is your pet cat bad for wildlife?

Whilst the full extent of population level impacts are currently unknown, the number of wild animals estimated to be killed by domestic cats annually is definitely cause for concern. In the US, Dauphiné and Cooper (2009) predicted over 1 billion birds were killed every year, whilst Loss et al. (2013) estimated between 1.4–3.7 billion birds and 6.9–20.7 billion mammals. In Canada, numbers have been estimated at around 100–350 million birds per year and in the UK it is thought between 85-100 million wild animals are killed annually. And these are just the lethal effects. Sub-lethal effects have been detected too, and whilst these are much less studied, a study looking at blackbirds found significantly lower chick provisioning rates when exposed to a domesticated cat, compared to squirrel or rabbit (Bonnington et al. 2013). 

But the trouble is, cat owners don't appear to be aware of the ecological impact of their cats (Mcdonald et al. 2015). It is hard to convey that it is the sheer number of cats, each contributing to the total, that is causing such huge damage to our native wildlife. But what can we do about this threat? Domestic cats are so intrinsically linked to humans that typical methods of invasive species control are just not viable. Cat owners are primarily concerned about the welfare of their pet, making the whole topic of cat management quite a controversial area. Laws are fairly strict in Australia, where cats have been responsible for the demise of native species. Each cat must be registered with the council, sterilized and chipped.

But what about the UK where there isn't currently policy enforcing certain management actions? What can cat owners do to help?

- Cats wearing anti-predator bibs caught significantly fewer prey compared to cats with no bib (Calver et al. 2007) suggesting this rather fetching accessory could be one option (though it could make the cat more obvious leading to more sub-lethal effects)

Credit: Sue Mandeville / Cat Goods, Inc.

- Bell fitted collars have been shown to reduce prey catches by around 50% (Ruxton et al. 2002)

- Curfews (ie. limiting time spent outside) can be effective in reducing prey catches (Woods et al 2002, Mcdonald et al. 2015)

- Neutering your cat to reduce population growth (which was found to be the most widely accepted option by respondents in the UK - Mcdonald et al. 2015).

- Declawing to reduce catch rate (though this wasn't very popular in an Australian survey (Thomas et al. 2012).

So there are ways that cat owners can help limit the impact of their cat, and it's important for owners to remember that it is the cumulative impact of around 9 million cats across the UK that is doing the damage. Simple actions like ensuring your cat is wearing a bell, or locking it in at night could really go a long way to reducing the threat to our native wildlife.