15th November 1988 - Zwin

The nature reserve at Zwin is the Belgian equiv­alent of Slimbridge, complete with wildfowl col­lection, tea room and refuge area. We dispense with the wildfowl collection and head for the refuge, and there the similarity to Slimbridge more or less ends.

The refuge comprises what was the mouth of the River Zwin before it was canalised, a 1.5 km line of sand dunes separates it from the sea; its other boundaries are dykes. A shallow creek, linking it to the sea at the eastern end, feeds a system of four brackish lagoons, though the whole area is often flooded at spring tides. The reserve itself is only 150 ha but it is surrounded by a 1500 ha buffer zone of coastal grass­lands.

Visitors are free to walk along the top of dykes in some places ‑ there are even seats and giant binoculars provided ‑ to look over the largest lagoon which holds various duck, geese and waders, though not in large numbers. The rest of the area is saltmarsh, where people are actually allowed to walk ‑ no hides or screens here! Access is limited only by an individual's desire to wade through mud and water, and, of the few that do explore, not many go very far off a single, rather wet, track across the middle of the refuge.

The birds are mostly the waders and wild­fowl one would expect for the time of year, except for a group of white storks on the marshy area. We view them sceptically, thinking they are probably pin­ioned birds from the collection, and anyway, storks are supposed to have migrated south by now. However it soon becomes clear that these are free flying birds, and inquiries reveal that the local popula­tion, some thirty to forty birds, are resi­dent. In fact, they are mainly descended from sick and injured birds brought to Zwin for treatment, and, having got used to being fed, they do not bother to migrate.

The storks seem to dwarf the herons, which are similarly numerous, so it is surprising to find they are only some 15 ‑ 20 cm taller and have a shorter wingspan. The stork's body is, however, rather larger than the heron's; and its striking plumage probably increases the effect of bulk.

Occasionally one or two take to the air, flying with the head and legs drooping somewhat below the body, and with each wing in a slight arch when viewed head on. At this angle the primaries stick out at the ends of the wings like untidy brushes.

Most of the storks have clean black and white plumage with red legs and bill, but a few are smudgy looking with finer, black‑tipped bills; these are juveniles and they will remain dis­tin­guishable until they moult in December.

The birds stalk slowly through the water, occasionally putting in a few long fast strides to reach potential prey items. Several times we heard some bill clattering, but the noisy birds are always out of sight so we can't watch the display that is said to go with it.

Amongst the other birds are about a dozen whitefront geese, which are quite tame and include some of the Russian race. Like the storks, they are descended from sick and injured birds brought to the reserve for treat­ment.

There is also a turnstone feeding along the edge of the channels, turning over goose droppings where there are no stones to turn.