Tracking bands ‘may harm penguins’

Scientists who study penguins may be inadvertently harming them with the metal bands they use to keep track of the birds, according to a new study.

The survival rate of King penguins with metal bands on their flippers was 44 per cent lower than those without bands and banded birds produced far fewer chicks, according to research published in the journal Nature.

The theory is that the metal bands – either aluminium or stainless steel – increase drag on the penguins when they swim, making them work harder, the authors of the study said. Consequently, studies that use banded penguins – including ones about the effects of global warming on the seabirds – may be inaccurate, mixing up other changes in penguin life with the effects from banding, said author Yvon Le Maho of the University of Strasbourg.

Dr Le Maho said there was now an “ethical question” surrounding the practice of banding penguins.

The researchers followed 50 already banded adult penguins and 50 without bands for 10 years, tracking them with under-the-skin transponders.

Among the non-banded seabirds, 36 per cent survived for ten years, compared with only 20 per cent of those which wore bands.

Penguins generally have a life expectancy of around 20 years, while King penguins can live even longer.

The non-banded penguins had 80 chicks, while the banded seabirds produced 47 chicks, a difference of 41 per cent.

Norman Ratcliffe of the British Antarctic Survey, which no longer uses bands, said the study “augments a growing body of evidence” that bands harm the penguins and may bias the studies.

There is an alternative to the metal bands, Ratcliffe and the French researchers said, involving the use of transponder tags that are injected under the penguin’s skin and send radio signals to buried antennas, much like pets with radio chips embedded in them.