‘Recycled rabbits, that’s what you could call them.’ Véronique van Meurs, forester at nature manager PWN, walks with two transport boxes through the North Holland Dune Reserve, just outside Castricum. Together with employees of wildlife shelters in Krommenie and Mijdrecht, she is releasing eight rabbits into the dunes today. Or at least: in the veranda – a circular fence of about seven meters in diameter. The exterior consists of chicken wire and wooden posts; inside is a mound of stumps and sand, topped with branches of sea buckthorn bushes. Stinging nettles, celandine and purple deadnettle grow here and there. “They stay here for two weeks to get used to the outdoors and the environment. Then we release them and they can go out into the wide world on their own.”
Things have been bad for the Dutch dune rabbits for decades. After an outbreak of the deadly disease myxomatosis in 1953, numbers initially seemed to recover, until the viral haemorrhagic syndrome (VHS) emerged in 1990. A second variant of that contagious, fatal virus infection followed in 2015. Today, all three diseases are still circulating in the Netherlands, and in many areas along the coast – traditionally real rabbit strongholds – the populations have still not recovered.
Turned up soil
Counts in the North Holland Dune Reserve show that the rabbits have completely disappeared in many places. Small groups do occur elsewhere, but there is no increase: the birth rates and the death rates are in balance. Van Meurs: “And that while wild rabbits are just so important for the dune landscape. They play a key role, because they spread the calcareous sand with their excavation work. Plant seeds can germinate in that churned up soil, insects are attracted to the flowers, which attract birds – and so on. Sand lizards warm themselves in the sun on the sandy spots and lay their eggs there. Moreover, without the rabbit, the dune violet, the host plant of the rare dune fritillary, would also be lost. Or think of the wheatear, an endangered bird species: it likes to breed in old rabbit holes. And rabbits themselves are natural food for foxes, for example.”
Together with PWN ecologist Myrthe Fonck, Van Meurs became involved about seven years ago in a large-scale project of the knowledge network Development and Management Nature Quality (OBN) about the recovery of the rabbit populations in the coastal dunes. Ecologist Jasja Dekker and colleagues describe in the OBN final report that an average of 0 to 10 rabbits are counted per kilometer of coast (when counting from a car), with local outliers of up to 25 or 40. “We already think 25 is a lot, but that is nothing compared to the numbers we once had, when you almost tripped over the rabbits,” Dekker said on the phone.
You should not suddenly place a rabbit that is used to juicy grass between dune vegetation that is more difficult to digest
Jasja Dekker ecologist
The ecologists also analyzed experiments with the release of rabbits in France, Spain and Portugal, among others, where the rabbit population has also been steadily declining since the second half of the last century. In those cases, it concerned wild rabbits that were chased out of their burrows with the help of ferrets, to be released elsewhere.
With a successful release, about 60 to 70 percent of the rabbits survive in the first two months, says Dekker. “You can see that as a good result. However, it is essential that they reproduce and for this it matters when you release them, and where. You should not suddenly place a rabbit that is used to juicy grass between dune vegetation that is more difficult to digest.”
Buried chicken wire
Predators must also be kept at a distance during the first period. Van Meurs: “For that reason, we have buried the chicken wire at the veranda 60 centimeters deep under the ground, and we provide shelter with sea buckthorn branches. You don’t want a polecat or pine marten to jump in, or a fox to dig underneath.”
Once the rabbits are released after two weeks, they are on their own, although some simple artificial burrows have been made in the sand to accommodate them with an earth auger. “Then they can dig it out themselves.” The area around the verandas has been grazed in advance by sheep, so that the grass is short and rich in protein – just as the new residents like it.
But come on rabbits to release, if the populations are doing so badly in a large part of Europe. Where do you find new pioneers? The report lists a number of small-scale releases: in 2017, for example, 32 rabbits were transported from Maasvlakte 2 to the dunes of Oostvoorne. Rabbits are now also moving to Vlieland from the same location. A win-win situation, because it is precisely in the industrial port area of Maasvlakte 2 that the rabbits are undesirable, and they do it too well. Rabbits are also sometimes caught on golf courses. That catching is still done with the help of ferrets, says Dekker.
We only release rabbits that behave really wild and shy
Nina Schouten Wildlife shelter Krommenie
Van Meurs and Fonck started in 2022, in consultation with Dekker, with a pilot test in the North Holland Dune Reserve: the rabbits they release come from the game shelter. Van Meurs: “At one point I received a phone call from Krommenie: that they had wild rabbits in the shelter, or did I know where they could go? That was the starting signal for our experiment. By deporting them, we give them back a life of freedom.”
There are now three verandas, where thirty rabbits can get used to their life in the dunes and to the local vegetation. Van Meurs: “There have been no rabbits at this location for years. Otherwise, the new residents could disturb the existing group.” The first releases of the past year seemed successful: no dead rabbits have been found so far, and live specimens have been sighted in the area on several occasions. “You immediately saw that their presence attracted all kinds of other life: suddenly we found fox and marten droppings everywhere. More mice and owls also came to the area.” In the game shelter, it often concerns young wild orphan rabbits, whose mother has been bitten to death by a dog or chased away, for example.
Wildcamera’s
Releasing rabbits on your own, emphasizes Nina Schouten of Wildopvang Krommenie, is absolutely not the intention. “Such a tame rabbit, apart from an often deviant appearance that is easily noticed by predators, has no instinct whatsoever. It is waiting to be fed, instead of fleeing in time.” A wild or semi-wild rabbit still has that instinct. “We only release rabbits that have hardly been in contact with people, not even in the game shelter, and behave really wild and shy. Moreover, they also have to look like wild dune rabbits.” However, every rabbit is vaccinated against myxomatosis and VHS. Van Meurs: “That vaccination protects them for a maximum of one year. You then hope that they will also come into contact with the virus in the wild during that time, so that they produce extra antibodies.” Rabbits can also come into contact with their mother’s antibodies in the womb, says Dekker. “Then they already have a stronger start.”
Today, one male rabbit and seven females are released in the veranda. They all get a stripe on their ear, which stays in place for about a month – this is how they can still be recognized during the first weeks in the free field. “Then we know a little bit where they are going. We have also installed four wildlife cameras for the same reason. We plan to also draw blood from future animals so that we can monitor the gene pool and check for antibodies.”
The male, the rattle, is completely wild: he has a distinctive ocher colored spot behind the head, and large eyes. The moment he gets a green mark, he starts to struggle violently. “It is still nice and wild,” concludes Schouten.
Once in the veranda, most of the eight rabbits immediately dart away under the sea buckthorn branches. One female begins to nibble on the purple dead nettle. She is joined by the male, who immediately makes an attempt to pounce on her. Van Meurs, smiling: “Perhaps new dune bunnies will be born in about a month.”
2023-04-27 11:30:54
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