Thursday, 30 May 2013

Seabird season…

A huge amount of work goes into monitoring the various seabird populations at St Abb’s Head. We monitor the birds mainly by two methods. Firstly by carrying out full colony counts and secondly by studying smaller nest plots for productivity. Annual monitoring has been carried out here for over 35 years, creating a very valuable data set.

Seabirds are a fantastic indicator of the health of the marine environment as they react relatively quickly to changes. By understanding changes in seabird numbers we can get early warning signs of other changes in the marine environment.

Changes in seabird numbers and nest productivity are governed by three main factors; firstly the availability of food, secondly the weather conditions and finally the level of predation at the colony.

Availability of food
If a food supply is poor then generally seabirds suffer a poor breeding season. However seabirds have several clever techniques when food is short; some delay breeding until later in the year when food is more readily available, some refrain from breeding at all and take a year out. Others will travel further to find food and may even change nest site closer to a food supply. Some species will also diversify and switch to more abundant food sources, if they are available. With sea temperatures predicted to continue rising it is likely that we will see continued changes in the amount and types of food available to our seabirds.

It’s important to remember that when food IS readily available then most seabirds will maximise on this with larger, earlier and more successful broods and a greater percentage of chicks will reach fledging stage.


Weather plays a huge role in the life of a seabird, many species such as Auks (Guillemots, Razorbills and Puffins) are well adept to dealing with harsh weather, after all these species spend most of the winter out on the open sea only returning here to breed in the summer. It’s the young birds who suffer most at the mercy of the weather.

Rough seas mean that feeding becomes difficult for adult birds and if poor conditions occur while chicks are still young then they quickly become emaciated and starve from a lack of food. Recently hatched birds also lack the insulating and waterproofing feathers of an adult birds plumage and are thus highly susceptible to exposure, relying on the parent for shelter, warmth and protection.

Over the winter many east coast sites have experienced high numbers of dead birds being washed ashore (known as wrecks). From January to March we received many worrying reports of dead birds (mainly Shags and Auks) being washed up on the beaches here. Most were found in an emaciated condition, perhaps reflecting the difficulty feeding during the prolonged periods of rough weather.

It’s worth noting that many seabirds will usually experience high mortality rates during the winter months, with inexperienced first-year birds often being worst hit. During the first few months of this year the east coast experienced a long period of on-shore wind and this brought any dead birds ashore. These birds will usually decompose at sea so perhaps we are being made more aware this year.

From monitoring it is already clear that 2013 is shaping up to be a poor year for many species. Unfortunately it looks like this year will be an example of how poor weather, particularly during early summer can spell big problems for many species. Only when our full counts and productivity figures have been analysed will be know for sure how species have coped.

Levels of predation
Ever wondered why seabirds choose inaccessible ledges, remote islands and sea stacks as nest sites? The answer is down to the lack of predators at these inaccessible sites. Predators can include animals such as Rat, Fox, Stoat, Weasel as well as other birds. An impressive spectacle at St Abb's Head is when young guillemots begin to jump from the safety of the cliffs to the ocean below. Hungry Herring Gulls lay in wait and pick off ‘jumplings’ not quick enough or accurate enough to make it to safety.

Recently a number of island locations have undertaken rat eradication projects to protect breeding seabirds. Since introduced Brown Rats were eradicated from the Island of Canna the populations of Manx Shearwater have began to return and other seabirds are also benefiting. A huge operation is also currently underway in South Georgia.



With sea temperatures predicted to continue rising and scientists predicting a more erratic weather pattern, it’s thought that the marine environment is likely to undergo some dramatic changes in the not too distant future. With our continued monitoring we will be keeping a careful watch on how our seabirds react to these changes.
With peak seabird breeding season here it’s a great time to experience the sights, sounds and smells of a busy seabird colony. Many birds are now on eggs and others are busy displaying, mating and nest building.

Park at the visitor centre and enjoy a walk around the dramatic coastal scenery of the headland and look out for our rangers carrying out monitoring, we are happy to answer questions but please don’t disturb us mid count... 12,067…12,068… “excuse me, where are the puffins?”... doh’


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