Birds by Dr Bryan Nelson

It is fewer than 50 years since I became enmeshed in the Bass Rock gannets and in that short span the changes on the Rock have been as monumental as those which occurred in the previous century and even in the 300 years before that. In a way, these three periods (50, 100 and 450 years ago) encapsulate much of the history of this plug of basalt, mate to its mainland companion, the North Berwick Law and a chain of others across the Lothian plain. The 16th century found the Bass, already an ancient stronghold fortified with cannon, intensively cultivated in parts, its gannets carefully exploited for food ("amongst our viands I must not forget the sole and goose, a most delicate fowl"), feathers (almost 300 gannets were needed to stuff one feather bed!) and fat ("they make an excellent oyle called the gibanistick which is exceedingly good for healing anie sore"). By then, this austere crag had already entranced naturalists, kings and historians. By 1850 the Rock, already 150 years in the possession of the Dalrymples who still own it, had long been de-fortified (1701) and the centuries of exploitation of gannets were drawing to a close. Demand for 'gugas' had declined well before the Wild Birds Protection Act. Then came the building of the lighthouse in 1903 and nearly a century's custodianship by Her Majesty's Commissioners of Northern Lights. Order reigned and the Rock was spick and span. The gannets knew their place and this was largely on the cliffs. In the heyday of the Bass as a famous light, when the keepers cooked on a coal-fired range, kept food in a limed hanging larder and lead-lined storage bins, bathed in a galvanised tub and read by paraffin lamps, my wife and I had the rare privilege of living for three years in the ruined chapel half way up the Bass. Shortly afterwards - I almost write "all hell broke loose" but what I should say is - the Rock entered the modern age, which may amount to the same thing. Television, refrigeration, formica and plastic, relief by helicopter and finally, automation of the light, arrived. When the keepers left in 1988 and as the gannets continued to increase, the Rock soon reverted to a more natural state, a process which continues. Indeed the old Rock is rapidly being denuded of its turf and topsoil as the gannets spread and this is cascading down the slope and piling up on the path and in the courtyard.

The Bass has long shared with one or two other gannetries, notably St.Kilda and the Canadian Great Bird of Bird Rocks in the Magdalen Islands (at one time the largest of all gannetries), the distinction of being the most famous in the world. It was the first to be mentioned in literature (perhaps 6th Century) and now could well be the largest single-rock gannetry. Grassholm may be pushing a bit, but Ailsa lies well astern. In my short time the Bass population has increased from 6-8,000 apparently occupied sites (which is nearly the same thing as pairs) in 1962, to 13,500 (1977), 21,600 (1985) and 30-40,000 (1994) which is the last count. This most recent estimate (already well out of date) has the inevitably large margin of possible error. The lower of the two figures excluded the large number of pre-breeders, most of which should not be included in the category of 'apparently occupied sites'' though it is difficult to disentangle them. Largely due to them, the count can vary by thousands within a few days. The dramatic spread has taken breeding birds from the top of the northwest cliffs to the very summit of the Rock. Spreading from the east side they have blanketed the ground and would long ago have covered the concrete path and continued upwards to meet their fellows from the northwest but for the human traffic. Gannets are also proceeding apace down the crags towards the chapel to join up with the group directly behind the lighthouse. This latter numbered 10 pairs in 1961 and is now well over 1,000 strong and beseiging the entrance to the chapel. They confront the visitor a mere foot from the edge of the path. The east flats above the lighthouse, had not a single gannet in the early 60s and are now blanketed. Most of the gulley headland, not long ago covered by turf and the Dalrymples' favourite picnic spot, has now been taken over, though many of them are still pre-breeders. Even the low rocks by the inner landing, for long the preserve of guillemots and shags, is rapidly being colonised. The south slope below the battlements is still free but old records say it once held over 300 pairs and no doubt it will do so again. From North Berwick and Tantallon, the Rock appears to be well nigh covered, apart from a wide and variable strip roughly bordering the path. Most of the gannets between the top of the path and the summit cairn are not yet breeding. Many are 2 or 3 years old which come and go. Others are pre-breeders establishing a definitive site in the season before breeding for the first time.

This steady increase has been largely fuelled by the output of the Bass itself rather than by the large scale immigration which has characterised some other gannetries at certain stages of their growth. In turn, output has rested on consistently high breeding success, itself predicated on the reliable source of food which the gannet's far-foraging, deep-diving and wide prey-spectrum ensures. Bass gannets have been remarkably free from the lean years suffered by some other Bass Rock seabirds, such as kittiwake and shag.

In addition to gannets, the Bass is home to guillemots, razorbills, puffins, fulmars, shags (no cormorants), kittiwakes, herring gulls, lesser black-backs and now a few great black-backs and eiders. The fortunes of almost all these have changed over the years. Herring gulls have declined markedly. They were displaced in hundreds from the north west slopes which are now covered with some 4,000 pairs of gannets. They are increasingly being ousted form the summit area and the south facing escarpment above the chapel. The area in and around the garrison garden has remained a stronghold and it will be interesting to see if the gannets can tolerate this sheltered hollow, which will be difficult for take-off. The garden area is the main stronghold of the lesser black-backed gull. The greaters (3 pairs) are by the garden, near the chapel and near the inner landing. Kittiwakes are markedly down on their previous high. For many years thy have produced fewer young than normal - in some years hardly any. It is difficult to know how the puffins are faring. There have never been many in the battlements, their only present nesting area, and one rarely sees more than 10 or 15 at a time. Gullemots seem to be holding their own in the east caves and have recently increased at the base of the east cliffs. However gannets are encroaching on the inner landing area which was a guillemot stronghold. Razorbills are mainly on the cliffs of cable gulley and around the inner landing but have never been abundant. Shags are hugely down on their previous highs - absent from the base of the east cliffs where once there were scores and many fewer on the inner landing stack. Fulmars have increased slowly over the years but probably still number no more than 50 or 60 pairs, although it is becoming more difficult to view their main area which is the east side of the gulley. One to three eiders breed every year and mallard occasionally.

There are few other species: rock pipit, pied wagtail, starling, hedge sparrow and feral pigeon regularly breed. As on the Isle of May, landfalls of autumn migrants may be massive and often include rarities.

The innovative nature of the Scottish Seabird Centre - and the educational potential of these seabird islands (so near to the Scottish capital, yet still wild and unspoilt), will be harnessed for the good of the seabirds themselves. The more people understand, the more they will care.

Dr Bryan Nelson is a leading seabird biologist and world authority on the behaviour and ecology of gannets. The Scottish Seabird Centre is honoured to have Dr Nelson as a Board Member. As an introduction to the Bass Rock and the seabirds just yards away from the new Scottish Seabird Centre, he has kindly allowed us to use his article recently published in the Journal of the Scottish Ornithologists Club.