Dear Readers, Lundy is a small island off the coast of North Devon, and this year it has been the scene of a remarkable rebound in the number of seabirds that nest on its cliffs. 25,000 Manx shearwaters, 95% of England’s population of the species, nested here this summer, along with 1,335 puffins and 150 pairs of storm petrels, who have only been using the island since 2014. This is in spite of the threat of avian flu, which has severely damaged seabird populations in other parts of the UK, and in spite of the problem of a dramatic decline in the number of sand eels that provide food for the birds.
In 2000, just over 7000 Manx shearwaters were counted, and only 13 puffins were seen in 2001. In the 1930s it was estimated that the island was home to more than 80,000 seabirds. So what caused the decline?
Now, I love a rat as much as the next person, but there’s no doubt that they can wreak havoc when they find a population of ground-nesting or cliff-nesting birds. The eggs are easy to steal, and the chicks are unprotected when the parents are out fishing. In some places, rats and mice are eating albatross chicks alive as they sit helpless in their nests.
Both black and brown rats came in the supply boats that visited Lundy over many decades, and liked the location so much that they stayed and bred. But from 2002-2004, a coalition of the RSPB, Natural England, the Landmark Trust and the National Trust worked together to completely eradicate rats from the island. They succeeded, and there is an ongoing monitoring programme because clearly the boats that still arrive with visitors and wardens could have furry stowaways.
Animal rights campaigners were very angry at the destruction of the rats, arguing that the organisations involved were valuing tourist-friendly birds over the rodents. From a purely ethical point of view, I can see where they were coming from – both birds and rats are intelligent, sentient beings, so why would the life of a bird be worth more than the life of a rat? But sadly, human beings travel from place to place, messing things up, taking their rats and cats and rabbits and Dutch elm disease and ash dieback with them, and it’s the local ecosystem that bears the cost. This was, in effect, an attempt to turn back time, to a time before the rats reached critical mass and began to destroy the bird population. With better biocontrol hopefully such a thing will never need to be done again. We are only just waking up to the disastrous effect that alien organisms can have when they find themselves with no natural predators and a conducive environment. Let’s hope that we can nip more problems in the bud, rather than letting them get to the stage where we need to kill thousands of animals in order to protect other animals.