Has the ivory-billed woodpecker left the building?

Watercolor painting of ivory-billed woodpeckers from Audubon's Birds of America, 1826.

Imagine waking up one morning to real film footage of a duckbill dinosaur wandering around the Great Plains. Your reaction might be similar to that of birders around the world when Science magazine reported in 2005 that the ivory-billed woodpecker, thought for 60 years to have been extinct in the United States, still existed.

A forest bird of legend

The woodpecker entered birder and ecologist lore when its numbers declined in the early part of the 20th century. Its habitat was bottomland forest in the southeastern United States and Cuba, and its niche included drilling into mature trees. When people came along, logging away the woodpeckers’ homes, the bird appeared to vanish. By the 1920s, we thought it had disappeared forever, although in 1943, there was a single confirmed sighting of a lone female, flying over the stumps of an old-growth forest. She became a central figure in a PhD thesis in 1944. Then for 60 years, silence.

False calls

Well, not complete silence. There were many reports of sightings, but most were traced to another woodpecker species, the pileated woodpecker. The ivory-billed woodpecker differs distinctly from its pileated cousin in beak color, in having white patches on its back when perched, and in its size and the solid-black crest of the female. It has a three-foot wing span, which is huge for a woodpecker, and can grow as large as 20 inches long. It is a big, beautiful, and surprising bird, with a bright red crest on the males that must be startling to see among the cypress of a bottomland forest.

A mesmerizing obsession

Birders, possibly the most obsessive of any taxon fan club, had long wandered into the swampy bottomlands of Arkansas and Louisiana, trying to find ivory-billed woodpeckers. There was a confirmed sighting in Cuba in the ‘80s, and over the decades, people have claimed sightings or reported having heard the ivory-billed’s call. Professionals and amateurs alike have waded among snakes and fought off bugs, playing tapes of the call and listening for a response. At one point, searchers found a nest that had an ivory-billed look to it and trained a remote-sensing camera on it, but saw nothing.

And then in 1999, a kayaker thought that he had seen a pair of the birds. His report received serious attention from the government, local papers, and academic groups interested in the woodpecker both for its inherent beauty and for its status as a symbol of the price of our destructive tendencies. Soon, the old forests of the southeast were crawling with ornithologists, all hoping to catch a glimpse, take a picture, and emerge with definitive proof that a bird long thought to be extinct had survived.

The beat of the forest, revived?

Some people heard the drumming sounds the woodpecker is known to make. A handful of people who really knew their woodpeckers reported sightings. But it was a four-second video of the shy, reclusive bird that clinched it. The video is short and blurry, taken from a kayak in late April of 2004 on a camcorder. But even its poor quality couldn’t hide the distinctive markings and features of the ivory-billed woodpecker.

The confirmation set the world of ornithology astir, but it also reverberates among ecologists and environmentalists. The fact that at least one male ivory-billed woodpecker exists indicates that at least one breeding pair must have survived into the 1990s because the birds live 15 to 20 years at most. And it also might have meant a second chance for us and the woodpecker. Unfortunately, according to a recent report from Cornell researchers who have spent five years looking for more signs of the bird, “it’s unlikely that there are recoverable populations” of the bird where they’ve been searching.

The lovely bones: Terra preta to save our terra firma?

Charred bones set to save the world?

The Amazon river basin is home to the famous Amazonian “dark earth,” or terra preta, which recently made the news as more proof of large civilizations in the tangled Amazon forests.  This soil is renowned for its fertile properties, its loose consistency, water-holding abilities, and of course, its dark color. The people who used this earth generations ago—as many as 3000 years ago, according to one researcher—may have had no active interest in “greening” the planet, but they were very interested in getting a good crop yield for their efforts. Terra preta probably gave them just that.

Ancient farming wisdom

Somewhere along your educational path, you may have learned a few tips about farming. Rotate your crops. Let fields take a break. Till the soil. What you may not have understood as clearly were the natural processes that drove this farming wisdom.

When farmers turn over the soil, they loosen it. Earth happens to be the largest sink of carbon on terrestrial Earth, and when we move it around, some of that carbon gets released. When we try to fertilize it using dead and decomposing organic matter—compost, manure—this approach works in the short term to restore some nutrients, but microorgansims make pretty quick work of these organic remnants, returning carbon to the atmosphere again as carbon dioxide.

Thus, standard farming techniques of tilling and fertilizing and applying manure are short-lived efforts to keep the soil nutrient rich enough for planting. If nutrients are low, crop yield will be, too. And then there’s the water consideration; if the soil holds too little water or too much, that will also affect crop yield.

Magical fairy dust for crops

These factors all combine to make the terra preta soil look like magical fairy dust for crops. The soil actually is charcoal—or, in the lingo of the scientists who work with it, biochar. It is made from the rapid, pressurized burning of dead stuff—bones, tree bark—and manure. Pack it all into a metal container with a little hole for some pressure to escape, heat it to about 400 degrees Celsius, and you’ve made yourself some biochar. It apparently looks just like the charcoal you’d use at a cookout, but it has many more uses.

The carbon in the biochar is pretty inaccessible to microorganisms that would break it up, so it lasts a lot longer in the soil than your average, uncharred manure. In fact, it’s so long lasting that it’s still around in the Amazonian river basin long after the ancient farmers who used it disappeared. In addition to being a nutrient-rich and nutrient-tight source of carbon, biochar also is quite grabby with water, holding much more water than your average soil sample. That feature means that less water is required to grow crops in a biochar-laced field than would be needed in a regular, every-day kind of field.

Could soil invented in the Amazon save the Amazon?

Plants growing in the stuff do so faster, more robustly, and in greater numbers, primarily because of the rich nutrient source the biochar provides. Research indicates that the optimum combination is biochar plus fertilizer, which gives the greatest crop yield compared to either alone or neither. Using biochar could dramatically enhance global crop yields while decreasing water use and without adding a single acre of cropland. Using soil invented in the Amazon to save the Amazon rainforest has a nice “the circle is complete” aspect to it.

Although biochar has the drawback of having to be made and transported, its benefits to the planet don’t end with crop yield and water savings. The smoke generated from its preparation, in a process called pyrolysis, can be collected and used to form bio-oil, a form of renewable energy. In addition, biochar has potential as a sponge to soak up phosphates and nitrates from fertilizers before they reach our waterways, a sort of barrier against pollution. Last, this dark, magical fairy dust not only reduces carbon dioxide emissions from cropland but also significantly decreases methane and nitrous oxide emissions, both greenhouse gases that are far more potent than carbon dioxide but get considerably less press.

Think you’re eating snapper? Think again

Grad students learn PCR, uncover fish fraud

It’s a great thing if you get your name published in the journal Nature, the pinnacle of publishing achievement for a biologist, while you’re still in school. Such was the fate of six graduate students participating in a course designed to teach them DNA extraction, amplification, and sequencing. They identified a real question to answer in the course of applying their techniques, and their results got them brief communication in Nature and national recognition. Not bad; I hope everyone also earned an “A.”

The group, led by professors Peter Marko and Amy Moran at the University of North Carolina-Chapel Hill, suspected that fish being sold as red snapper in markets in the U.S. were actually mislabeled, in violation of federal law. This kind of fraud is nothing new; marketers have in the past created “scallops” by cutting scalloped-shaped chunks from the wings of skates (part of the cartilaginous fish group), and have labeled the Patagonian toothfish as Chilean sea bass.

Protections can drive fraud

Such mislabeling has far-reaching implications, well beyond concerns about defrauding consumers of the fish they want. If fisheries and fish dealers are reporting their catches as red snapper or scallops or sea bass when they are, in fact, other marine species, then data on the abundance and distribution of all of these species will be misleading. Red snapper, Lutjanus campechanus, was placed under strict management in 1996, a move that gave incentive to the fishing industry and retailers to mislabel fish. Some experts suspect that many fish under heavy restriction end up with their names on a different species for market.

Who is responsible for the mislabeling? Fishermen pull in their catches and identify them on the boat or at the dock. The catch goes to a fish dealer, who is also responsible for reporting what species and how many of each species were caught. This report becomes the official number for the species. The dealer then sends the fish on to the retail market, where it is sold in stores and restaurants. Misidentification on the boat or dock is one reasonable possibility because some of the species identified in the North Carolina study frequent the same types of habitat, primarily offshore waters around coral reefs. These species, which include vermillion snapper and silk snapper, do look very much like red snapper, although there are some identifiable morphological differences.

One filet is just like the other?

So misidentification could be an honest mistake or purposeful change at the boat or dock, or it could be a willful relabeling at the restaurant or market. By the time a fish is processed, it consists essentially of a filet that is indistinguishable from that of other, similar fish. Hapless consumers end up paying twice as much for silk snapper, thinking they’re getting the pricier red snapper, instead.

But the DNA sequencing the North Carolina group performed not only turned up species closely related and very similar to red snapper, but also uncovered some sequences that have no identity with those of known species in gene databanks. In other words, fish of unknown identity are being caught, sold, and eaten as red snapper before we even have a chance to document what they are, their habitats, or their numbers.

Mislabeling is rampant

The grad students and professors also found that some of the fish being marketed as Atlantic red snapper were, in a few cases, from the other side of the planet, including the crimson snapper, which occurs in the Indo-West Pacific. All told, they found that 77% of the fish samples from stores in the eastern and midwestern U.S. were mislabeled as red snapper.

One way to prevent such mislabeling is to require identification of the country of origin of fish sold at market. The USDA has instituted such a program, although confusion will likely persist about fish caught in international waters. And the mislabeling isn’t only a U.S. phenomenon.

In the meantime, how do you know you’re getting red snapper? Some fish ecologists recommend avoiding it entirely because it still suffers from overfishing; however, one way to know your fish is to ask for it with the skin on, or completely intact. If you’ve got a smart phone, you can just look up the image and compare. Alternatively, you could just order the salad.

Sad update: Baby red panda has died

This update on the baby red panda from a news release via the National Zoo:

An animal keeper at the Smithsonian’s National Zoo discovered a recently born red panda cub lifeless yesterday during evening animal rounds. The 21-day-old cub was immediately transported to the veterinary hospital where a veterinary team confirmed his death. Born June 16, this male was the first cub for parents Shama and Tate and the first cub born at the Zoo in 15 years.

Zoo keepers had closely observed the cub since his birth. First-time mother Shama had moved the cub around the outdoor exhibit instead of keeping the cub in a nest box, as would be expected. As a result of Shama’s behavior, the exhibit was roped off to the public in order to provide her with peace and quiet. Animal care staff weighed the cub regularly, observed and reviewed the behavior of the cub and parents at least twice daily and volunteers monitored the behavior in-person and via camera several hours each day.

Due to the recent extreme heat, keepers were extra vigilant maintaining the animals’ cooling centers (chilled spaces within the exhibit). Nonetheless, there is a 50 percent mortality rate for red panda cubs born in captivity. Pathologists performed the necropsy last evening but the definite cause of death was not evident. Additional testing, including histopathology, is underway and should provide additional information.

The National Zoo has been breeding red pandas successfully for 48 years. Since 1962, 184 cubs have been born at both the Zoo and the Smithsonian Conservation Biology Institute in Front Royal, Va., with a mortality rate of about 40 percent, below the national average. Currently there is one cub at the Front Royal facility.

“This is an enigmatic and important species,” said Dennis Kelly, director of the National Zoological Park. “We’re deeply disappointed to lose this cub but there are inherent risks in the conservation of rare species. Our cumulative breeding and research success has positioned the Smithsonian’s National Zoo as one of the leaders in the field of red panda conservation. We’ll stay the course until this animal is no longer listed as vulnerable.”

Red pandas breed once a year and animal care staff anticipate that they will breed again next year.

Awww. Baby red panda

It was love at first sight for Shama and Tate, the red pandas at the Smithsonian’s National Zoo, and now, nearly 1½ years after they were introduced, the pair has a cub as evidence of their strong bond. On Wednesday, June 16, Shama gave birth to a single cub—the first for both of the Zoo’s red pandas (Ailurus fulgens) and the first red panda cub born at the National Zoo in Washington, D.C., in 15 years.

Red pandas have a baby. It’s very cute.

The National Zoo is celebrating its first birth of a red panda in 15 years. The history of the red panda–at least, of its classification–is complicated. More on that in a mo. What’s significant here is its current situation. Thanks to habitat loss, the species has declined in the wild to fewer than 2500 individuals, and it is endangered. So a birth–especially between an apparently happy couple with a strong mutual attraction–is a success for the zoo and for red panda conservation, too.

The proud mother was born at the Smithsonian Conservation Biology Institute in Front Royal, Va., and more than 100 surviving cubs have been born at both this research facility and the Washington, D.C., campuses since 1962.

Panda or raccoon?

Taxonomists–the folks who classify organisms by relatedness–have had a conundrum on their hands with the red panda. You’d think that the name says it all: it’s a panda, right?

Well, no. Nothing’s ever that easy in taxonomy. For some time, arguments that it was a relative of the raccoon held weight. But the animal has some strong panda-like traits, including an affinity for bamboo and similar habitats to the giant panda. But they differ in their far more diverse diet and greater habitat distribution.

The panda’s thumb

The giant panda has a faux thumb that’s really just a bone extension of the wrist bones. It’s not an opposable thumb like the one primates have, but the giant panda uses it in a thumb-like way. The red panda happens to share this odd trait. They also share many similarities in their DNA, which ended in the red panda briefly joining the bear family.

So, is it a panda or a raccoon?

The species also has some commonalities with the raccoon, including the ringed tail and more diverse diet compared to the giant panda, one that includes a taste for bird eggs. For these reasons, it also has been classified into the raccoon family. So, which family is it?

It’s neither. While the red panda has now been classified as a distant relative of the giant panda–the bamboo! the “thumb”!–it falls into its very own family, the Ailuridae, of which the red panda, or Ailurus fulgens, is the sole member. Unlike bears, this species arose in Asia and never made the trek to the “new world.”

Interesting note, the snow leopard–another severely endangered species–is their sole wild predator.

Pesticide link to ADHD

It’s correlation, not causation

A common pesticide and metabolites have been linked in a large study to ADHD, an attention deficit disorder characterized also by hyperactivity and impulsivity. ADHD has previously been associated with specific genes and even hailed as a one-time advantageous evolutionary adaptation. But many neurological differences likely will trace to an interaction of genes and environment, or, in fancy science talk, a multifactorial causality.

But it’s also not a surprise

This study looked at metabolites in the urine of more than 1000 children, 119 of whom had ADHD. It’s not mechanistically outre to think that pesticides designed to send a pest’s nervous system astray might have a similar effect on vertebrate systems. But this study showed links, not mechanisms, which often is a necessary first step to justify further pursuing a hypothesis. The researchers found that levels of specific metabolites of organophosphate pesticides are associated with an increased risk–by as much as two-fold–of developing ADHD.

Join the ever-expanding club

If further research does identify a mechanistic tie to this identified correlation, then these pesticides will join an ever-growing suite of chemicals we’ve introduced into the environment that influence our endocrine and neural systems. These chemicals are called endocrine disruptors.

Recorded “bee alarm” calls send pachyderms packing

Elephants are terrified of bees

Forget about the mouse freaking out the elephant. What these land behemoths fear most may be bees. Researchers report in PLoS ONE that African elephants live in such terror of African bees that the pachyderms have a specific alarm call that means “Bees!” Recordings of the call could send herds stampeding, even with no bees in sight or earshot.

Birds do it, prairie dogs do it, and so do elephants

Vulnerable vertebrates living in social groups often have calls specific to danger. Prairie dogs throw up little arms and let out a whoop that means “Hawk!” or “Snake!”. Some primates and birds also have vocalizations specific to certain threats. But why do elephants, with lions as their only non-human predator, fear bees so much? A swarm of angry African bees can sting their soft parts around the eyes and mouth, and the hide of young elephants isn’t tough enough yet to withstand the stingers.

Rumble in the jungle, er, savannah

When a bee threat is detected, the elephants emit a particular rumble (listen here), just one of the many vocalizations these social animals use to communicate with each other. Subtle variations in this rumble, which elephants may produce by small adjustments in lip and tongue, can send a pachyderm pack running as though a hive of angry bees were on their trail. But another small adjustment can leave most of them standing there, staring. These subtle changes may even cue the herd to the nature of a specific danger, as is the case with other vertebrate groups that sound alarm calls.

Other differences may not be so subtle. While bees get a rumble from the elephants, lions get an unmistakable elephantine reception that includes threatening roaring and trumpeting.

The mysterious reproductive life of the giant panda

Photo credit: Mehgan Murphy, Smithsonian’s National Zoo

National Zoo’s giant panda had pseudopregnancy

National Zoo officials announced today that Mei Xiang (link has Panda Cam!), who had been monitored for several months for pregnancy, was not pregnant after all. Instead, she was experiencing a common feature of panda endocrinology, the pseudopregnancy.

Panda pseudopregnancy a common event

How could officials not be sure for months about whether or not the pregnancy was real? Panda pseudopregnancy so perfectly mimics an actual pregnancy that even hormone levels follow those of a real gestation. Staff had been monitoring her by ultrasound and blood testing, and even though ultrasound had yet to show a viable fetus, whether the pregnancy was real or pseudo was not confirmed until the hormones wrote the final chapter.

Pseudopregnancy hormones like pregnancy hormones

Late this month, Mei Xiang showed a drop in progesterone hormone. When hormone levels hit baseline in a possibly pregnant panda, one of two things can happen: a birth, or confirmation of pseudopregnancy. The progesterone decline set the clock on a 24-hour watch to see if Mei Xiang would bear a cub. She didn’t.

Ovulation once a year!

Giant pandas ovulate only once a year. Regardless of whether conception occurs, the female panda will appear pregnant, behave as though she is pregnant, and register the hormone patterns of pregnancy. If conception does not occur in that one annual opportunity, a female panda will almost always enter into a pseudopregnant state. Mei Xiang has done that five times. She’s also experienced a genuine pregnancy, bearing a cub in 2005 that now lives in China as part of a panda breeding program.

Panda soon to be back for public viewing

Mei Xiang has been sequestered during her pseudopregnancy, but her habitat at the zoo will now open again for public viewing. During her pseudopregnancy, her behaviors included reduced activity and appetite. These are now both expected to increase.

For your consideration

Pandas have some unusual life history strategies, including being food specialists and often accidentally suffocating their offspring. And, it appears that many ovulations result in pseudopregnancy. What might be an explanation for why pandas are so prone to entering a pseudopregnant state if conception does not occur? Could the behaviors that accompany the pseudopregnancy have anything to do with it?

In pandas, the hormones of a pseudopregnancy are similar to those of a real pregnancy. What pathways underlie the female’s production of these hormones of pseudopregnancy?

Women can also experience pseudopregnancy, sometimes referred to as “hysterical pregnancy.” It can even involve abdominal distention and in some cases, hormonal changes. What are some of the physiological underpinnings of a pseudopregnancy in women?

Finally, dogs and mice are also known for having pseudopregnancies. Do you think the pressures that result in these pseudopregnancies are similar to those that result in a false pregnancy in the panda? Why or why not?

Death by cat food

Introducing the cane toad:  a very bad decision

Since their introduction into the Australian landscape many decades ago, cane toads have devastated local flora and fauna. The idea was that they would eat the cane beetle, which threatened sugar cane crops. As it turned out, the thousands of introduced toads had little effect on the cane beetle, but they killed or ate just about everything else they came near.

Naturally, ever since then, Australians have tried to find ways to rid themselves of these self-introduced pests, which kill pets, swarm over the landscape in such numbers they look like a moving, toady carpet, and outcompete many Australian natives for food–or, they just eat them.

Cat food lures meat-eating ants

Recent news from Australia was that cane toad hunters might no longer be able to humanely dispatch the amphibians using carbon dioxide gas. Instead, the advice was going to be that bashing them over the head with a single, toad-dispatching blow would be the best way to control them. Now, some Australians have discovered another way to end a toad’s life: Death by meat-eating ant.

Evidently, the ant does not find the toad naturally attractive, but a spoon of cat food near areas where baby toads emerge from ponds brings the ants by the horde. The horde then finds a lot of tasty toads to eat, and…they eat them. Sounds painful, but evidently, it’s pretty effective, and no human has to bash a toad on the head.

The Australian researcher who made the cat food breakthrough is Rick Shine, a noted herpetologist whose recent research on behalf of native herps turned up this low-tech solution to the problem.

Ideas for thinkin’

Introducing the cane toads ended disastrously for Australia. Find other examples of introduced species. Why is it that populations of introduced species seem so easily able to explode in number? Think about concepts of co-evolution and species interactions.

In Austin, Tex., an invasive plant species, Hydrilla, has choked lakes and water treatment plants. Authorities are trying to control Hydrilla by introducing triploid Asian grass carp, another non-native species. What are the grass carp expected to achieve? Why? Why are they triploid? Can you think of benefits of this second introduction? What are some potential drawbacks, and what might be the first sign that they’re in progress? And where did that Hydrilla come from, anyway?

%d bloggers like this: