared clean white in stronger light.

Upperparts – back and mantle black, rump and rear flanks pure white which extended a little narrowly onto the rear of the flanks just below the back end of the wing. Area of white approximately rectangular, gently curving around onto flanks. Uppertail coverts and tail equally black with undertail paler.

Tail – plain dun brown with darker shafts, deeply forked with each fork broadly based giving the tail a heavy appearance when spread, making the tail look very long. On reviewing the images, I noticed that when the tail was closed it appeared to be held flexed slightly up or down.

Underparts – flanks and belly thick, buff bars, washed coffee-cream across the central breast leading to a paler flank and belly area separating the dark neck sides from the paler parts of the head. Five alternating dark brown and brownish-buff barring to a central point midway along the flanks. The pattern in reverse comes from the leading edge of the vent and meets like two ripples in a pond across the central belly; on the flanks these two sets of bars are separated  by a small triangle of off-white. Vent and undertail covert patterning consisted of straight dark brown bars with some broader brownish-buff barring.

Underwing – remiges showed dark shafts, very dark sub-terminally with small off-white tips in good light, often barely visible; inner web had a translucent wash of light brown; axillaries dark brown; underwing coverts darker than remiges but paler than axillaries.

Reference

Clarkson, B (Undated). Pacific Swift Apus pacificus. Lincolnshire Bird Report 2013,167-169.