Friday, 17 August 2007

Climate change linked to UK bird declines

A new report from UK conservation bodies suggests that many UK wintering bird population declines may be due to climate change.

The State of the UK’s Birds 2006 examines bird population trends, highlights some long-term declines in the populations of many regular winter visitors, including the Greenland and European populations of White-fronted Goose (-63%), Shelduck (-20%), Mallard (-32%), Pochard (-23%), Ringed Plover (-14%), Dunlin (-15%) and Turnstone (-13%).

The precise reasons for the decline of each species vary, but a common theme appears to be climate change. As winters become milder both in the UK and elsewhere, it appears that some birds are not flying as far as the UK to find suitable conditions: this trend has been particularly noted in Northern Ireland with declines of Pochard and Bewick's Swan (-62%).

Dr Mark Avery, the RSPB's conservation director, said: “The UK has had both the perfect climate and perfect habitats for these birds, but the evidence is growing that climate change impacts are starting to bite. Sea level rise and warmer winters are reducing their numbers, undermining our importance for birds.”

The report also highlights a doubling of the overall numbers of 39 species of waterfowl spending the winter in the UK in the last three decades. The populations of some species, notably wading birds including the black-tailed godwit and the avocet, have increased markedly since the late 1970s but this is largely as a result of conservation action.

Some rare breeding birds have done well with 357 pairs of Little Egrets and 241 pairs of Mediterranean Gulls in 2004. Since their peak in the 1980s, Golden Oriole numbers have fallen but appear to be stable at about 8-11 pairs since 2001. Repeat surveys of the breeding birds of the South Pennines, Isles of Scilly (seabirds) and Lewis Peatlands also show some fascinating changes.

As well as looking at bird within the UK, the report also focuses on the birds of some UK Overseas Territories. A survey of the breeding birds of the Indian Ocean Territories (Chagos Archipelago) shows huge declines in some seabirds between 1996 and 2006: Audubon’s Shearwater -69%, White-tailed Tropicbird -46%, Masked Booby -67%, Roseate Tern -80%, Bridled Tern -60%, Brown Noddy -78%, Lesser Noddy -91%. These may be simply a shift in breeding distribution as there were massive increase in Brown Booby (+2262%), Lesser (+181%) and Greater (+1267%) Frigatebirds.

The State of the UK’s birds 2006 is produced by a partnership of three NGOs – the Royal Society for the Protection of Birds (RSPB), the British Trust for Ornithology (BTO) and the Wildfowl & Wetlands Trust (WWT) – and the UK Government’s four statutory nature conservation agencies – the Countryside Council for Wales (CCW), Environment & Heritage Service (Northern Ireland) (EHS), Natural England (NE) and Scottish Natural Heritage (SNH).

* A free copy of The State of the UK’s birds 2006 is available with the September issue of Birdwatch – available from newsagents now *

Photo: Ringed Plover by Steve Young (