Shelducks and waders in decline

ACCORDING to Waterbirds in the UK 2012/13, a report just published by the British Trust for Ornithology, the populations of some duck and wader species are declining. Birds don’t recognise political boundaries and wetland ones are great travellers.

Those visiting Britain are largely the ones which come here. The report, based on synchronised counts, is therefore of particular interest to us. BirdWatch Ireland, supported by the National Parks and Wildlife Service, carries out similar surveys.

Shelduck numbers are causing concern in Britain. According to the Waterbirds report, fewer shelducks are spending the winter in the UK.

Numbers have declined by over a third in the last 15 years and are now at their lowest in four decades. This big white duck, with a dark green head and a brown sash across the breast, frequents estuaries, and nests in rabbit burrows. Each autumn, British and Irish ones, leaving their ducklings behind in the care of ‘aunties’, head for the Heligoland Bight on the German coast or Bridgewater Bay in Somerset. There they shed their flight feathers and grow new ones. Some pairs remain away until spring.

Meanwhile, shelducks from mainland Europe, having moulted in Heligoland, come to Britain and Ireland for the winter. According to the recently published Bird Atlas, the UK breeding population is holding its own but with fewer winter visitors. Counts in the Netherlands and Germany reveal similar declines there.

According to Olivia Crowe and Chas Holt of BirdWatch, shelduck numbers here fell by 19.5% between 2006 and 2011. Pairs have moved inland in Britain and the numbers breeding away from the coast have increased in recent years. This doesn’t seem to be happening here; Irish shelducks seldom nest inland, although there’s an established population around Lough Neagh.

The pintail, an elegant discretely-attired duck, may also be in trouble. Small numbers breed in Britain, mainly in Orkney. Birds from northern Europe visit UK and Irish estuaries in winter. Their numbers, according to the Waterbirds report, have fallen by 50% in the last 25 years. The Netherlands wintering population, however, has increased. The missing UK birds may be going there, the report suggests. Is this species shifting its allegiance to Europe? Irish pintail numbers seem to be fairly stable.

The report’s findings on waders are alarming; the wintering populations of eight common ones are declining. There are 39% fewer ringed plovers than there were a decade ago. These little brown and white birds, with black bibs, nest on coastal beaches, vulnerable to gales tides and disturbance. Although Irish ones have taken to breeding on cut-away bogs in the midlands, the species range here has contracted by 23% since 1972.

The number of curlews nesting in Britain is down 17% on the 1972 figure, although the situation is not as catastrophic as in Ireland which has seen a drop of 78%. According to BirdWatch, most of our losses occurred in the last 20 years; numbers fell by about 40% between 1994 and 2009.

Redshank numbers, down 26% in Britain since 2001, are at their lowest level in 30 years. So are dunlins, with a drop of 23%, and oystercatchers at 15%. But the news isn’t all bad. The number of black-tailed godwits has risen by 57% and the UK’s small population of avocets is up by 61%.

Ornithologists are at a loss to explain the declines. Climate change may be altering the winter distribution of ducks in Europe. Is it doing the same for waders? Are birds, which used to spend the winter here or in Britain, going to the Netherlands Germany or further east instead? Higher global temperatures could force pairs to move northwards to nest. In a changed habitat, they may find it harder to feed and raise their young. Do warmer conditions favour avian predators?

Nowadays, climate change is blamed for everything but is it the whole story?

nG. E. Austin et al. Waterbirds in the UK 2012/13. British Trust for Ornithology.