Wednesday 1 July 2009

1000 Sandwich terns settle at Minsmere

Hundreds of threatened Sandwich terns nesting at Minsmere - But why?

June 2009. For the first time in more than 30 years, hundreds of threatened Sandwich terns have settled to nest at Minsmere RSPB nature reserve, on the Suffolk coast, joining record numbers of gulls to provide a spectacular sight and sound for visitors.
It is not known why the terns have suddenly returned to Minsmere, but as they arrived late, it suggests they may have moved from a site elsewhere, possibly in North Norfolk, following some unknown disturbance.


Nest in large colonies

Like most terns, Sandwich terns nest in large colonies. Their chosen nest sites, usually on coastal lagoons, islands or beaches, are easily disturbed, leaving colonies vulnerable and threatening the future of the entire UK population. Many colonies also relocate due to changes in fish populations, assuming they find somewhere else with suitable habitat and enough fish.


Mix with Black-headed gulls

Adam Rowlands, Senior Site Manager at Minsmere, said, "Sandwich terns are known for nesting among large colonies of black-headed gulls, where they benefit from the extra protection offered by the gulls against larger predators, especially big gulls. It is no coincidence that the terns have returned to Minsmere, with record numbers of black-headed gulls on the Scrape.


1700 pairs on the scrape"Minsmere's Scrape is a true seabird spectacle this year, with 1100 pairs of gulls, nearly 400 pairs of Sandwich terns and 190 pairs of common terns - the most since 1974. The sight and sound are superb - as many people who watched Simon King at a large tern colony in North Wales during the recent Springwatch series will recall. If you're lucky you might even spot a rare roseate tern or Mediterranean gull among them."


First time since 1978

Sandwich terns regularly bred at Minsmere until 1978, but only a handful of pairs have nested since then, until now. Suddenly, during the last two weeks, more than 1000 terns have arrived en masse on the Scrape, and nearly 400 pairs are now starting to nest on the shingle islands.


Little tern

Unlike their larger cousins, it looks like being a poor year for the scarce little tern, as only two or three pairs are nesting on the beach at Minsmere. After a good season last year, it appears these tiny seabirds have relocated farther north, with some nesting on the shingle beach between Dunwich and Walberswick, and good numbers settling within the main colony on Great Yarmouth's North Denes.


Adam Rowlands continued: "There are few more spectacular sights and sounds in the natural world than a large colony of nesting seabirds. The air almost echoes to the raucous calls of gulls and terns as adults return from fishing trips offshore clutching prized fish and sandeels for their mates, and later for their chicks. Why not visit Minsmere during the next few weeks to witness this spectacle for yourself?"


Sandwich terns
Sandwich terns are the largest species of tern nesting in the UK, being marginally smaller than the familiar black-headed gull. They have shaggy black crests and very pale grey wings, but are otherwise white. Their black beaks have a distinctive small yellow tip. There are about 12500 pairs at various colonies around the coast. Up to 750 pairs nested at Minsmere form 1965 to 1978, but apart form 23 pairs in 1995 there have only been occasional nesting attempts since then.


Sandwich terns are on the amber list of birds of conservation concern. This is due them having undergone a moderate (i.e 25 - 50%) breeding decline since 1969, and a localised distribution with more than half of the UK population found at 10 or fewer sites.


other terns
Common terns
, often known as sea swallows, are smaller, with a black-tipped red bill and black cap, but lacking the shaggy crest. They usually nest in smaller colonies around the coast, and also at gravel pits and reservoirs inland.


Little terns are tiny, barely larger than a starling, with bright yellow bills and a white forehead in front of their back crown. Only about 2500 pairs nest in the UK, exclusively on shingle beaches. The largest colony is in Great Yarmouth's North Denes.


All terns are summer visitors to the UK, and may be seen from April to September. They winter at sea in the southern Atlantic or off West Africa. They catch fish by diving into the sea from a height of several metres.


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