The flipside of tagging penguins

READERS will be familiar with ‘white -coat hypertension’, a rise in blood pressure triggered by the sight and smell of the doctor’s surgery.

The cull is tightened around the arm and the stethoscope applied but the pressure readings are all over the place. Measurement processes which alter what’s being measured are useless to science. Nor is this just a medical problem; a recent paper in Nature claims that scientists studying penguins have been making a similar error. Information they have been gathering for years is flawed.

Penguins return to their breeding colonies each spring. ‘Roll-calls’ at the sites tell scientists how many birds have made it through the winter and how the species is faring. They study mate fidelity, hatching-success and chick survival rates. But there’s a problem. The birds wear identical uniforms and it’s impossible to tell one individual from another.