For the past few years, the RSPB Orkney team have been observing signs of gannets prospecting the Marwick cliffs as a new breeding site.  Sub-adult birds loafing nearby, the occasional sky-pointing display, and a few birds seen carrying seaweed to the cliffs have all been promising signs of potential breeding activity!

(Sky-pointing is a displaying behaviour which gannets employ to attract a mate, raising their heads to the sky and clacking their long beaks together.  As with puffins and other seabird species, gannets mate for life, and they continue to engage in this behaviour throughout their lives, apparently as a way to reinforce their bonds)

gannets sky-pointing, Ben Andrew, RSPB Images

Gannets sky-pointing, Ben Andrew, RSPB Images

Finally, this year adult birds - perhaps those same sub-adults from previous years - have returned in earnest, and from early on in the season it was apparent that there were around 30-40 adult and sub-adult birds present around the cliffs.

We first got confirmation of an apparently occupied nest from local naturalist Martin Gray, who managed to visit the site in mid-June and photographed what appeared to be an incubating adult bird on a nest. There may be other nests present nearby but out of sight, as parts of birds can be observed sticking out around the corner of the cliff also.

Location of new gannet colony on Marwick cliffs and apparent nest, photos by James Butcher

Gannets on ledge at new colony site at Marwick, photos by Gerry Cannon

Gannets are already well established at another of our Orkney reserves, Noup Cliffs on Westray.  It was as recently as 2003 when just 5 nests were discovered here and a single chick fledged.  Roll on 13 years to 2016 and there were a minimum of 1020 apparently occupied nests noted during a count carried out by RSPB staff stationed along the cliffs at Noup Head.  The most recent population count, in 2019, found 1592 apparently occupied nests, so the steep population increase continues, and may explain the current colonisation of Marwick.  If the Marwick birds follow the pattern of colonisation seen at Noup, it’s possible that within 10 years we could have 100 – 500 pairs on the cliffs at Marwick – watch this space!

The Northern Gannet is otherwise known as a Solan Goose in the UK.  It’s scientific name is Morus bassanus, the genus name from the Greek Morus meaning ‘foolish’, and species name bassanus from Bass Rock in the Firth of Forth, which remains the largest gannet colony in the world.  The ‘foolish’ is believed to refer to the observed lack of fear of the birds, which made them easy to catch in the days when they were used as a food source.

Gannets at Bass Rock colony, Andy Hay, RSPB images

The UK is home to around 300,000 nesting pairs, which makes up two-thirds of the entire global population of northern gannets, with the majority of colonies being in Scotland.  Gannets usually nest on islands with steep rocky coasts or out on remote sea cliffs in the North Atlantic area, and more rarely on mainland cliffs. Outside of the breeding season, they live out on the open ocean.  Nesting in colonies, they begin breeding when they reach the age of 4 to 5 years, and will return to the same site in their pairs year after year. Once colonies become full, and there is no more room on the rock ledges for any more nests to be made, the next generation of birds will begin to look for new colony sites – likely to be the reason for the establishment of the new colony at Marwick.

The large nests are made by the male partners, using a variety of foraged materials including seaweed.  Sadly, discarded plastic waste can be mistaken for seaweed by the birds, and this can strangle or choke them. Usually only a single egg is laid, and incubated for over 40 days, with both parents aggressively defending the nest. The chicks remain in the nest for a relatively long time, not leaving until the end of August or into September. They are at first fed regurgitated fish by their parents, then whole fish as they grow. The chicks are dark grey-brown coloured when they leave the nest, gradually attaining their adult plumage over their first 3 to 4 years of life.  Their plumage shows different degrees of speckling and dark colouration until their 4th winter when they will have the distinctive bright white adult plumage with golden head and black wing-tips, along with their striking light blue eyes.

Immature gannet in flight, Andy Hay, RSPB images

Gannets are instantly recognisable due to their large size and colouring, their long narrow wings and of course their stunning dives. They dive for fish from heights of between 10 and 40 metres and can reach speeds of 100km/h when they plunge into the water – they have evolved strong neck muscles, protective membranes over their eyes, and a network of air sacs between under their skin to cushion the impact of hitting the surface of the sea at high speed. Their feathers are waterproof, allowing them to spend long periods of time in the water.  Once a gannet has plunged into a shoal and caught it’s prey, often herring or mackerel, it will usually eat the fish underwater before resurfacing.

  

Gannet diving, photo by Nicki Gwynn-Jones FRPS 

Gannets typically live until around the age of 15 – 20 years old, although the oldest known ringed Gannet was found at the age of a whopping 37 years and 4 months old! They are fascinating and truly beautiful birds, and we are really looking forward to being able to watch them at Marwick for many years to come.

Gannet over water, photo by Nicki Gwynn-Jones, FRPS 

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