Hundreds of birdwatchers mounted an invasion of a remote Suffolk nature reserve at the weekend – forcing police to stage an operation of their own.

East Anglian Daily Times: John Richardson's picture of the Pacific seift at Trimley MarshesJohn Richardson's picture of the Pacific seift at Trimley Marshes (Image: Archant)

In the biggest mass arrival of twitchers seen in the county for years, birders from many parts of the country converged on the Suffolk Wildlife Trust’s isolated Trimley Marshes reserve, beside the River Orwell, to see a Pacific swift, a species seen so rarely in Britain that it is referred to in birding circles as a “mega”.

The nature reserve has a tiny car park near Searson’s Farm, Trimley St Mary, a long walk from the lagoons and grazing marshes over which the swift dramatically performed among hundreds of more familiar common swifts.

The allotted parking area quickly became full as the big ornithological news spread throughout the British birding scene on Saturday.

Birders’ vehicles were lined up in their hundreds along the nearby narrow stretches of Station Road and Cordy’s Lane and, following residents’ complaints, it is understood police officers attended to ease the chaos and control the traffic.

Officers were also in attendance again yesterday, when hundreds more birders arrived as news spread of the swift’s continued presence.

Originally reported on Saturday morning by local birdwatcher Johnny Rankin, the globe-trotting swift is thought to represent only the seventh or eighth British record of its species.

Its breeding range stretches from central Siberia eastwards through Asia to Japan, with wintering grounds in south-east Asia and Australasia.

An impressive master of flight, the swift is longer-winged than the more familiar common swift, with a brilliant white rump patch, a larger pale throat patch, scaly mid-brown underparts and a long, slim, deeply-forked tail.

Birders were divided over the swift’s travels in Britain. A Pacific swift was seen near Spurn Bird Observatory, at the mouth of the River Humber, on June 12, and was also seen a few hours later at Saltfleetby, Lincolnshire.

Some observers thought it likely that the Trimley bird was the same individual, while others said they could detect minute plumage differences.

The mystery may never be solved, and neither might another relating to the bird – was it the individual apparently seen over agricultural reservoirs at East Lane, Bawdsey, by one observer on May 29? That bird was inconclusively photographed but many observers are convinced that it was indeed a Pacific swift – and perhaps the much-celebrated star turn that attracted so many birders to Trimley over the weekend.

Wherever the bird had wandered in recent days, it certainly revived memories of the first Pacific swift ever to be seen in Britain – or even the huge biological recording area of the world known as the Western Palearctic.

That historic “first” came in Suffolk on June 19, 1981, when an exhausted individual that was found on the Leman Bank gas platform about 45 miles off Happisburgh, Norfolk, was taken by helicopter to Ellough Airfield, near Beccles.

It was released later that day after it regained strength and was seen the following day by just one observer over nearby Shadingfield.