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Read by Charley and Dave
There are 6 major threats to our seabird colonies welfare and continued survival:
As we have seen before with the great auk many seabird species have long been persecuted by people throughout history devastating their populations. It is a decreasing threat thanks to laws banning the hunting of seabirds and their eggs, but is still prevalent in some places.
Some invasive species have very negative impacts on seabird populations as the seabirds have not adapted to cope with them. As we have seen before rats and feral cats are an issue on Alderney and controlling their populations can be very difficult.
Whilst our fishing vessels have provided some food for our seabirds by throwing discarded fish over the side, our fishing effort has greatly reduced the amount of fish available. So with less fish for our seabirds they have to go further to find food and struggle to raise their chicks.
As humans we like to live by the coast, where there is fresh air and the sea close by. But sometimes, building near the coast can damage the soil integrity causing more water to wash over the lands surface. This can erode coastal habitats and cause a lot of water to flow down cliffs making nesting very difficult for seabirds.
Perhaps the most devastating impact on seabirds is marine pollution. When oil is dumped at sea it gets into birds feathers stopping them from flying or hunting properly. The birds die from starvation and sometimes wash up on our shores in their hundreds or thousands, known as a 'wreck'.
As the world gets warmer in the summer due to our greenhouse gas emissions some species change their habits to cope. Algae that lives in waters of a certain temperature can only survive further north due to the warmer waters in the south. The fish that eat this algae follows it northwards, including sandeels. The seabirds then have to travel further to find their food and cannot cope with the extra effort.
One of our first seabirds to start fledging is the shag. We have colonies of these birds all around Alderney and its islets and recently we visited two of the to count how many chicks are ready to fledge: Little Burhou and Coque Lihou.
We went to Little Burhou on the 29th June and relocated all 36 nests (34 that we previously counted plus 2 new ones!). In these 36 nests nests we found 22 chicks that were ready to fledge. This means that by dividing 22 by 36 we get a productivity (breeding success) value of 0.61 chicks successfully raised by each nest. This is a bit lower than last year for this colony (2013 value was 0.74) but is still pretty good.
After checking Little Burhou we then went to Coque Lihou on the 3rd July. We relocated 60 of the 66 nests we had previously counted with the remaining 6 likely to have failed and the nesting material blown away between surveys. However, the 60 nests that we did locate had 43 chicks between them! This means that by dividing 43 by 66 (we have to still count the 6 nests we didn't find again) we get a productivity of 0.65 chicks raised per nest. This is a bit better than Little Burhou and also similar to the Coque Lihou value from 2013 (0.69 productivity). So this colony has had a stable year.