16 Dec 2008

10th Dec 1988, Santoña Marshes

West of the industrial region mentioned above there are rivers which flow from the mountains to the sea in a clean state; and the marshes and estuaries they form are of immense importance to wildlife. Three fairly short rivers flow into the bay at Santoña and Laredo, and saltmarsh is creep­ing onto the mudflats exposed at low tide. Shelt­ered from Atlantic storms by the limestone massif of Monte Buciero at the harbour mouth, the bay attracts sun‑seekers in summer and flocks of migrant wildfowl and waders in winter.

Spoonbills stop here on migration, and shelduck also are said to have taken a liking to the place in recent years, though there are none to be seen today. The marshes are the principal site on the north coast for grey plover, dunlin, greenshank and curlew. The most numerous species that we see is wigeon, there are thousands settled quietly on the water.

The map shows a minor road crossing the marshes ‑ two lanes with crumbling edges, no stop­ping places and fast Spanish traffic. We park at the Santoña end and walk back. About half way along there is an area surrounded by a dyke and partly drained, it has a few healthy-looking ponds and willow scrub in the wetter part, while the drier area comprises a small eucalypt plantation. The trees are regenerat­ing, but there is no under-storey since the ground is carpeted with slow-decomposing eucalyptus leaves which inhibit the growth of other species.

Eucalyptus was introduced to Europe in 1804, within a few years of the discovery of Australia, and was soon found to grow well on deforested land where the soil was so thin and badly eroded that few other tree-species could find sufficient sustenance. Throughout the nine­teenth century it spread on eroding, near-desert lands around the Mediter­ranean, serving as windbreaks, providing welcome shade and stabilising the soils. It is only relatively recently that its use in forestry has become important, the wood is ideal for pulping to make paper, and on less impover­ished soils the trees grows very quickly.

Like most introduced species, the eucalyptus has a reputation for being no good for birds: however we find that the few small birds here are hidden by the large ever­green leaves.

While the tide is low there are a number of people out on the marshes, variously fishing, digging or probing for whatever is there. We watch a couple of fishermen under a bridge. They have a wok‑shaped basket on the end of a rope. It is baited with a sizeable piece of fish and, with the aid of a forked stick, lowered vertically into the water and laid on a ledge or mudbank. After a few minutes it is slowly pulled out of the water and the catch ‑ crabs and crayfish ‑ is emptied into a wicker basket.

Today is grey and murky with neither wind nor sun, but some drizzle in the afternoon. The tide is coming in and bringing with it a juvenile red-throated diver and an adult great northern diver which we are able to study at much closer than usual quarters. The red‑throated looks small and finely built compared with the heavy angular great northern. The latter swims mostly in a hunched posture, but then preens, and finally goes fishing. For this it swims around with its head and neck stretched along the water surface, then dives, sometimes coming up with a crab.

Four red-breasted mergansers fly in and spend most of the time vigor­ously stirring up the mud and shallow water. Eider and scoter also move up-stream, some of the female and juvenile scoter looking almost chestnut in colour.

An adult Mediterranean gull roosts on the mudflat, then becomes active as the tide disturbs it. It walks a few metres and picks up an amor­phous lump from the mud, takes it to a nearby puddle and washes it thoroughly several times, then shakes it vigorously for a few seconds before swallowing it whole. This species' winter diet consists mainly of molluscs and marine fish.

Two little egrets fish close to the shore, one moving slowly and deliberately, stirring up mud with its foot, the other more energetic, rushing from side to side and flapping its wings to dis­turb prey. The first one seems more successful. Later a dozen egrets join a feeding frenzy of gulls, cormorants and herons, then at high tide roost with the latter two species on a half submerged wreck.

Among the waders common sandpiper and whim­brel are of particular note as we were now in their wintering areas. Some of the bar‑tailed godwit have cinnamon plumage on their necks, breast and scapulars indicating they are juveniles.

Out on the open channels, there are about forty black-necked grebe, roosting or preening. As the tide brings them in, they disperse into smaller groups and begin feeding. Often a group dive together, leaving the water empty. They are quite noisy, calling to each other with high pitched whistles. If a bird surfaced alone, it sometimes gets quite frantic, whistling loudly and paddling around to find its mates. Their rather contrasty plumage made the little grebe look quite drab.

A peregrine flies in, calling, and settles atop an electricity pylon to watch the world go by. We make our way back to the van through drizzle.

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