We often think that we need to go to very isolated places and remote countries to see wildlife. Most wildlife documentaries paint that picture, and it is a constant with all wild animals. You have to go deep into the wilderness to spot them in their natural environment, virtually untouched by humans. But there are some exceptions, as I found out recently. 

When I took a boat in Hamburg that was headed to the small archipelago of Heligoland in the North Sea, I was expecting an isolated island, battered by wind and waves where birds and wildlife thrive in pure harmony. However, when I set foot on the catamaran that would take me there in three hours, I started to suspect it would not be like that as I spotted several families with kids were coming on board. Not only that, but they were carrying big bags, as if they would stay for quite some time. Indeed, when I got there, I found out that the island was nothing like what I had expected. The main attraction on the island was the long, white sandy beaches that stretch along the shoreline. 

Heligoland is made up of two North Sea islands – the larger Heligoland, and the smaller Düne. While Heligoland is the busier island where the main town is located, with restaurants, shops and hotels, Düne features a few camp grounds and a small airport. Both islands are famous for their sandy beaches that stretch as far as your eyes can see. The magic of these islands goes beyond tourism and long beaches, however, as they show how good management can bring about coexistence between species that are thriving in numbers. On Heligoland, these species are seals and gannets.

The richness of the sea around the Heligoland islands allows seals have an abundance of food and therefore they come in vast numbers. The population keeps increasing year after year and this year’s count on the main island during moulting season resulted in 1,420 individuals. It is not uncommon to find seals around isolated islands, but in Heligoland, they assemble in several colonies. In the north of the main island, they can be seen – and heard – from the distance. During low tide, they rest on the rocks, with their bodies out of the water, singing, shouting and communicating with each other. 

Another species that can be admired here in the North Sea are the gannets of Heligoland. These large seabirds feed on fish and are famous for their distinctive fishing style: flying high above the water surface, they spot schools of fish and then fly from the sky to harpoon the fish, entering the water like javelins. They are known for assembling in nesting colonies and from April to September, they gather to nest and rise their chicks. The biggest colony in Europe is located in the UK, at a site called Bass Rock in Scotland where, during the breeding period, around 150,000 noisy gannets gather.

The colony on Heligoland is Germany’s only colony, and is considerably smaller than the one in Scotland. What it lacks in size, it makes up with special encounters. As the island used to be a military base with a walking path leading around its entirety, the birds don’t know about boundaries. As nesting space is scarce, some gannets decide to nest on the walkways and in close proximity to humans. Incredibly, it has been proven repeatedly, that despite not being in the best possible atmosphere, these gannets that nest here still manage to rise their chicks in defiance of the constant flow of walkers. It is proof that good management strategies and a respectful approach from visitors can help wildlife thrive.

While tourism might not pose a direct threat to these North Sea gannets, my visit revealed an entirely different threat. As Heligoland is surrounded by a very fertile sea, humans have been able to exploit it significantly. Abandoned fishing nets have been left floating in the ocean, and gannets have started to use them as building material for their nests. During my visit, I spot a multitude of colourful nests on the red cliffs on Heligoland. Do the birds mistake these nets for floating macro algae? Do they simply believe it is a good building material? We still don’t know the exact reason why they pick them up, but it is now found in great quantities in the gannet nests. Researchers found that some nests on Heligoland have over 3kg of plastic in them. While it might make for good building material for the seabird nests, it is also the source of many deaths within the colony, as the ends of the ropes and nets, can be a fatal trap for the gannets and other species nesting nearby, if they get entangled.

To assess the effect on the colony, a study on mortality due to entanglement was carried out on the island. Elmar Ballstad, head of the Heligoland Reserve and a member of the Jordsand Association for the Protection of Coastal Birds in Germany, is the driving force behind the project. He says it is vital to be aware of this information in order to help minimise the amount of plastics washed on Heligoland’s coasts. For two years, from 2018 to 2020, the colony was monitored for entanglements of the birds. Although gannets are the species that use the nets for nest construction, other birds are affected as gannets often share nesting space with other birds such as guillemots and kittiwakes. During the two years of the survey, 393 birds were caught in the tangle of ropes and nets of the gannet colony – 216 in the first year and 177 in the second year. These numbers do not include individuals that became entangled but, after struggling, were eventually freed, although several died because of the effort and injuries involved. Of these 393 entangled birds, only 146 were gannets, which means that other species have also been severely affected by the issue.

The gannet colony has been growing exponentially over the last 12 years at an average annual rate of 11.5%, but this does not mean, however, that numbers will continue to grow. Using the monitoring data, previous censuses in the island, and population modelling of other gannet colonies, a prediction of colony growth was made with four different assumptions. In the first assumption, the ‘recruitment’ – the number of breeding birds coming from other colonies each year – was assumed to be zero, and in the other assumptions, 5%, 10% and 15% of recruitment were assumed. In the first case, with no recruitment, the population numbers were very low, and there was a decline of the colony over the years. In the rest of the scenarios, researchers predicted growth, a little lower than the actual colony growth, which led them to believe that the real recruitment of the colony is greater than 15%. 

These results imply that, despite colony growth in three of the four assumptions, the balance is very delicate. It does not take much pressure for the numbers to vary. If birds continue to die from entanglements and plastic pollution, the effects of climate change work against them, and the current avian flu situation increases the pressure, it might cause the number of breeding pairs arriving on the island from other colonies to decline and therefore, lower the recruitment rate. Ultimately, this would result in a quick decline of the population in the island, which could mean that the gannet population might suffer viability problems in the future.

Despite the colony being resilient and having grown steadily over the last few years, these results highlight a problem faced by many other seabird colonies around the world. Based on the results, Elmar and the respective organisations are lobbying the government to further regulate and restrict fishing in the area, and in particular, the use of fishing techniques to minimise the risk of lost or broken nets, which end up in the sea and ultimately in the nests of the gannets.