Banding hurts penguins, says new study in journal Nature

Text and photo by Sally Kneidel, PhD 

Attaching bands to birds is a longstanding method of studying bird populations. The bands allow researchers to collect data on birds' movements and longevity.

But scientists have been debating for 30 years whether bands on penguins may hurt the birds.  On aquatic or marine birds, such as penguins, bands are generally attached to the front base of a flipper rather than to a leg.

Note metal band on this African (Jackass) Penguin, on front of left flipper. Photo: Sally Kneidel, southern tip of Africa [click on photo to enlarge it]

Zookeepers noticed as early as the 1970s that flipper-bands can injure molting penguins.  It's now suspected that bands also create drag when penguins are swimming, which could interfere with prey capture.

A new study published Jan 12, 2011 in the journal Nature provides strong evidence that bands do hurt penguins' survival and reproduction. Yvon Le Maho of the University of Strasbourg in France and his colleagues banded 50 King Penguins from Possession Island in the southern Indian Ocean. These 50 birds had already been implanted with "minute" and subcutaneous electronic tags. Over the course of a 10-year study, Moho and colleagues found that the banded penguins produced 40% fewer chicks and had a 16% lower survival rate compared to 50 nonbanded penguins

Subcutaneous tags, while safer, are a relatively new technology and not yet widely used in ecological studies.  "Still today you will find that most US studies on Adélie penguins use flipper banding," says Le Maho.  But his new publication may encourage the increased use of subcutaneous tags instead.

Climate change studies at stake

There's a wider issue at stake than the birds' welfare: studies on penguins are often used to gauge the effects of climate change on ecosystems. If a study suggests that a slight warming of ocean waters reduces penguin survival, how much of the difference could actually be due to banding effects?

For the birds and for the sake of our climate data, subcutaneous tags that create no drag should replace flipper-banding in future studies with penguins.

Keywords: penguins, bird banding, flipper banding, climate change, subcutaneous tags