Thursday 7 July 2011

Spoon-fed

Feeding Spoonbill pictures taken by John Bottomley at Titchwell. 

The Wadden Sea islands are remarkable for both migrant and breeding birds. Texel, at the southern end if the chain, is perhaps the best known to birders and has high levels of conservation management involving terns, waders, plovers and Spoonbill.

One key fact is that the island has virtually no mammalian predators, just a few Stoats. This was clear at our first stop; a Sandwich Tern colony of some 1200 pairs, on easily accessible spits and islands but full of chicks. The next stop was one of two Spoonbill colonies on the island, one amongst scrub, the other in saltmarsh, but both on the ground.

Spoonbills have been increasing in the Netherlands since the 1980s. There was an expansion into the Wadden Islands after the colonies at Oostvaardersplassen moved when the site was dried out for some years. The two colonies appear to feed principally on different food. The 'scrub' colony feeds on sticklebacks, with birds foraging principally on the Dutch mainland many miles away. The saltmarsh birds feed on prawns in the Waddensea. The Dutch have developed specialised sluices to allow spring-running Three-spined Sticklebacks to enter freshwater from the sea. This forms a key early food for Spoonbills, as discussed in a previous blog. Prawns increase in size and abundant later in the season and thus the saltmarsh colony breeds later.

So what do we need to get Spoonbills established as a breeding bird? A large wetland nesting site, secure from predation and disturbance, and large food-rich shallow wetlands. Birds may travel many miles between these sites.

Wandering on through dunes we saw numerous Bluethroats (60 pairs on Texel), Bittern (5 boomers in dune pools), abundant Marsh Helleborine and Fen Orchid of the subspecies ovata, with its more oval, hooded and erect leaves. Kentish Plover previously nested here but are now declining in The Netherlands, with the population down to c200 pairs, mainly in the delta region. The habitat looked good and was extensive but human disturbance is a problem.

A newly created scrape held many Little, Common and Arctic Terns, as well as 100+ pairs of Avocets. With increasing pressure on beaches, this is exactly the sort of conservation action that is required for our terns. Nearby we looked over a saltmarsh wader roost, holding 10,000+ each of Curlew, Oystercatcher and Knot, and 20,000+ Bar-tailed Godwits.

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