02 May 2013 Langstone Harbour and Oysterbed Lagoon report by Chris Cockburn

Hello folks

Lots of black-headed gulls are now on nests on the two islands in the Oysterbeds lagoon; but some have already had to re-nest following tidal flooding!  Unlike the five harbour islands and the harbour’s beaches, the two lagoon islands do not have tidal strandlines and, therefore, the birds have no useful indications for apparently safe nesting areas.

In a first for the site, Mediterranean gulls are nesting on the East Island (perhaps it should be called Banana Island, given its shape in plan-view). Mediterranean gulls seem to prefer well-vegetated nesting sites and this year East Island does have some perennial vegetation (Sea Couch and Sea Beet) – despite my hope that vegetation clearance would happen. So, watch out for grey chicks as well as the brown black-headed gull chicks.

Sandwich, common and little terns have been roosting on the Stoke Bay shingle spit at high tide and at least two pairs of common terns & one pair of Sandwich terns have briefly roosted on East Island.

100 tons of graded shingle has been ferried out and graded on the western end of a bund (the “NW Bund” that forms the northern edge of the lagoon) – it is hoped that little terns will nest there (they have used that area in past years). The imported shingle might also attract nesting oystercatchers and ringed plovers.

Four little tern decoys have been placed on a vegetation-cleared area of the “North Spit” (an ‘island’ north east of the lagoon); yet another potential little tern site.

It’s fingers-crossed that Bob Chapman’s designed little-tern raft will prove successful (it will be placed in the Deeps at Farlington Marshes LNR, which is managed by the Hampshire & IoW Wildlife Trust).

There are now five potential little tern nesting sites in the harbour – if all of them are used, even if only by a few birds, there is a much better chance of at least some productivity instead of total failure when all of the birds nest at the same location and predation or tidal flooding occurs.

The gull-nesting season on the harbour islands (South Binness, Round Nap & Baker’s Islands) has only just started, one of the latest starts ever and possibly because of frequent presence of large raptors. Adult female and adult male peregrines have been observed roosting on Round Nap Island and today there were two major disturbances (early this afternoon, a buzzard was using the thermals rising from South Binness and this evening, most of the gulls on South Binness abandoned their nests from at least 19:30 to 20:20, possibly because a raptor was enjoying a meal on the beach).

The high tide roosts at Stoke Bay are worth watching; recently summer-plumage dunlins, sanderlings, knot, bar-tailed godwit and greenshank have been recorded.

At the Oysterbeds, insects have at last become more noticeable (bumble bees, flies, butterflies and even swarming insects today) and plants are burgeoning after the long and dreary ‘winter’.

PS BBC Countryfile will be showing a snippet about the Oysterbeds on Sun 12 May.

PPS It would be really appreciated if some of you could spare some of your valuable free time to help by volunteering with RSPB by greeting visitors at the Oysterbeds. Alison, Emma and Ian – I do hope that you can help again.


Chris C

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