In step A king penguin with a tracking band on its flipper walking among other adults and juveniles on the sub-Antarctic island of Crozet. (AP Photo/Nature, Benoît Gineste)Penguins harmed by tracking bands: Study

Bands attached to penguins’ flippers have helped scientists track their movement and migration for 50 years. The small identification tags are visible to researchers through binoculars from 100 feet away. Now, a new study reports the seemingly innocuous bands have a significant effect on penguin mortality. Over a decade, flipper-banded penguins produced 39 per cent fewer chicks and had a 44 per cent lower survival rate, compared with penguins that did not have bands but had microchips inserted under the skin, according to the study, which appears in the journal Nature.

That’s because the bands cause drag as penguins swim, and they are unable to gather food as efficiently for themselves or their chicks, said Claire Saraux, the study’s lead author and a biologist at the French National Centre for Scientific Research and the University of Strasbourg.

Saraux and her colleagues monitored 100 king penguins, half with flipper bands, on Possession Island in the sub-Antarctic Crozet Archipelago. How well penguins are doing is thought to be an indicator of climate change, so a better monitoring system could be critical. One solution might be to use microchips, as Saraux and her colleagues did. The chips weigh significantly less than a band. 

Sindya N Bhanoo
New York Times News Service

Food-conscious koala

Thought only humans are choosy about what they eat? Koala bears are also particular about their food. They are the pickiest marsupials around. They have evolved to feed exclusively on the leaves of eucalyptus, and they are highly selective when it comes to species and even individual trees they visit. The bear checks for many factors, including taste, to make its selection. To define palatability, the researchers tested leaves on captive koalas and recorded how much they ate. They found that the koalas ate less foliage when it contained lots of lipid-soluble phenolic chemicals. They also noted that koalas spend more time in large trees. Trees were visited more often if they were surrounded by smaller, less palatable trees or by larger, more palatable trees. This can help ecologists map habitats of animals.

Lakes too are warming

Earth’s largest lakes have been warming in the past 25 years due to climate change. Researchers analysed satellite data of 167 lakes since 1985 to measure surface temperatures. They found an average warming rate of 0.45°C per decade, with some lakes warming as much as 1°C per decade. The most consistent area of warming is northern Europe. The highest surge in temperatures were reported in mid to high latitudes of the Northern Hemisphere.

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