September 19, 2012
In our October issue, Michelle Nijhuis joins wildlife biologists in searching Colorado’s caves and waterfalls for one of the world’s most mysterious bird species: the black swift. Although fewer than 100 breeding sites of the black swift are known, Nijhuis was lucky enough to see ornithologist Ron Torretta locate a black swift that had been geotagged in 2010, providing researchers with a cache of information about the wanderings of the enigmatic bird. Here are a few more of the most mysterious and elusive of the world’s bird species.
1. Night Parrot: Between 1912 and 1979, birders spotted this elusive species, native to the interior of Australia, exactly zero times—leading most scientists to believe it had gone extinct. Since then, a tiny handful of sightings of the nocturnal, yellow-green bird have occurred, and experts now estimate that the population is somewhere between 50 and 250 mature individuals. After the last verified sighting in November 2006, when park rangers in the state of Queensland turned up a decapitated specimen that had died after flying into a barbed-wire fence, the Australian government chose to keep the find temporarily secret while they searched for more night parrots, so as to avoid an influx of birders flooding the remote park in hopes of spotting one of the world’s rarest birds.
2. Ribbon-tailed Astrapia: Endemic to the forest highlands of Papua New Guinea, this bird has the longest tail feathers (in relation to body size) of any bird species, with feathers three times its body length. Unfortunately, this stunning plumage has enticed poachers; hunting, along with habitat loss, has led to the species being listed as “near threatened” by the International Union for Conservation of Nature. The species, the most recent bird of paradise to be documented, was first described by explorer Fred Shaw Mayer in 1938.
3. Palila: This species of Hawaiian honeycreeper has one particularly mysterious characteristic—it subsists almost exclusively on the seeds of the māmane plant, which contain a level of toxins that would kill any other small animal. Scientists aren’t sure how the birds digest the seemingly-lethal seeds, although the palila have been observed avoiding certain plants, indicating they might have a way of selecting seeds with lower levels of poison. In 1978, the federal government ruled that feral goats and sheep had to be removed from the palila’s only remaining habitat—the upper slopes of Mauna Kea on the Big Island of Hawai’i—since they consumed māmane plants and threatened the birds’ survival.
4. The Kakapo: Some 82 million years ago, the island of New Zealand broke off from what would become Australia, and the strange, flightless nocturnal parrot species called the kakapo began its unusual evolutionary path. In the absence of predators, it became the world’s largest type of parrot and lost the ability to fly; when European colonists introduced cats, rats and ferrets to New Zealand to control the population of rabbits, the kakapo was nearly wiped out. Now, just 126 wild kakapos live on three predator-free islands off the coast of New Zealand.
5. The Crested Ibis: Named for the crest of white plumage that extends from its nape, the crested ibis used to nest across Japan, China, Korea, Taiwan and Russia. By 1981, after years of habitat loss, just five individuals remained in the wild in Japan, and though scientists took the birds into captivity, a breeding program was unsuccessful. Now, the last remaining wild population—some 500 birds in the Chinese province of Shaanxi—is being buttressed by chicks hatched in captivity as part of a Chinese program. Although the species is still listed as endangered, scientists are cautiously optimistic that it is finally making a comeback.
May 1, 2012
We live in an age of alarming extinction, in which many species are lost in large part due to human activity. At the same time, the natural world is so complex that even after centuries of research, scientists are still rapidly discovering new species everywhere from mountain tops to rain forests to the ocean floor.
This paradox is aptly illustrated by an announcement made yesterday: 24 new species of lizards, known as skinks, have been discovered in the Caribbean islands. But half of them may be close to extinction, and some may already extinct in the wild.
The research was conducted by a team led by Blair Hedges, a biologist at Penn State University and one of the world’s foremost experts at identifying new forms of life. Previously, Hedges has been involved with the discovery of what were then the world’s smallest snake, lizard and frog. The two dozen species named in this paper, published in the journal Zootaxa, constitute one of the largest mass discoveries of lizards in centuries.
To identify the many species of skinks (formally, members of the family Scincidae), Hedges and his team examined specimens housed at zoos and conservation centers around the world. By comparing taxonomic features of the lizards (such as the shapes of scales) and using DNA analysis, they determined that there are a total of 39 distinct species of skinks that live in the Caribbean—6 species that were previously recognized, 9 that had been named long ago but had been considered invalid and the 24 entirely new ones.
“Now, one of the smallest groups of lizards in this region of the world has become one of the largest groups,” Hedges said in a press release. “We were completely surprised to find what amounts to a new fauna, with co-occurring species and different ecological types.” He has determined that the skinks came to the Americas roughly 18 million years ago, likely arriving from Africa on floating rafts of vegetation.
How did the skinks go unnoticed for so long? Hedges speculates that because large numbers of skinks had already disappeared by the start of the 20th century, scientists, tourists and local residents have been much less likely to encounter them in the years since. Additionally, many of the characteristics that distinguish the species from one another have been overlooked or weren’t detectable until now, especially those indicated by DNA analysis.
The researchers determined that the skinks have long been most threatened by an exotic intruder: the mongoose, introduced from India to Cuba in 1872 with the intention of reducing rat populations in sugarcane fields. Rat populations were partially controlled, but by 1900, nearly half of the islands to which the mongoose had spread were also without skinks, and the remaining lizards have dwindled in population ever since. Additionally, the researchers note, current human activities such as forest removal are likely contributing to the skinks’ endangered status. The research team hopes that their data will be used to plan future conservation efforts.
Theoretically, if you’re in the U.S. Virgin Islands, Trinidad and Tobago, or Martinique, you might try looking for a skink. But because each of the species is remarkably rare—with even the non-endangered ones qualifying as vulnerable—it’ll certainly be difficult. Above all, if you do want to find one, hurry up: there may not be much time left.
January 25, 2011
Clouded leopards—named for their large, cloud-like spots—are rare. They are medium-sized (a bit bigger than a housecat) tree dwellers with big teeth and big paws that let them hang upside down among the foliage. In 2006, scientists used DNA studies to determine that there were two species of clouded leopards: Neofelis nebulosa, which lives on the Asian mainland and is the subject of a breeding program at the National Zoo (producing some of the world’s most adorable kittens), and Neofelis diardi, the Sunda clouded leopard, found on the islands of Borneo and Sumatra.
Now a group of researchers led by the Leibniz Institute for Zoo and Wildlife Research in Germany has determined the the Borneo and Sumatra populations are really two separate subspecies, splitting this rare kitty into two even rarer varieties. The scientists, reporting in Molecular Phylogenetics and Evolution, analyzed DNA from 15 leopards on Borneo and 16 on Sumatra and also examined the skulls and coats of museum specimens. They found that the kitties on the two islands looked very similar on the outside but had significant differences in skull shape and in their genetics.
The scientists aren’t certain about the events that led to the evolution of the various species and sub-species, but here’s what they propose: The ancestor species to all modern clouded leopards was living in Southeast Asia when the super-volcano Toba erupted on Sumatra around 75,000 years ago, possibly plunging the Earth into a years-long volcanic winter. Two populations of clouded leopards survived—one in southern China, which evolved into the modern-day clouded leopard, N. nebulosa, and one on Borneo, which became the Sunda clouded leopard, N. diardi. When sea level was low, some of those Sunda clouded leopards were able to travel back to Sumatra, but when the last Ice Age ended, around 10,000 years ago, and sea levels rose, Borneo and Sumatra were once again isolated from each other and the two populations were left to evolve into sub-species apart from each other.
October 8, 2010
Ten years ago a group of marine scientists founded the Census of Marine Life and set out to answer three questions: What did live in the oceans? What does live in the oceans? What will live in the oceans? More than 2,700 scientists would participate in the Census on more than 540 expeditions around the world. They found nearly 250,000 marine species, upping the count by about 20,000; they estimate there are at least a million marine species in the oceans and tens to hundreds of millions of kinds of microbes.
There were schools of fish the size of Manhattan and animals that commuted like clockwork up and down the water column. There were living things in every bit of ocean the scientists looked at, from the deep dark depths to frozen seawater to waters so hot they would melt lead. There were mats of bacteria that extended for hundreds of kilometers.
But there was bad news, too. Scientists documented what used to live in the seas by checking historical records of sightings and catches, and also restaurant menus. Many species had declined in numbers, sometimes within one human generation. Phytoplankton, which sits at the base of the food web, has also declined in the last century.
This first Census is officially done, but it wasn’t complete. The Census has no records for about 20 percent of the ocean’s volume, and records are sparse for some large areas.
But the Census has already had a huge effect, not only in introducing us to thousands more of the species with which we share the planet (some were featured recently in our story Weird Creatures of the Deep), but also by setting a baseline against which we can measure our impact on the oceans. We fish some species too much, pollute the waters and change ocean chemistry through climate change. At least now we can get a good idea of how bad the situation is becoming.
September 24, 2010
Call them panthers, mountain lions, cougars or pumas, the Americas’ largest cat species has been dwindling in eastern North America for hundreds of years. They were extirpated from everywhere but some shrinking habitat in Florida between Naples and Miami. And even there, the panthers were not doing well. By the mid-1990s, the population consisted of just a couple dozen adult cats, and they were suffering from the problems of inbreeding: low reproduction rates, sperm quality and testosterone levels; heart defects; kinked tails; and high loads of parasites and pathogens. It wasn’t looking good for the Florida kitties.
In 1995, conservationists tried to bolster the Florida population by introducing eight female panthers from Texas. The two subspecies used to intermingle, so transferring a few females would restore some of the natural gene flow. Fifteen years later, scientists are declaring the program a success. The addition of just a few new kitties to the gene pool resulted in a more diverse population that no longer suffered from the problems of inbreeding. And the population tripled in size. (The study appears in today’s issue of Science.)
Florida’s panthers, like so many cat species, still face serious challenges to their survival, including habitat loss and disease. But it’s heartening to see that relatively simple solutions—transferring a handful of cats combined with efforts to preserve habitat and reduce deaths from car accidents—can have such a positive effect on a population.
Earlier this week, the BBC announced the discovery of tigers in Bhutan living high above the treeline, far from where anyone had expected the cats could survive. Scientists hope to create a corridor connecting small, scattered tiger populations, such as this one in Bhutan, with others across much of Asia. The idea being that, like the Florida panthers, Asia’s tiger populations would get stronger from increased genetic diversity.
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