UK seabirds under pressure

Since 2000, the number of seabirds breeding around the UK has declined by over 600,000 or 9%, a report by the Joint Nature Conservation Committee (JNCC), the Government’s advisers on UK nature conservation, has revealed.

The recent decline follows years of poor breeding performance that have occurred with greater frequency since the mid 1990s and have been widely reported in the press.  “These latest figures on breeding numbers demonstrate the magnitude of the effect these poor seasons have had on the UK seabird population” said Dr Matt Parsons, one of the reports authors. “They represent a ‘turning of the tide’ for seabirds breeding in the UK, which increased in number from around 4.5 million in the late 1960s to 7 million by the end of the 1990s”. 

Recent declines have tended to be greater in species that feed on shoals of small fish, such as lesser sandeels. For instance, there are now 40% fewer black-legged kittiwake and 33% fewer European shags breeding in the UK than in the late 1960s.  Even greater declines have been seen at some of Scotland’s largest seabird colonies; Deryk Shaw, Warden of the Fair Isle Bird Observatory in Shetland said “Breeding kittiwake numbers have been falling for many years now and there was no reprieve in 2008. A whole island count found that the number of nests is only half of that counted as recently as 2005 with many birds just standing on bare ledges”.

The cause of these declines is almost certainly a shortage of food that has led to lower numbers of adults surviving from one year to the next, and not enough chicks being produced and surviving to replace them. 

The reasons for the shortages of sandeels in recent years are complex and not fully understood.  Over-fishing off eastern Scotland did have a significant detrimental effect on the productivity of kittiwakes at nearby colonies during the 1990s, but little fishing has occurred within foraging range of these colonies since then.  Fishing may be affecting the distribution and abundance of sandeels across the entire North Sea, but it is not clear whether this has affected the availability of sandeels to seabirds feeding closer inshore.  There is a growing body of evidence that sandeel shortages are also caused by increasing sea temperatures as a result of climate change.  Sea temperatures around the UK have been rising since the 1980s by around 0.2-0.9˚C per decade.  These rises are thought to have been responsible for striking changes in the abundance of plankton – the tiny floating organisms that sandeels and other small fish feed on.  

Long-term declines in numbers of black-legged kittiwakes and other species that rely on sandeels, are expected to continue unless the recent rises in sea-surface temperature are reversed. Reversing the recent warming of the oceans is reliant on the success of global efforts to combat climate change. However, in their report, JNCC identified two other man-made pressures – from fishing and from the introduction of non-native mammals to island seabird colonies - that could be managed in the short-term to mitigate the impacts of climate change.

For instance, the maintenance of an existing ban on sandeel fishing off eastern Scotland appears to have been effective by not exacerbating the existing impacts of climate change.

The eradication of non-native mammals that eat seabird eggs and chicks, from seabird islands  has resulted in the expansion of existing seabird colonies and in the re-colonisation by seabird species that previously nested there. On Lundy, in the Bristol Channel, rats were eradicated in 2004. Since then the seabirds have increased into new nesting areas. David Appleton of Natural England, said “Since we removed the rats, burrow-nesting species such as Manx shearwater and Atlantic puffin now have a safe home in which to raise their young.” The Manx shearwater population on Lundy increased from 166 pairs prior to the eradication to 1000 pairs in 2008.

As the 2009 breeding season gets underway, seabird biologists and amateur birdwatchers are currently monitoring events as part of the Seabird Monitoring Programme, eager to see what is in store for seabirds this year.

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Notes for Editors:

1. UK Seabirds in 2008 is a booklet summarising the results of the UK Seabird Monitoring Programme (SMP).  Led by JNCC, the programme co-ordinates the monitoring of seabird breeding numbers and breeding success throughout the UK.  Data from the Republic of Ireland is also collated, to set the results in a wider geographical context. Download UK Seabirds in 2008 booklet.
2. The following organisations are partners with JNCC in the SMP: Scottish Natural Heritage, Countryside Council for Wales, Natural England, Environment Agency - Northern Ireland, Royal Society for the Protection of Birds, Centre for Ecology and Hydrology, The National Trust for Scotland, The Seabird Group, Shetland Oil Terminal Environmental Advisory Group, BirdWatch Ireland, National Parks and Wildlife Service (Dept. of Environment, Heritage and Local Government – Republic of Ireland).
3. Much of the information of the SMP is collected by volunteers, some of whom are helped with expenses made available via the Seabird Group (for which, see http://www.seabirdgroup.org.uk/ ).
4. The Joint Nature Conservation Committee (JNCC) is the statutory adviser to Government on UK and international nature conservation. Its work contributes to maintaining and enriching biological diversity, conserving geological features and sustaining natural systems. JNCC delivers the UK and international responsibilities of the Council for Nature Conservation and the Countryside, the Countryside Council for Wales, Natural England and Scottish Natural Heritage. 
   
   

Further information:

General media enquiries should be directed to the (Peterborough): Tel: 01733 866839           

Fax: 01733 555948 

For an interview with the project co-ordinator, or answers to technical questions, please contact  (JNCC, Aberdeen): Tel 01224 655715

Images:

The following digital images may be obtained from JNCC Communications:

JNCC News Release 11/06/09