Published online 12 January 2011 | Nature | doi:10.1038/news.2011.15


Band of bothers

Researchers' flipper bands can seriously dent penguin survival, and also skew the results of research.

banded penguinsFlipper banding has been found to hurt penguins.Benoît Gineste

Attaching bands to penguins' flippers makes them easier for scientists to study, but may also up the birds' death rates and lower their chances of reproducing.

A team studying king penguins (Aptenodytes patagonicus) has rekindled this debate, which has been running for more than 30 years, and thrown up an additional concern. Not only do bands placed around the birds' flippers make life more difficult for penguins, their effects also undermine the conclusions drawn from such studies1.

Biologists have long feared that the tags, bands and transmitters they attach to animals could have a negative effect on their study subjects. The debate has been especially fraught where penguins are concerned because some studies have found problems with bands whereas others have found none.

Yvon Le Maho at the University of Strasbourg in France, an author of the current study, published in Nature, says that the time has come for ecologists to embrace new technologies and abandon flipper bands, "certainly as a precautionary principle".

His group's paper also highlights a wider issue: studies on penguins can and are being used to look at the effects of climate change on ecosystems. Le Maho and colleagues have previously used electronic tagging of king penguins to show that just 0.26 ºC of warming in sea-surface temperatures could trigger a 9% decline in adult survival2. If banding were used in such studies, its consequences on a population could cripple attempts to extrapolate a climate-linked trend from the data.

"It's very difficult to anticipate what the consequences are," Le Maho says. He says there is a problem with warming affecting ecosystems, but "the numbers have to be reconsidered" where they have been derived from banded studies.

Flippin' heck!

As long ago as the 1970s, zookeepers noticed that bands could cause wounds on penguins, especially when the birds were moulting. Later work by biologists such as Rory Wilson of Swansea University, UK — who pens a News & Views on the latest findings in this week's Nature3 — found that bands could also disrupt the birds' hydrodynamics, increasing the amount of energy they require for swimming4.

Despite these findings, bands are still widely used.

Le Maho and his colleagues have now added to the debate with their 10-year study. They banded 50 king penguins selected from a population on Possession Island in the southern Indian Ocean that had already been implanted with minute, subcutaneous electronic tags.

When compared with 50 unbanded birds, those fitted with bands had around 40% fewer chicks and a 16% lower survival rate over the study period.

Le Maho says that new technologies, such as the subcutaneous tags, have not become as widespread in ecology as they have in Earth science. "Still today you will find that most US studies on Adélie penguins use flipper banding," he says.

And his co-author Claire Saraux, also at the University of Strasbourg, adds that, "Even if there is a difference between species, the drag effect is going to be there for every bird".

Double trouble

Norman Ratcliffe, a seabird biologist with the British Antarctic Survey in Cambridge, UK, says that his employers stopped fitting bands and removed old ones in the 1980s, when evidence of harm first surfaced.

"Evidence is emerging which suggests that flipper bands do have, in most circumstances, adverse effects on demography and behaviour," he says. "The onus is on the people who are running those studies to test whether there are effects of flipper bands and demonstrate their results are robust."


However, not everyone agrees. Dee Boersma at the University of Washington in Seattle is one of the United States' leading penguin researchers.

Although she has found that double bands are harmful to female Magellanic penguins (Spheniscus magellanicus), she has found no major problems with single bands, even after birds have been wearing them for 15 years5.

"All bands, all penguins species and all locations are not the same," says Boersma. "If conclusions about one bad type of band could be expanded to include all bands, all penguins and all places, the science might be easier but the flaws would be fatal."

See also the Nature Video 'The flip side of flipper bands'. 

  • References

    1. Saraux, C. et al. Nature 469, 203-206 (2011). | Article
    2. Le Bohec, C. et al. Proc. Natl Acad. Sci. USA 105, 2493-2497 (2008). | Article | PubMed
    3. Wilson, R. Nature 469, 164-165 (2011). | Article
    4. Culik, B. M. et al. Mar. Ecol. Prog. Ser. 98, 209-214 (1993). | Article | ISI
    5. Boersma, P. D. & Rebstock, G. A. J. Field Ornithol. 81, 195-205 (2010). | Article | ISI
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