The headline is somewhat startling. Australians, reading this article, would be horrified because the authorities in Australia are super-sensitive to feral cat predation of native species. And the reason why feral cats are on the island of Australia is because of human carelessness in the first-place hundreds of years ago.
And here, today, we have a similar scenario evolving with allegedly feral cats running amok on the island of Barra in the Outer Hebrides of Scotland presenting a dire risk to small ground-dwelling mammals and birds on that island.
Barra is an area of about 23 mi² being 11 miles long and 6 miles wide. It’s a small island. Rapidly procreating feral cats could do some damage to ground-dwelling mammals and birds.
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Source of the problem
The reason why these feral cats exist is because a couple, we are told, had more than 20 cats living in a barn. The couple died and it appears that the cats were not sterilised. They have procreated and they continue to do so.
Plans to tackle the problem
Volunteers involved in the rescue of these cats estimate that there now might be forty and they appear to have exited the barn and gone out into the wilds of Barra to survive.
The kitten season begins in April which makes matters more concerning according to Western Isles Support for Cats and Kittens.
Volunteers from the charity have launched plans to rescue the cats in the weeks ahead. The human population of the island is 1,000 but they don’t have a veterinary clinic, which might create a small complication in sterilising the cats after they been trapped.
The plan is to trap the cats and taken to the nearby island of Lewis to be neutered and then find homes throughout Scotland’s Western Isles. On that basis, I’ve made the presumption that the cats are not true feral cats but semi-feral and are adoptable.
The volunteers think that the cats might be driven to preying on the wild bird population because there’s not a lot of ground dwelling mammals such as rodents and rabbits.
Mammals of Barra
My research indicates that the pygmy shrew is present on the island. There are bats and rats. Cats do prey on bats. Other terrestrial mammals in the Outer Hebrides, including I presume on Barra, are the American mink and the hedgehog. Hedgehogs were introduced to the island to kill slugs but they now are a problem themselves which is not untypical of misplaced ideas of conservation.
Birds of Barra
Three hundred and twenty-seven species of birds have been recorded in the Western Isles of Scotland. On the island of Barra there are many species of bird including the following:
- Corncrake (Crex crex): Barra is known for its population of corncrakes, which are elusive ground-nesting birds with a distinctive rasping call.
- Golden Eagle (Aquila chrysaetos): These majestic birds of prey can be spotted soaring above the island’s rugged landscapes.
- Red-throated Diver (Gavia stellata): Barra’s lochs provide an excellent habitat for these diving birds, known for their haunting calls.
- Arctic Tern (Sterna paradisaea): These small migratory seabirds can be seen around Barra’s coastal areas during the breeding season.
- Twite (Linaria flavirostris): Twite, a small finch species, can be found in the island’s coastal grasslands and machair habitats.
- Oystercatcher (Haematopus ostralegus): These distinctive black and white wading birds with long orange bills are common along Barra’s shores.
- Hen Harrier (Circus cyaneus): Barra’s moorlands provide an excellent habitat for these raptors, known for their graceful flight.
- Great Northern Diver (Gavia immer): Also known as the common loon, these large diving birds can be spotted in Barra’s coastal waters.
- Rock Pipit (Anthus petrosus): This small brownish bird can be seen hopping and foraging on Barra’s rocky shorelines.
- Common Eider (Somateria mollissima): These sea ducks are often seen around Barra’s coastal waters, where they nest and feed.
Bird populations can vary throughout the year due to migration patterns and breeding seasons. The story is an example of how unsterilised, escaped domestic or semi-feral cats on small islands can harm wildlife.
Cat predation on birds on islands
My AI assistant tells me this about cat predation on birds on islands:
There are documented cases where introduced cats have had a significant impact on bird populations, including potentially leading to the extinction of certain bird species on islands. Here are a few examples:
- Stephens Island Wren (Traversia lyalli) – Around the late 19th century, a lighthouse keeper’s cat named Tibbles was brought to Stephens Island in New Zealand. Tibbles preyed upon the local flightless Stephens Island Wrens, which were already critically endangered due to habitat destruction from grazing goats. The combination of habitat degradation and predation by cats led to the rapid extinction of the Stephens Island Wren, with Tibbles being blamed for their demise.
- Guadalupe Storm-petrel (Oceanodroma macrodactyla) – On Guadalupe Island off the coast of Baja California, Mexico, introduced feral cats have been a major threat to the native seabirds, including the Guadalupe Storm-petrel. These cats have preyed upon the storm-petrels and their nests, leading to a significant decline in their population. The Guadalupe Storm-petrel is now considered critically endangered, largely due to predation by cats.
- Lord Howe Island Stick Insect (Dryococelus australis) – Although not a bird, the case of the Lord Howe Island Stick Insect is worth mentioning. This large, flightless insect was once abundant on Lord Howe Island, Australia. However, the introduction of black rats, which were predated upon by feral cats, led to the extinction of the stick insect in the 1920s. Fortunately, a small population of these insects was rediscovered on a nearby island, and conservation efforts are now underway to protect and breed them in captivity
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