How an auction is helping Britain’s turtle doves

“AS SUN to day, as turtle to her mate,” declares Shakespeare’s Troilus of his commitment to Cressida. Chaucer wrote of “the wedded turtledove with her heart true”. Yet Britain has not been kind to these migratory birds, whose numbers in the British Isles have dwindled by 98% since the 1970s to an estimated 3,600 breeding pairs in 2016.

Paul Klemperer, Elizabeth Baldwin and Alex Teytelboym, all of Oxford University, are using economics to help. They have designed a reverse auction in which farmers bid publicly for contracts to provide suitable habitats. This is trickier than it sounds. Turtle doves need wildflower seeds to eat, shallow-sided open water to drink and thick scrubby hedgerows in which to nest—all in proximity. A farmer might wish to provide just one or two of these, and to rely on neighbours to provide the rest. Moreover, breeding pairs must be able to find the sites, but they must not be too clumped together. And finally, the habitats offered by farmers can vary in quality as well as price—a problem Mr Klemperer encountered during the global financial crisis, when designing an auction in which the Bank of England offered emergency loans to banks against collateral of varying quality.

To solve it this time round, the economists constructed an index of turtle-dove happiness (TDH, or “ta-das”). An algorithm...