Dominic Couzens On Twite

A hardy bird that has adapted well to the unforgiving environment of bitterly cold and windswept estuaries.

ONE OF THE great sights of birding is the mass of waders on an estuary, flying back and forth around high tide. There is something satisfying about appreciating how waders roost in large numbers when the tide is high, but go back on to the mud once the tide falls, and how different waders then spread out over different kinds of ooze. Over the years, I have been so overwhelmed by the sumptuous shorebird displays, that I tend to overlook other birds that are affected by the depth of water.

Several categories are: estuarine wildfowl, especially Shelducks and Brent Geese; cormorants and, to a lesser extent, gulls and terns. All these are wedded to tidal cycles. And then, how about a left-field addition to this list, a bird that you wouldn’t instantly assume was in such company – the Twite?

It doesn’t have long legs, or a long bill. But, in parts of its range, it is just as much an estuarine bird as the most committed Redshank or Dunlin. Rather than seeking out worms, crustaceans or molluscs in the mud itself, however, the Twite subsists on the seeds of estuarine plants that grow in patches regularly inundated by the tide, especially the Glassworts (Salicornia spp) and Seablite (Suaeda maritima).

The Twite feeds by hopping over the mud and perching on the plants themselves. However, it can only do this when the tide allows. As the water comes in, flocks of Twite feeding far out on the mud, usually without competition from other shoreline seed-eaters such as Snow Buntings and Shore Larks, are forced towards the inner saltmarsh. At high water, they will feed in adjacent fields, often flocking with these other birds, and even Linnets.