As evening approaches, quietly grazing mammals hop cautiously out into the meadows of Rathlin, their long ears, twitchy noses and large hind feet identifying them as leporids – members of the rabbit family, Leporidae. The island has both European Rabbits and Irish Hares and, although neither is truly native to Rathlin, this is a good place to compare the two species side by side. Not only that, but the island is home to the mysterious and beautiful ‘Golden Hare’, a rare genetic variant of the Irish Hare that is unique to Rathlin.
Originally native only to Iberia and northwest Africa, European Rabbits were brought to Britain and Ireland by the Romans and they soon proliferated as only rabbits can. They have since been introduced to many other parts of the world where they have generally made a serious pest of themselves with their tunnelling, grazing and phenomenal fecundity.
Rabbits were brought to Rathlin sometime in the second half of the 19th century. Past outbreaks of myxomatosis have kept the population in check, and they are a common prey of the local Buzzards. The introduction of ferrets to Rathlin in the 1980s was intended to control the rabbit numbers but, while these rapacious predators undoubtedly do prey on many rabbits here, they also indiscriminately kill other animals and are disastrous for the island’s native wildlife, particularly burrowing and ground-nesting species like the Atlantic Puffin, Manx Shearwater and Northern Lapwing.
The Irish Hare is a subspecies of the Mountain Hare, which occurs naturally right across a vast area of northern Europe and Asia. Unlike the Mountain Hares in other countries, the Irish Hares do not turn white in winter and remain largely gingery brown, with just a white tail and underparts, all year.
Irish Hares are much larger and more striking animals than the rabbits, with longer ears and longer hind legs giving them a lankier appearance. They also have a richer gingery coat and black tips to their ears. Hares can look beautifully elegant and stately, but they often come across as amusingly gangly and dorky when they burst startled from the undergrowth. Unlike Rabbits, Hares don’t make burrows, living instead in a small depression in the ground, usually hidden in vegetation. The proper name for this depression is a ‘form’, but we like to call it the hare’s lair.
According to Philip Watson’s book Rathlin Nature and Folklore (a fascinating and highly readable introduction to the island’s natural history), Irish Hares were first brought to the Rathlin for sport by about 1784, much earlier than the rabbits. A second introduction in the 1950s replenished the population which had by that time been wiped out by shooting for sport and for the pot. Currently, little shooting occurs on the island and the hares seem to be thriving here.
Rathlin Nature and Folklore also mentions old tales of Rathlin hares sucking the milk of cows. We have not yet observed this behaviour ourselves, but we’ll certainly be keeping an eye out for that!
Among Rathlin’s population of Irish Hares, a small minority of animals have a very striking appearance. They have stunningly pale blonde fur all over and, when seen up close, bright blue eyes. ‘Normal’ Irish Hares can be quite variable in fur colour, but a true ‘Golden Hare’ is unmistakeable. To see one is a special thrill indeed. These highly distinctive Golden Hares only occur on Rathlin Island, and it’s most likely their insular separation that has given rise to this unique population.
When mammal populations become isolated on small islands, the low number of individuals creates a genetic ‘bottleneck’, which can result in reduced genetic diversity or distorted gene frequencies. Genes that were common in the original mainland population could happen to be rare or absent in the small sample of animals released on the island, while mutations that were rare in the wider population can find themselves disproportionately common within the small new community. This may explain how characteristics that are generally very rare, such as pigment deficiency (leucism), can be more prevalent among small and isolated populations. It’s likely that Rathlin’s Golden Hare arose in this way, perhaps facilitated by the relative lack of predators here.
There are multiple other cases of mammals on small islands having unusual colour forms. Check out the white wallabies on Bruny Island off Tasmania, or Alderney’s blonde hedgehogs. Or, at the other end of the pigmentation spectrum, there are large numbers of black European Rabbits on several Scottish Islands.
The first sighting of a Golden Hare was around the early 1970s, when islander Liam McFaul recalls noticing an unusual pale hare and, after creeping close enough, being surprised to see that it had blue eyes. He also recounts that, soon after this first encounter, the unfortunate animal was shot by a neighbour for dinner. Despite the demise of this individual, its blonde genes must already have become established among Rathlin’s Irish Hare population because the blue-eyed blondes popped up again in later generations and have been a noted feature of the island ever since.
We are greatly intrigued by Rathlin’s Golden Hares. Can they be male and female, or are they always of one gender? Do Golden Hares produce golden leverets? Several very close encounters with our local Golden Hare left us wondering if they have impaired vision, particularly as poor eyesight can be associated with pigment deficiencies. Are they otherwise weaker, more susceptible to disease, more likely to be caught by predators than the normal hares? Unfortunately, we have been unable to find any published studies of the Golden Hare, so we have no answers to these questions so far.
A visitor to the island who manages to see a genuine Golden Hare has been very lucky indeed, as there are never more than a handful of them in existence. In 2017 we knew of at least four, and perhaps five, different golden individuals on the island, but in some years it seems there are no more than one or two.
We were intrigued to see this lovely leporid lolloping around in 2017. It’s an Irish Hare, but it’s very different to all the other hares on the island. In fact, it looks very like a (non-Irish) Mountain Hare wearing its mostly white winter coat. Jokingly, we call it the Silver Hare. Presumably it is a mutant, another genetic anomaly of the sort that crops up so easily in isolated mammal populations.
We expect the Silver Hare is a one-off but, who knows? Perhaps it will breed successfully and give rise to a whole lineage of similar-looking Silver Hares, living here alongside its Golden cousins and all the other more traditional bronze-coloured ones – a full podium of Rathlin hares.