Elephant bird regains title: largest bird ever
History has not been kind to the elephant bird of Madagascar. Standing nearly 10 feet tall and weighing up to 1,000 pounds — or so researchers believed — this flightless cousin of the ostrich went extinct in the 17th century, thanks in part to humans stealing their massive eggs, either to feed their own families or to repurpose them as giant rum flasks. Or both.
More recently, the bird’s designation as the heaviest in history was challenged by the discovery of the slightly larger, unrelated Dromornis stirtoni, an Australian flightless giant that went extinct 20,000 years ago.
But a new study seeks to restore the elephant bird’s heavyweight title. After taxonomic reshuffling and examination of collected elephant bird remains, researchers say that a member of a previously unidentified genus of the birds could have weighed more than 1,700 pounds, making it by far the largest bird ever known.
Over the centuries, scientists have competed to collect and display the largest elephant bird bones. But, “nobody’s done any real cohesive research on these birds,” said James Hansford, a paleontologist at the Zoological Society of London and lead author of the study, resulting in a taxonomic muddle for the feathered giants. As a result, more than 15 elephant bird species had been identified across two genera.
Hansford traveled the globe with a measuring tape examining thousands of elephant bird bones. He then used data on modern birds and algorithms to help determine how large the birds might have grown.
His conclusion, published recently in the journal Royal Society Open Science, is that there were actually three genera of elephant bird rather than two, and four species rather than 15.
One of those species, Aepyornis maximus, had long been considered the heaviest elephant bird, until a British scientist in 1894 claimed to have discovered an even larger species, Aepyornis titan. Other researchers dismissed the finding, saying A. titan was simply an unusually large member of the A. maximus clan.
But Hansford reports that A. titan is not only its own species but a separate genus of much larger elephant bird, as evidenced by the distinct size and shape of all three limb bones. He has named the species and genus Vorombe titan; vorombe is a Malagasy word meaning “big bird.”
Green crabs menace Maine’s coast
In the mid-1800s, European green crabs hitched a ride on boats and came to the United States. But over the past few years, a genetically different European green crab from Nova Scotia, Canada — one that is more combative and more destructive of ecosystems — has appeared off the coast of Maine.
“To use nice words, I would simply describe them as highly aggressive,” said University of New England professor Markus Frederich. In the lab, he and his students use more colorful language while working with the crabs, which come at them, pincers up.
The aggressive nature of the Canadian hybrid poses another problem for Maine, which already struggles to defend its soft-shell clam population from Maine green crabs.
The green crabs from Canada have been described as the “cockroach of the sea.” Green crabs are voracious predators that can withstand changing temperatures, low salinity and low oxygen levels. They eat oysters, can prey on lobsters in groups and have been known to turn on each other, experts said.
Researchers worry that a changing climate and warming waters could make conditions more favorable for them.
Green crabs slice through eelgrass, an important habitat for other sea creatures, Frederich said. Preliminary research shows that the aggressive crabs from Canada wreaked more havoc on eelgrass and soft-shell clam populations compared with their Maine counterparts.
Attempts to reduce the impact of the crabs have included creating products out of them, such as commercial compost and food paste. Fences have also been placed in the water to protect soft-shell clam populations.
Brian Beal, a professor at the University of Maine at Machias, said the crabs from Canada have no native predator in North America, and only cold winters keep their population in check. Rising temperatures in the Gulf of Maine mean “conditions are becoming more and more favorable for green crabs to survive and populate areas,” he said.
Killer whales face dire PCB threat
Most people thought the problem of polychlorinated biphenyls — known as PCBs — had been solved. Some countries began banning the toxic chemicals in the 1970s and 1980s, and worldwide production was ended with the 2001 Stockholm Convention.
But a study based on modeling shows that they are lingering in the blubber of killer whales — and they could end up wiping out half the world’s population of killer whales in coming decades.
“It certainly is alarming,” said Jean-Pierre Desforges, a postdoctoral researcher at Aarhus University in Denmark and the lead author on the study published recently in the journal Science.
Whales sit at the top of their food chain. Chemicals like PCBs are taken up by plankton at the base of the food chain, then eaten by herring and other small fish, which are eaten by larger fish, and so on. The most at-risk killer whales are those that eat seals and other animals that are fairly high on the food chain and quite contaminated, Desforges said.
Killer whale populations in Alaska, Norway, Antarctica and the Arctic among other places, where chemical levels are lower, will probably continue to grow and thrive, the study found. But animals living in more industrialized areas, off the coasts of the United Kingdom, Brazil, Hawaii and Japan, are at high risk of population collapse from just the PCBs alone.
—New York Times News Service