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 www.bto.org/ras-results

Auk Chicks

As a seabird colony, Skomer sees a huge influx of birds in the summer, with the vast majority of the seabirds only hoping to raise one chick in the year, if everything goes well.


Adult Guillemots and Razorbills preen and bond a the beginning of the season. (Photo P. Reufsteck)

Pufflings

As if puffins weren’t charismatic enough, their chicks have the adorable name ‘Pufflings’. Those lucky enough to be in the right place at the right time have had glimpses of these young birds coming to the entrance of their burrows to stretch their wings and build up flight muscles, before retreating below ground to await more deliveries of fish from their parents.


This brave Puffling emerged from its burrow at the wick to stretch it's wings last week, and has most likely now fledged. (Photo by one of our weekly volunteers, Allan Rose)


The rest of the pufflings journey however is a lot harder to follow, with the pufflings only finally leaving the burrow and fledging out to sea after complete darkness. If they survive their first winter, they will return next summer, after the breeding adults have already got eggs or chicks down their burrows and watch what’s going on. This social return is thought to be why Puffins are often slow to colonise new areas.


If you get a good enough look at them, or have a decent quality photo you can tell these youngsters by their slightly darker bills with fewer grooves.



If you look closely, you can see the bird in the left photo has few if any groves on its bill, compared to the bird in the right photo, which is a breeding adult.

Jumplings

Razorbills with a young chick. (Photo P. Reufsteck)

The first guillemot chicks hatched on the second of June and the first Razorbill on the 28th May. For both of these Auk species, chicks stay on the cliffs protected by an adult until when they only a third grown (sometimes as young as 15 days old), head out to sea. One of the adults (normally the male) goes down to the water and calls the chick, which calls back with a characteristic high pitched call, and eventually, during the evening it jumps off the cliff. This is where they get their name from. They do this before they are big enough to fly, and their wings can only slightly break their fall. If they survive the jump and make it to the water, they then have to make it to their parents before a gull makes it to them. Once safe from the immediate danger, the male will take them out to sea, where they will continue to feed it away from the dangers of life on the cliffs.


Similarly to Puffins, young birds return to the island when they are a few years old, but they generally don’t begin breeding until they are five to seven years old. Thanks to long term ringing studies like the one run by Tim Birkhead of Sheffield University, we are able to know in amazing detail the life history of some of our birds. For more information click here.


A guillemot chick on one of Skomers cliffs, being protected by an adult. this bird would probably have only stayed on the cliff a few more days before jumping. (Photo P. Reufsteck)

All being well the majority of our chicks will return to the island in a couple or three years’ time, and start breeding themselves a few years after that.

Good luck to them all!

Sarah (assistant warden)