A government proposal to cull half a million owls, in order to save a related species, has raised complicated questions

It sounds like a set-up for an ecological horror film – to save one species of owl, US wildlife officials want to shoot down half a million of its cousins.

The federal government’s latest proposal to save the endangered spotted owls has raised complicated questions about the ethics of killing one species to save another, and the role of humans to intervene in the cascading ecological conundrums that they have caused.

The spotted owl – an elusive icon of the American west – has lost most of its habitat in the old growth forests of the Pacific north-west and Canada due to logging and development. The species has also faced increasing competition from the barred owl – a slightly larger, more successful cousin which was lured west over the last century as settlers and homesteaders reshaped the North American landscape.

Now, to save the spotted owls, the US Fish and Wildlife Service has finalised a proposal to cull hundreds of thousands of barred owls across California, Washington and Oregon over the next 30 years.