Friday, 21 July 2017

The world of the Black-legged Kittiwake

Most people wouldn't believe it but the Black-legged Kittiwake is apparently the most common gull species in the world. I'm guessing that people are more familiar with the classic 'seagull' of seaside resorts, the Herring Gull, but there are, in fact, twice as many Kittiwakes in Britain than Herring Gulls. Those who have made a trip to Bempton or the Farnes on the east coast, one of the Scottish islands or indeed Skomer may be aware of this dainty seabird but their pelagic lifestyle and choice of breeding habitat - vertical rocky sea cliffs, often on remote coastlines and islands - take them away from the sphere of most peoples consciousness. Having said this, all is not well in the world of the Black-legged Kittiwake.

Adult Black-legged Kittiwake

Adult on nest with a day old chick
The UK currently has around 380,000 breeding pairs of Kittiwakes which is around 8% of the world population. They are red listed in the UK due to steep declines in the population since the 1980s. These declines are likely caused by low productivity coupled with low survival.

Kittiwakes need a plentiful supply of oily fish, such as sandeels, in order to raise chicks and during the non-breeding season to survive the winter and to be in good enough condition to breed again the following summer. Sandeel numbers are highly susceptible to overfishing and changes in sea temperature and a reduction in sandeel numbers, or their availability, will have a negative impact on Kittiwake breeding success. If you are interested in finding out more about the relationship between sandeel numbers and the breeding success of Kittiwakes (and Puffins) see these sites: marine-life 
and RSPB

Skomer has one of the largest Kittiwake colonies in Southern Britain and the largest in Wales. They have undergone several years of slow decline on Skomer and the 2017 total of 1,336 nests is once again a drop in numbers ( 9% less than in 2016 and 24% less than the mean of the previous ten years). Nationally, and especially in Scotland, the situation is even worse with declines of up to 15% per annum.

Work is being done on Skomer to monitor and study the Kittiwake population with the aim of identifying reasons for the decline and applying this to its conservation (although this may be very difficult given the broad scale nature of the problems involved).

The Wildlife Trust of South and West Wales conduct a whole island population count every year as well as productivity monitoring of a sub-set of colonies. Gloucester University undertake additional studies to look at adult survival. These studies cover population, productivity and survival but one missing link is knowing where the birds go to find food. Tracking work over the last two years by Liverpool University has started to reveal some interesting patterns. It seems that Skomer's Kittiwakes are island hoppers, feeding mostly around the local islands of Ramsey, The Bishops and Clerks, The Smalls, Grassholm and Skokholm and travel no more than 40 km from the colony on a single feeding trip. The study also revealed that the Kittiwakes prefered shallower, more vertically mixed, water, possibly due to higher resource availability in these areas. You can follow Alice Trevail and Samantha Patrick on Twitter at: @SEG_UL

All birds within the study are colour ringed to follow their life history
Threats: Climate change, warming seas, overfishing, increased storm events, pollution, mortality as bycatch, collision with offshore wind turbines.

Kittiwake nests at the Wick being battered by a storm in June 2017
Actions (taken from The IUCN Red List of Threatened Species):
The species could benefit from Species Action Plans, a regional monitoring strategy and further research on the effects on climate change and prey reductions. Creating a network of hunting-free reserves in coastal areas. Monitoring of bycatch of this species through on board observer programmes, and appropriate mitigation measures implemented where necessary. Sustainably manage fisheries to prevent over-fishing.

Obviously we can all help by reducing our carbon footprint and by making sure if we eat fish we source it and, other products, sustainably but there are also other small ways in which we can help. Supporting conservation organisations and research bodies who protect and study the lives of these vulnerable seabirds will give them a helping hand. If you are a keen birder, taking part in national and regional seabird surveys as well as making sure all of your seawatching data goes to Birdtrack will also help.

Let's keep them the most abundant gull in the world.    

Reasons for hope: A recent report by the BTO states that the Kittiwake is the only seabird within the RAS (Ringing Adults for Survival) network showing a long-term increase in survival. To read the full report see

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