Five facts you need to know about gannets
Gannets are Scotland’s, and indeed Britain’s, largest seabird. The specific type found here is the northern gannet, identifiable by its bright white plumage, long neck and beak, and distinctive black wing tips.
Northern gannets come to Scotland to nest and breed among huge seabird cities known as ‘colonies’ around the coast. They migrate south for the winter, between August and October, but travel back to our shores at the start of the year in January and February. Since you might be seeing some soon, here are five facts we think you should know about them.
Scotland is responsible for a stunning number of these birds
Our country holds over 40% of the world’s total population of northern gannets, and around 180,000 pairs breed in Scotland. That’s a staggering figure to be responsible for! The gannets are spread out across 14 colonies including Bass Rock in the Firth of Forth, which is the largest gannet colony on earth. You can also find them at St Kilda, Ailsa Craig and RSPB Scotland Troup Head – the latter is the only mainland gannet colony in the country.
Gannets give a whole new meaning to the word ‘speedy’
Gannets feed on a variety of fish at sea, and to catch these fish they have to dive (makes sense). But did you know that when these seabirds actually hit the surface of the water they can be travelling as fast as 60mph?! To do this they have specifically developed neck muscles and a spongy bone plate at the base of their bill to reduce the impact. They also have special membranes to guard their eyes.
The chicks are.....unique
When gannet chicks first hatch they are featherless, as well as being blue or black in colour. They need to be fed a couple of times a day on average by the parents and will keep up this arrangement for about 90 days. When the young do fledge the nest, by around September, they are so chubby and buoyant that they’re not actually capable of surface diving! The fledglings will usually go without food for two or three weeks at this point until they’ve slimmed down a touch and mastered diving. That’s what we mean by unique...
Gannets love to dine and dash
If you’re lucky enough to see gannets feeding out to sea you’ll notice that they do so in large groups, sometimes up to 1,000 birds strong. When they dive, these seabirds swim down to around 15m, staying submerged for only a few seconds. Northern gannets don’t actually take off again with their prize though – they normally quickly swallow their fish before resurfacing, and never fly away with a meal in tow.
Colonies have quite a significant aroma
OK, we’ll be honest with you. You’ll likely smell a gannet colony before you actually see it. With so many seabirds jostling for space on the same cliffs it’s probably not surprising that the scent wafting through the air and right up your nostrils will be powerful. It’s a mix of guano, fish and fresh sea air - on trips out to Bass Rock for example the smell of ammonia can reach you about ten minutes before you get to the colony! However, it’s worth it. The sights, sounds and yes smells of a seabird colony mingle together producing a sensory overload like no other. These seabird cities are one of the great wildlife wonders of the world and we have some fantastic examples right here in Scotland – we’d urge you to get out there and see them.
Charlie McMurray is an intern at RSPB Scotland working on 'all nature' projects: mammals, amphibians and insects - basically everything that isn't birds! Charlie started at the RSPB in January and will be with us for nine months. So far the focus has been natterjack toads and this is an update on that work to this point. Stay tuned, we'll have plenty of updates for you.
Nattering about natterjacks
The New Year brought in a change of scenery for me. In early January, I set up sticks in Edinburgh to start my nine month internship with RSPB Scotland. As an undergraduate zoology student at Manchester, this is my opportunity to see behind the scenes and get stuck into various wildlife projects. So far, about 98% of my time has been taken up by the highly charismatic species, the natterjack toad. And, before the toads emerge after their winter slumbers, I’ve been getting to grips with the story so far...
In 1999, a small amount of natterjack spawn was translocated down the road from Southerness to Mersehead in Dumfries and Galloway. Increasing pressures on the toad’s habitat at Southerness (including an expanding caravan site) meant that the creation of a second population at Mersehead was seen as a sensible insurance policy to safeguard the future of the species in the area. However, in 2014 there was severe local saltwater flooding which raised concerns about the survival of these natterjacks. In response, a three-year survey was launched to see how (and if) they had coped.
So far, the news looks good for these robust amphibians. In 2014, about 45 toads were counted while in 2015, around 180 made themselves known. To get a more accurate estimate of the population size, we embarked on a mission to identify each and every toad at the site, which would help us to see if we were coming across the same individuals more than once.
To do this we needed a reliable way to tell the toads apart. Rather than marking each one invasively by clipping their toes, we decided to use the toad’s natural identifiers: their wart patterns. The beautiful thing about natterjacks is that they each come with their own ID badge in the form of the big warts and the yellow stripe on their backs. Each pattern is completely unique and remains the same throughout its owner's lifetime, just like a human fingerprint. During the 2014 and 2015 seasons, the natterjack team took ‘mugshots’ of as many toads as possible to build up a database.
As that database has grown, it’s become increasingly difficult to identify individual toads by eye alone. It’s taken a whole week to work through our ‘mugshots’ (and there are more to go!).
See if you can have a go yourself...
To ease and quicken the process, we’ve been looking into using recognition programmes, most notably I3S. I3S aids individual recognition of different animals, making it semi-manual rather than fully manual. It’s been used to identify whale flukes, patterns on salamanders and whale sharks, and markings on manta rays. Other studies have shown this to be a really useful aid in surveys like ours, so there was every reason to be hopeful.
Creating the wart pattern database on I3S: the user defines three reference points (tail base and both armpits) and pick out each wart.
A visual representation of an I3S comparison of two wart patterns (red and blue). The green lines show good wart matches. These patterns match (verified by eye) with a low score of 10.62.
The user manually picks out the wart pattern and this is saved within the database. I3S then compares it to the other saved patterns and gives a list of the possible matches or ‘suspects’ along with a score. The lower the score is, the better the match, but each is verified by eye.
Disappointingly, the results from I3S haven’t been as promising as we’d hoped for so far. Between 2014 and 2015, it found only four recaptured individuals, whereas I found nine using eye alone. That leaves the programme’s success rate at only 44% in this situation.
I’m now looking into why man outperformed machine so convincingly. Perhaps there are simple fixes though: we may just need to perfect our photography skills and be really strict about the toad’s posture. How many thoroughly independent and feisty toads do you think will be likely to pose willingly?
I have yet to compare individuals for 2015. Hopefully, a solution will have presented itself before I subject myself to hours of spot-the-difference accompanied by countless podcasts. If not, I guess I’ll be feeling warty-eyed for the next few months.
Despite the bumps in the road for quick and easy identification, there is every reason to be optimistic about how the toads are faring. The recapture rate is low, suggesting that the population might be bigger than we’d predicted and proving that natterjacks really are made of tough stuff.
Hopefully, they’re snug in their burrows at the moment, pondering over how to give us some more fantastic data this year. Let’s keep our fingers crossed for a strong season – we’ll keep you up to date!
The second installment of the Crook of Baldoon story from RSPB Scotland's Jenny Tweedie. RSPB Scotland purchased a piece of land known as Crook of Baldoon six years ago and this is how we've been transforming it into a haven for wildlife ever since. Our work here could not have been achieved without the generous help of HSBC, the National Lottery through the Heritage Lottery Fund, Dumfries and Galloway Leader, Scottish Natural Heritage, and of course, the support of RSPB members.
Crook of Baldoon: Part II
Can’t see the crook for the trees
Removing the willow from the Crook of Baldoon was always a high priority, but we wanted to harvest it as a crop, and do it in the most cost-effective way possible. And that took time.
Due to various delays with both the contractors and the weather, and having to wait for a time when we’d cause the least disturbance to wildlife, if was autumn 2014 before we could get heavy machinery on site to do the work. Willow isn’t an easy crop to cut, and you need quite specialist kit, which is in limited supply in the UK. But eventually it was all removed, chipped, and the harvest taken to a biomass plant in Cumbria owned by Iggesund, who had organised the harvesting for us.
Even once the main crop was gone, there was still the issue of what to do with the remaining stumps. Willow is notorious for re-sprouting, indeed that’s why it’s grown as a coppicing crop, and has been for hundreds of years. If we’d left it as it was, it would have come back, so the ground had to be mulched, and then sprayed to kill off the remaining growth.
But by July of last year, new contractors were able to get onto the site with massive earth moving kit, and they started work on a large lagoon and other wetland features, following a bespoke design that was put together by our colleagues in Scotland and at our UK headquarters.
The idea was to create tailor-made areas for birds that were breeding on the site, particularly farmland waders such as lapwings; birds that were passing through on epic migrations; and wintering birds, that choose to spend the colder months in Wigtown Bay, like dunlins, curlews, pink-footed and barnacle geese. The wetland areas were also designed to allow human visitors views of the birds without disturbing them, hopefully encouraging more people to visit the area, and find out just how special this sort of habitat is.
Now, as the winter rains fall, the lagoons and pools have begun to fill up with water. Whooper swans have arrived from Iceland, golden plovers are filling the skies with their displays, and hen harriers can be seen hunting over the wetland. We’ve had hundreds of redwings passing through feeding on hawthorn berries and crab apples, barn owls and short eared owls have both been seen, otters are sometimes spotted and are likely to become more regular visitors, and even little egrets have been recorded using the pools.
At the Crook of Baldoon, in only five short years, the site has been utterly transformed into a home for nature. Wildflowers are blooming once more on the saltmarsh in the spring, frogs are already moving into the new pools, lapwings are still nesting in the summer fields, and thousands upon thousands of migrating birds have been dropping in to spend the winter. We can only wait and see what else is going to pay us a visit as time moves on.
None of this could have been achieved without the support of RSPB members, or our funders, and we’re incredibly grateful for all the support we’ve had through the years. Both Dumfries and Galloway Leader and the National Lottery, through the Heritage Lottery Fund, contributed to our habitat work over our first three years at the Crook, and also part-funded our warden, Paul, along with Scottish Natural Heritage. The final elements of the work at the reserve were funded by HSBC, who kindly donated around £200k over two years.
But the work isn’t over. Next on the list are more facilities for visitors. At the moment, we just have a car park and signage, and Paul runs regular guided walks and other events, including a volunteer work party. This isn’t a reserve where we’re going to build a huge visitor centre, but we do hope to put in some more modest facilities, including viewing areas, hides and toilets.
At the moment, there’s still plenty to see and enjoy, and it’s actually a great time to come and visit. It’s pretty rare to get the opportunity to see a site like this that’s at the beginning of its, hopefully, long life as a nature reserve, and you’re very welcome to come along and experience it as it happens.
For us, it’s incredibly exciting to be at this point, seeing the birds arrive to take advantage of all the hard work, and wondering just what the future is going to bring.
For part I of this blog, click here.