On a wing and a prayer | 27 June 2019

In 1979, despite the best efforts of scientists for more than a century, a butterfly called the British Large Blue became extinct. There is widespread concern about the more recent decline in butterfly populations, but the American ecologist Nick Haddad writes that the collective weight of the known populations of the five rarest butterflies he discusses in his sobering book is just ‘three pounds five ounces — as much as one panda’s paw’.