ID tags handicap penguins

[blueroseaviary]

May 19, 2004

ID tags handicap penguins
Study finds that birds with flipper bands are late to breed and are less successful at it | By John Whitfield

The identification bands that researchers put on penguins' flippers seriously handicap the birds, according to research published online by a team of ecologists this week in Proceedings of the Royal Society B. In a sort of Heisenberg Uncertainty Principle for ecology, the findings suggest that the results of some studies could be unreliable and may mean that work on endangered penguin species is harming the animals it is trying to save, said authors of the study.

Banded king penguins (Aptenodytes patagonicus) arrived at their breeding colonies up to 3 weeks later than unencumbered birds, Yvon Le Maho and his colleagues found when they monitored 100 penguins living on Possession Island in the Crozet Archipelago, in the southern Indian Ocean for 5 years.

By implanting electronic tags under the skin of penguins, Le Maho's team could carry out the first long-term study comparing banded with unbanded birds. The banded penguins were also less likely to breed and produced 50% fewer chicks when they did. Chicks carrying bands had a lower survival rate, although adults with bands were no more likely to die.

The results will be controversial, said Le Maho, who works at the Center for Ecology and Energetic Physiology in Strasbourg, France. ?When you've spent your whole life banding penguins, this is difficult to accept,? he told The Scientist.

Over the past 50 years, said the researchers, tens of thousands of penguins have been banded. The team stops short of calling for a compete halt to the use of flipper bands, saying that the impact depends on the species, the place and the time they are used. But they argue that the technique should no longer be used on species for whom conservation is a concern.

The accuracy of studies on breeding, survival, and life history may now be called into question, said zoologist Boris Culik of the Liebniz Institue of Marine Sciences, Germany. ?By using these bands, you could be changing the things you want to find out,? said Culik, who was not involved in the study. ?There's always been uncertainty as to whether the effects of banding were drastic. Everyone should now be convinced that they are.?

But other penguin researchers said that flipper bands need not have a negative impact. ?We've been banding penguins for 20 years, and haven't seen big differences in mortality,? said Dee Boersma, of the University of Washington, Seattle.

Researchers usually mark a bird by putting a ring round its ankle, according to the paper. But penguins' unusual leg joints make this impossible. Instead, a metal band is placed around a flipper.

The debate on the bands' effects has run for more than a decade, said Le Maho; some groups have already stopped using them. Other researchers have suggested a band would only hamper a bird for a short time, until the animal got used to it.

Bands hamper penguins' swimming by disrupting their beautifully streamlined profile, said Culik: ?It makes a huge proportion of the wing useless.?

But Boersma, who was not involved in the study, said she believes that the main cause of damage is through bands that come partially open, wounding the bird. Her group uses a stainless steel band that she says avoids this problem; they have compared banded birds with those wearing toe tags, and found no differences. ?Not all bands are created equal,? she said.

Transponders alone cannot replace flipper bands, said the study's lead author, Michel Gauthier-Clerc of the Tour du Valat Biological Station in Arles, France. For behavioral studies, it is still necessary to identify birds by eye. Hi-tech monitoring is also much more expensive.

?Ecologists are realizing that we can't take the effects of our manipulations for granted?we're studying living organisms in natural systems, not a beaker in a lab,? said James Cahill of the University of Alberta, Edmonton. In 2001, Cahill found that by handling the plants in his experiments, he changed the amount that herbivores ate them.

The penguin study ?has enormous implications for long-term studies, and for those focused studies where people want to know where every individual is,? said Cahill, who was not involved in the study. ?This is the type of news that most scientists don't want to hear.?

Links for this article
M. Gauthier-Clerc et al., ?Long-term effects of flipper bands on penguins? Proc R Soc Lond B, DOI:10.1098/rsbl.2004.0201, May 18, 2004.
http://www.journals.royalsoc.ac.uk/o...nre=article&id =doi:10.1098/rsbl.2004.0201

Centre for Ecology and Energetic Physiology
http://www.cepe.c-strasbourg.fr

Liebniz Institue of Marine Sciences
http://www.ifm-geomar.de/info/information_e.html

Dee Boersma
http://faculty.washington.edu/boersma/

S. Jackson, R.P. Wilson, ?The potential costs of flipper bands to penguins,? Funct Ecol, 16:141-148, February 2002.
http://www.blackwell-synergy.com/lin...46/j.0269-8463. 2001.00606.x/full/

Michel Gauthier-Clerc
http://www.tourduvalat.org/news_348.htm

James F. Cahill
http://www.biology.ualberta.ca/faculty/james_cahill/

J.F. Cahill et al., ?The herbivory uncertainty principle: visiting plants can alter herbivory,? Ecology, 82:307-312, February 2001.
http://www.esajournals.org/esaonline...-abstract&issn =0012-9658&volume=082&issue=02&page=0307