Gannets galore, part 1

One of the highlights for me during the past year was the two visits I made in the summer to the RSPB’s Troup Head Reserve. Situated on the Aberdeenshire coast just east of Banff and about 60 miles from where I live at Findhorn, it is the site of mainland Scotland’s largest colony of gannets. Despite this relative proximity I’d not been there before so when a friend suggested a visit in the middle of July I was very happy to take him up on the invitation.

For me this was one of the unexpected benefits of the Covid lockdown restrictions – like many people I’ve been getting to know Nature in my local area much more, when it’s not been possible to travel further afield. Once I was at Troup Head, of course, I also had to question why, in the more than 40 years I’ve been living on the Moray coast, I’d not made it to this site before!

The cliffs at Troup Head rise up to 90 metres in height, stretching for about 4 km. along the coast, and are home to over 38,000 seabirds during the nesting season. In addition to the gannets, there are large numbers of kittiwakes as well as guillemots, razorbills, puffins, fulmars and several other species. The sheer density of so many birds is very impressive, and it seems as though every available place to perch on the cliffs is occupied.

It’s the gannets that are the star attraction though, and it’s not hard to see why. With a body length of up to a metre, a wingspan of 1.8 metres and plumage that is mainly white, with dark tips to the wings and a buff-coloured head, the northern gannet (to give it its full name) is a large, distinctive and beautifully coloured bird, especially when seen at close proximity, as is possible at Troup Head.

The scientific name for the species is Morus bassanus and it occurs on both coasts of the north Atlantic Ocean, with breeding sites in northeastern North America and Western Europe. The world’s largest breeding colony is on the Bass Rock in the Firth of Forth, further south on the east coast of Scotland – over 75,000 pairs nest there. Gannets only began nesting at Troup Head in 1988 and although the population was estimated at about 6,450 pairs in 2014, the site gives the impression of having many more birds than that.

The cliffs are reached by a short walk from a nearby visitor car park, and in the nesting season the gannets and other birds can be heard before they are seen. The footpath goes quite near to the cliff edge in several places, and the updraft from the sea below means it is usually quite windy there. While this can make walking (or holding a camera steady) a challenge sometimes, the positive side is that gannets can be seen up close in flight at eye level.

Gannets only begin breeding at 4 or 5 years of age, but birds of all ages can be seen on the cliffs. Young individuals have varying amounts of dark feathers in their plumage and this gradually gives way to their adult coloration by the time they are ready to breed. Most of the birds on the cliffs were adults, with the immature ones tending to be on the edges of the colony, and young chicks were visible with their parents at various places as well.

A pair of gannets raise a single chick each year and the birds with chicks seemed to be concentrated together on some of the steepest sections of the cliffs, most likely to reduce the risk of predation. Overall throughout its range, the gannet population appears to be increasing, as evidenced by the recent establishment and growth of this colony at Troup Head, and this is attributed to a high success rate in breeding.

The most recent estimate for the total population of gannets in the world stands at about one million birds. However, it was a different story in the past, mainly due to human pressures such as hunting of the birds for food. The colony on the Bass Rock, for instance, was reduced to 4,000 pairs about 200 years ago, after several centuries of exploitation, but recovered to its present level once hunting was stopped.

Gannets are monogamous and mate for life, with breeding birds returning to their nesting sites in March and April each year. The nest is made from seaweed and plant material, and this is usually collected by the male bird.

A pair of gannets will display considerable affection for each other, greeting one another whenever they reunite at the nest site after one bird has been away feeding at sea etc. This pair bonding behaviour takes several different forms, including preening of the other bird’s neck and clacking their bills together in what is known as ‘mutual fencing’. This is interspersed with calling, bowing and shaking their heads from side to side. These actions help to reinforce the pair bond between the birds, and continue throughout the nesting season.

A female bird lays a single egg that is incubated for about 45 days, during which time it is kept warm by the brooding bird’s distinctively-coloured webbed feet. Those are also used to cover the young chick when it is newly-hatched.

Adult birds feed their young chick initially with partially-digested fish that they regurgitate, but as the chick grows larger it is fed with whole fish. Fledging takes place at about 90 days after a chick has hatched, and the young bird propels itself off the cliff into the air and has to fly straightaway, without having had any opportunity to practice. Once it has left its nest, a chick is unable to return, as its flying skills are not well enough developed for that. Instead it remains out at sea, learning to fish and fly there.

The gannet has an average lifespan of 17 years, and will begin to breed when it is 5 years old. The oldest known individual was recorded in 1998 as being over 37 years old when it died. After breeding is complete, the birds migrate southwards in late August and September each year, before returning to their nesting colony from January onwards – the oldest birds arrive first, followed some weeks later by those of breeding age.

(Continued in part 2)