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The Bass Rock

Log: Scottish Seabird Centre

Whether driving the coastal roads or approaching by sea, the Bass Rock is an iconic landmark on the outer edge of the Firth of Forth that is just breath-taking as it gleams in the summer sun.

Stop for a moment and look through binoculars, and you realise that the dazzling white that covers this Rock is not guano but a hub of life, as thousands of gannets (our largest European seabird) have occupied virtually every suitable nesting site.

Nest material (Maggie Sheddan)
Nest material (Maggie Sheddan)

The airspace is alive as they soar overhead; some just swirling in extending columns using the thermals, others with offerings of seaweed or plastic, even netting hanging from their bill for their continuous nest building. Juvenile gannets returning to the Bass for the first time since fledging, fly circuit after circuit around the Rock absorbing their birth colony, never landing, just observing, and sleeping on the seas close-by.

Gannets have been recorded as far back as the 6th century. For many centuries an industry in harvesting guga flourished, bringing valuable income not only as a food source, but feathers and the fat extracted from them was highly valued. In 1592 one of the first laws for conservation was introduced to protect the future of the colony. By Victorian times with the meat falling out of favour, wanton shooting almost decimated this colony.

Thankfully with these times long gone, the colony has grown in strength with Dr Bryan Nelson (who lived on the Rock for four seasons in the 1960s) studying these magnificent seabirds and bringing us the immense understanding of their behaviour that we have today.

Three-hundred-and-forty-million years old, this giant volcanic plug, composed of homogenous trap rock called phonolite or clinkstone, is on the cusp of rich feeding grounds of the North Sea. With sheer cliffs rising 120m out of the sea, this is what makes it the ideal habitat for the North Atlantic gannet (Morus bassanus).

Gannet chick (Maggie Sheddan)
Gannet chick (Maggie Sheddan)

As the weeks pass, the white down on a gannet chick is replaced by the dark speckled plumage of the guga. By 12 to 13 weeks, static on this tiny ledge, its only exercise is to wing flap to strengthen the muscles. Rain stimulates this, creating a wave of dark wing flapping across the Rock (an impressive sight) but as rivers of water can cascade down the rock face after heavy storms, these factors combined can cause substantial mortality to the young on the prime sites.

Until recent times, sheep grazed upon the seven acres, Bass mutton being highly-prized. With the advancement of the gannetry, erosion has taken its toll and today little vegetation remains. Even the shags and gulls are being displaced.

In 2014, an aerial count confirmed that the Bass Rock is now the largest Northern gannet colony in the world with 75,259 AOS (apparently occupied sites), a dramatic increase of 24% since the last count in 2009. But why such a substantial increase when other seabirds in some areas have declined?

Gannets have been recorded foraging several hundred miles from the Bass Rock, although in summer feeding can be closer on the rich tidal banks. Because of their ability to travel such distances, and that they are able to take a variety of prey, they fare better than many other seabird species.

Guga first jump (Maggie Sheddan)
Guga first jump (Maggie Sheddan)

For the moment this is good news but despite current growing population numbers, balance of the food chain is vital. Fishing policies and environmental issues are closely monitored for changes that could have a negative impact on food supplies. This is why research and ongoing studies are vital to monitor these changes.

Leeds and Glasgow Universities are continuing studies this year. One will be deploying geo-locators on breeding birds to establish any changes in the foraging patterns, and what prey species is prevalent in their diet.

With various renewable energy schemes on the horizon, it is important that data is collected to establish possible changes in foraging zones; the potential for any disturbance to their flight paths; or disturbance to the marine habitat that could impact on resources. Winter geo-locators were deployed that brought interesting results showing that female gannets were travelling further during winter, resulting in birds returning in healthier breeding condition than those that did not travel that far. Eggs, too, are gathered every few years to monitor pollutants within.

Aerial shot of Bass Rock (Stuart Murray)
Aerial shot of Bass Rock (Stuart Murray)

Whether I’m landing photographers, naturalists or just on a maintenance trip (scrubbing the landing, often with a young seal watching) my excitement and passion never tires. Many ask ‘when is the best time to land on the Rock?’ To be honest, anytime, but for me, the end of July through to late September when the young are yipping, vying for food, tossing sticks in the air, taking that first jump to their uncertain future.

Adults still display and nest build, the noise is extreme, the odour exceptional and the softer seasonal light is wonderful.

The Bass Rock, just 3 miles from the Scottish Seabird Centre (a mere 35 minute train journey from the city of Edinburgh) truly is a wildlife wonder.

Daily boat trips around the Bass Rock can be booked via the Scottish Seabird Centre

There are also exclusive, specialist, half-day landing trips for photography and wildlife enthusiasts.

www.seabird.org

Maggie Sheddan Senior Bass Rock Guide

Updated information February 2017:

2016 saw the continuing studies from both Leeds and Glasgow Universities. We expect the updates from them in the next few months.

Lothian Ringing group accompanied by a couple of the research team ringed gugas (the fledged young), before they left the Rock in early September. With almost a hundred ‘chicks’ ringed this has been the first time young birds have been ringed for many years now. A report of one being washed ashore in Portugal was met with mixed feelings. It was wonderful to see this fledgling had made it that far south although sadly the thought is it succumbed to violent storms at that time. What was good was to now have a record of one of these fledglings. It shows he value and importance of ringing and although this one didn’t make it how far and where have the other 90 odd reached and will we ever see them return to the Bass?

Updated information March 2020:

In 2018 The beast from the east followed by several weeks of harsh easterly winds impacted on the success of the breeding colony. By April it was clear that many birds were alone and breeders were not yet settled. The few study birds that had returned were found to be significantly underweight. The Leeds researchers concern that this would impact on their ability to successfully breed, was realised.

‘Nest building is not only an important ritual for gannets, affirming the site and the bond between the breeding pair but is vital to keep that chick warm, protecting it from the torrents of water and mud that can pour down the rock and engulf it. The lack of core nest building material such as seaweed was obvious as eggs were laid on bare ground, with no protection. July saw seaweed being carried in but it was a poor breeding season with many birds taking a year out.

2019 proved a more settled year although egg laying dates and fledging are later than used to be the norm

Climatic changes, strong winds, stormy seas, torrential rain, what will 2020 bring for our seabirds?

Updated information November 2020:

March 2020 The new season was on the cusp, pairs reunited after months apart, displaying, renovating nests after winter storms. Leeds researchers planed a visit late April to retrieve winter loggers

The world changed! Reserves and islands closed. Travel restricted.

Seabird counts, ringing and tagging, the loss of data and continuity in recording over these months has been impossible to fulfil.

Gannets have a long season. Breeding was in full swing when we finally landed mid-July and looked very productive. It was wonderful to see ‘flighty ‘fringe birds sitting on eggs and successfully fledge their young. A few resident Herring gulls continue to predate on eggs but the gannets are slowly pushing them out of their breeding areas. Hopefully for 2021 studies and counts can resume for all reserves. It will be interesting to see if there are any significant changes where wildlife have moved in during this period of human constraint.

Updated information October 2021:

Late March reunited pairs were settling. The colony was looking good, when snow and gales engulfed for several days. The Rock emptied. It was 10 days before the birds returned to resume the bonding and nest building. The first egg was spotted in June (later than normal) Had the heavy rain in May washed nests away? These climatic bursts can impact greatly on wildlife. Despite this it has been a good season. Landing late October over 200 gugas were seen along with a handful of young chicks, the youngest 6wks. Will the parents continue to nurture it? We have witnessed this before but the chick was abandoned late November when the winter storms kicked in.

Leeds University paper has been published Movements, migration and mortality of juvenile gannets Dr Jude Lane has written a blog on the Juvenile Gannet Research which can be found on the Scottish Seabird Centre website An interesting insight to these first few weeks after fledging.

Updated information October 2022:

2022 A positive start. No weather issues, no covid

Mid May: Reports of Avian Influenza in seabirds was worrying.
HPAI was confirmed on the Bass early June. The speed and cruelty of this virus was truly heart-breaking. Research stopped. With strict biosecurity and full PPE, we could only observe, try to understand and learn. Gulls predated abandoned eggs. They survived but not their young. The rock fell silent, the colony decimated. There were small pockets of hope where a few survived and reared healthy young.
It was interesting to see a change in behaviour with a species notorious for territorial dispute. Adults mingled, young wandered without threat.

Early July had it run its course? Immature birds began to appear, seldom seen in recent years. There had been no space. Where had these birds come from? Where were they going? So many questions.

Black/ flecked eyes we thought a sign of infection? Most died but a handful survived and bred. Did this show immunity?
Late season exemptions were granted. Under strict biosecurity samples were taken and tags deployed on a few birds We wait.

The Bass will survive. The dynamics will change but 2023 will be interesting and exciting.

Updated information October 2023:

There was a nervous anticipation as the season approached. On March 27th seen on the SSC webcams returning birds began to settle on their territories awaiting the return of their partner but, how many birds had lost a partner? How many pairs died? We knew the colony would be very different. Many established pairs reunited in April. The joy to see nest building, affection, and aggression! It began to sound like the gannetry we knew.

By May it was patently obvious there were many single birds along with swathing gaps across the colony that had previously been densely populated. For the first time in years’ immatures wandered among breeders, as did the predatory gulls. It’s been heart-warming to see a very successful breeding season. It’s exciting to understand and observe the changes, and how the colony will regenerate.

The black / marbled eye we thought diagnostic of HPAI and probable death, research has shown many birds have survived the virus and have antibodies. It is very odd to see a bird with one black eye and one steely blue. Exciting research ongoing. More can be found on the Seabird Centres’ web site about all the ongoing research


First published in CJS Focus on Marine & Coastal Environments in association with the Marine Conservation Society (MCS) on 25 May 2015


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Posted On: 25/05/2015

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