Penguins trial plastic tag

Thousands of penguins were moved because of the spill

An innovative plastic tag has been developed by British researchers to help keep track of penguins.

The silicon-rubber band is claimed not to interfere with the birds' natural behaviour as much as old metal tags.

The new tag is a snug fit which should not impede swimming

The new design, which is slipped over the animals' wings, is being tested on penguins rehabilitated after the June 2000 oil spill near Robben Island, South Africa.

A massive operation was launched at the time to retrieve oiled birds; 20,000 more were moved to keep them out of harm's way.

The plastic tags, which are featured on the BBC's Tomorrow's World science programme, will assist biologists as they try to establish how well penguin colonies at Robben and nearby Dassen Islands are recovering.

Swimming problems

The new bands are the brainchild of Dr Peter Barham, a reader in polymer physics at Bristol University.

The long-time penguin-watcher used his students to develop the tracking tool when he heard other scientists raise concerns about the performance of the traditional steel tags attached to flippers and wings.

Some researchers feared the old rings might be injuring the birds, and could even be interfering with their swimming success - which would have implications for catching food and therefore for breeding.

"Some reports suggest the steel tags cause significant hydrodynamic drag - it can take up to 20% more energy for penguins to swim," Dr Barham told BBC News Online.

It is said steel tags can also develop sharp edges, wear away the feathers and even catch on branches of shrubs growing where penguins nest in more temperate zones.

Trials needed

"The new band is a snugger fit because it opens and closes. And because it sits close to the body, we hope that it is hydrodynamically good.

"We've done tests in tanks with wooden penguins and dragged them through the water - but that's not the same as the wild and that's why we're now testing the bands on Robben Island."

Doubts surround the performance of steel bands

The polymer chosen by the Bristol scientists is a variant on the familiar bathroom sealant.

"It's a particularly good one, though," Dr Barham said. "It will easily stretch to six times its own length and snap back, which means you can open it up, slide it up a penguin's flipper and let go - it's very easy to put on and that's important."

Dr Barham says it will be several years before the plastic tags can be used on a much wider scale.

"At the moment things look okay, but you have to see some penguins wearing these tags for two or three years without any harm coming to them before you are sure the design is safe for other birds."

UK television viewers can see Tomorrow's World on BBC One at 1930 BST on Wednesday, 1 May.