Never mind canaries in coal mines, says Dee Boersma, a University of Washington biologist. Think penguins.

Oil pollution, fishery depletion, rampant coastline development – and the biggest threat of all, climate change – have all adversely affected penguin species, some of which are now in sharp decline.

“Penguins are among those species that show us that we are making fundamental changes to our world,” said Boersma, an authority on flightless birds. “The fate of all species is to go extinct, but there are some species that go extinct before their time, and we are facing that possibility with some penguins.”

In a paper published in BioScience, Boersma notes that severe population declines have been recorded at many major penguin breeding colonies. For example, in the 1980s, there were an estimated 400,000 pairs of Magellanic penguins at Punta Tombo on the Atlantic coast of Argentina; now there are less than half that number.

Similarly, the total estimated population of African penguins has dropped from 1.5 million pairs a century ago to 63,000 pairs in 2005. Populations of Adelie and Chinstrap penguins have declined 50 percent since the mid-1970s.

Verbatim

The death of the butterfly is the one drawback to an entomological career.

– Distinguished Victorian lepidopterist Margaret E. Fountaine (1862-1940)

Brain sweat

The number – 8,549,176,320 – has a rather special characteristic. Can you identify it?

Brain sweat answer

It consists of the digits 0 to 9 in alphabetical order.

Prime numbers

36 – Number of countries in crisis because of food prices

21 – Number in Africa

486.3 – World stocks of cereal in 2003, in millions of metric tons

469.3 – In 2005

405.1 – In 2008

Sources: World Bank; United Nations Food and Agriculture Organization

Datebook

Some major names in astronomy are slated to appear at the free Southern California Astronomy Exhibition July 12 and July 19 at Oceanside Photo and Telescope.

On July 12, speakers will include Scott Kardel of Palomar Observatory; Nicholas Law, the principal investigator of the LuckyCam project; and Marc Rayman, lead engineer on NASA's Dawn spacecraft.

At dusk, telescopes will be available for public stargazing, and Seth Shostak of the SETI Institute will talk about the likelihood of discovering extraterrestrial life.

Exhibition activities July 19 will include mini-astronomy seminars, telescope demonstrations and vendor displays.

For more information, visit optcorp.com.

Electron Ink

World Register of Marine Species

marinespecies.org

How many species are there in the sea? Researchers are trying to find out in a years-long Census of Marine Life. At the moment, roughly 230,000 species have been recorded, a fraction of the total. You can check the current list here.

Quirks of nature

Some pitohui birds, which are endemic to Papua New Guinea, are festooned with poisonous feathers. It's believed that the feathers, which are infused with a powerful neurotoxin, are a chemical defense, either against ectoparasites or predators such as snakes, raptors and humans. The birds probably don't produce the toxins themselves, but acquire them from eating certain noxious beetles. People handling the feathers may experience numbness, burning and sneezing.

Where in the world?

Where in the world answer

Antarctica's Erebus glacier flows down from the mountain of the same name, eventually reaching McMurdo Sound, part of the Southern Ocean. The glacier, though, doesn't stop there. The ice pushes out, creating a six-mile-long “ice tongue.” When McMurdo Sound thaws in the summer, the tongue floats on water, chunks sometimes breaking off into icebergs. The serrated edges are caused by waves eroding the edges.

Patently absurd

Helium-filled sunshade

Perhaps the inventor, Frederick Sevilla of Mesa, Ariz., spent too much time in the sun, but his idea (U.S. Patent No. 5,076,029) is still pretty heady: A flat, balloonlike structure made of lightweight material is pumped up with helium, and attached dangling cords are looped under each armpit.

Picture a flying saucer hovering just overhead.

Sevilla intended his 1991 invention to serve as a movable source of shade, but it could also, in theory, be an umbrella. And if it really rained hard, it might serve as a flotation device.

This Week in Science This week in 1900, the first directed flight of a Zeppelin was made above the Bodensee (Lake Constance) near Friedrichshafen, Germany. LZ-1 was the first rigid airship to use a large internal metal frame containing multiple cells of hydrogen gas balloons. Its overall shape was a long, uniform cylinder with rounded ends, 416 feet in length. Named after its inventor, Ferdinand Graf von Zeppelin, LZ-1 flew 18 minutes before technical difficulties cut short its debut flight.