Auchnerran is blessed with an abundance of many different types of wildlife, from bumblebees and earthworms, to curlew and red squirrel. However, it is also cursed with an over-abundance of rabbits. When we first took over the management of the farm, a pest-control company estimated the population at around 20,000 animals. Our monitoring since then, though not perfect, has estimated the density of rabbits using the grass fields at different times of the year at up to 24/ha, and we know that in areas close to rabbit warrens (which cover approx. 11% of the farms surface area) they are eating significant volumes of grass, reducing that available to the sheep.
Rabbit warrens (red areas) at GWSDF in April 2018.
Rabbit warrens (red areas) at GWSDF in April 2018.
Their abundance is probably important in other ways too. There can be no question that they will provide ample food for the many predators in the area – especially raptors, so could have an important place in the food chain, raising the interesting question of what will happen if their numbers fall significantly. In July 2018 efforts to remove a large proportion of the rabbit population began. Approximately 7,000 were removed over the summer mainly by shooting at night using night vision kit, as well as shooting during the day using both rifles and shot guns. Licensed fumigation methods have also been used.
Throughout this process our basic monitoring will continue, so that we can assess the success of the control efforts and their possible impact on other species. It is important to emphasise that this is not an attempt to eliminate rabbits (even if that were possible) but to reduce their numbers and therefore the degree of damage they cause.
This is particularly timely as some researchers have suggested that, although rabbit populations are at a relative low point across the UK at present because of the impact of new diseases such as rabbit haemorrhagic disease, there is some evidence that they may be developing resistance and on the increase again. If we do not get on top of the GWSDF population now, we may never manage it!
