…in Precipitous FallDramatic changes in the marine environment, particularly those fuelled by climate change, are believed to be responsible for the dramatic collapse in the numbers of one of the UK’s most engaging seabirds.
The numbers of the kittiwake – a dainty type of cliff-nesting gull – have more than halved since the mid 1980s across the UK, and populations in Scotland have crashed by almost two thirds.
Early reports of seabird nesting performance from this summer indicate continuing problems for the kittiwake population with one Scottish breeding colony now extinct and others predicted to disappear within three years. Counts of the average number of chicks per nest also seem to be reducing too. These declines are being linked to changes in the marine environment.Euan Dunn, is the RSPB’s head of marine policy. He said: “It now seems beyond doubt that the decline of the kittiwake is being driven by a slump in the availability of sandeels – a staple food for this and many other seabirds. It is almost certain that the crash of sandeels is linked to the warming of the sea and subsequent changes in plankton availability. In other words, changes at the microscopic level are wreaking havoc at the other end of the food chain.”
Although one of the world’s most abundant seabirds, kittiwakes are declining at an alarming rate, particularly in Orkney and Shetland where around one-fifth of the UK population return to breed each year.
Counts by RSPB Scotland and the Joint Nature Conservation Committee (JNCC) of Orkney’s ‘seabird cities’ revealed a staggering 82% decline in breeding pairs of kittiwakes in just over a decade. Populations on the Orkney mainland fell from nearly 11,000 pairs in 2000 to under 2,000 this year.
At Mull Head on the Orkney mainland, the once bustling cliffs were empty this year as kittiwakes failed to return to the colony to breed. The cliffs at Costa Head and Birsay held less than 200 breeding pairs while three other colonies hung on by a thread with fewer than 90 nests each- indicating possible local extinction within the next three years.RSPB Scotland’s Marwick Head nature reserve hosted most of the breeding kittiwakes with 1,134 pairs. However, numbers were 75% lower than in 1999, when there were 5,400 pairs nesting.
Doug Gilbert, RSPB Scotland Head of Reserves Ecology, said: “The counts this year are deeply shocking, especially the loss of kittiwakes at Mull Head. We know that kittiwakes in other parts of Orkney are equally affected, and to think of Orkney without thriving colonies of these fantastic birds is a sad prospect.”
Elsewhere kittiwakes are experiencing mixed fortunes. RSPB Scotland’s Sumburgh Head nature reserve, in Shetland, reported a poor year with only a small number of chicks fledging. In contrast, the kittiwake colony at RSPB Troup Head on the Moray Firth has experienced its best season in years with over 500 chicks fledging.
The Society’s Fowlsheugh nature reserve on the Aberdeenshire coast reported a halt in the long-term decline in kittiwake numbers. The colony had been in freefall – 20 years ago there were over three times as many nests, but the number of chicks raised in recent years is encouraging.
Euan Dunn added: “Seabirds remain largely unprotected at sea and have been marginalised in the identification of new Marine Protected Areas - this obvious gap needs to be filled if we’re going to prove we’re serious about protecting threatened marine wildlife. It is vital to maintain the current tight restrictions on the North Sea’s industrial fishery for sandeels to ensure it doesn’t add to the wider pressures on sandeel stocks.”
In other parts of the kittiwake’s range, there is evidence from Iceland, Greenland and Norway of its population declining.
In 2008, the kittiwake was added to an international watch list of threatened species, under the Ospar – Oslo-Paris – Convention, set up to protect the marine environment of the north-east Atlantic.
4th July 2014