Tag Archives: birds

Scared of spiders? A world without them is true nightmare tale: Study

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The objects of revulsion, disgust and fear are frequently members of the arachnid class–think spiders, scorpions and harvestmen (daddy long legs). However, they are essential towards the prosperity of the ecosystems.

Considering the plummeting global biodiversity, and some even refer to it as the insect apocalypse, two ecologists at the University of Massachusetts Amherst chose to see what is generally happening with insects and arachnids in the United States, only to find huge gaps in the data. Their study, which was recently published in PNAS, suggests that an imminent need to evaluate, preserve and appreciate insects and arachnids, which is a major support of planetary health.

The senior author of the paper is Laura Figueroa, an assistant professor of environmental conservation in the UMass Amherst, who writes that insects and arachnids are basic to human society. They are useful in the pollination and control of pests biologically; they may also be used as environmental indicators to monitor air and water quality, and have become so ingrained in various other cultures all over the world that we can think of Aragog in the Harry Potter books, as an example. Many humans are interested in popular charismatic animals on earth such as the lion and the panda which deserved the international conservation interest rightfully. Since insects and arachnids do not normally receive the same attention, we were interested in how they were doing.

To determine the health of our creepier crawlier neighbors, Figueroa and her graduate student, Wes Walsh, the lead author of the paper, compiled conservation assessments of the 99312 known insect and arachnids species in North America, north of Mexico.

Findings mind boggling

As Figueroa says, almost 90 percent of the species of insects and arachnids, or 88.5 percent to be exact, have none of the conservation status. “We do not even know how they are doing. Little is known concerning the conservation requirements of the majority of the insects and arachnids in North America.”

The small data available was skewed to aquatic species that are crucial to water quality surveillance (mayflies, stoneflies and caddisflies), and more popular insect fauna such as butterflies and dragonflies got a disproportionate portion of protection.

Even the arachnids are not enjoying conservation; most states do not even protect one species of the spider group. More information and security to the insects, yet arachnids as well, says Walsh.

Another finding made by the team was that states that were most dependent on extractive industries, e.g., mining, quarrying and oil and gas extraction, had lower chances to protect either insects or arachnids but those with more eco-centric views by the populace were protecting more species.

Comparatively, Figueroa refers to the conservation of birds, which has been much more successful in conservation and preservation of species. According to the research, it turns out that you will get the best conservation efforts when there is a broad and diverse coalition of people. In the example of the birds, they were the hunters, the bird watchers, the nonprofit organizations and many more constituencies that joined their hands in an effort to achieve a unified objective.

Insects and arachnids are not things to be feared, as Walsh ignores with a gorgeous spider tattoo on his arm. It is time to value them and recognize their ecological significance, and this should start with the gathering of more information and the recognition that they deserve conservation.

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Wolves kill, and ravens recall where: What is the scavenging strategy?

At-risk mountain vipers and iguanas, in rare company at key wildlife talks

 

 

Wolves kill, and ravens recall where: What is the scavenging strategy?

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The legend went that wolves were followed by ravens to fresh kills. Another scavenging strategy is of much interest, as demonstrated by a tracking study.

The raven is usually the first to be on the scene when the wolf pack is running down its prey. The ravens are already waiting in queue to grab hold of the scrap of meat that is an oddity and may arise even before the predators have time to dig. The scavengers are so fast in getting to wolf kills that it is uncanny to people how they got there and the answer is that wolves must have ravens trailing on them.

However, a recent study that followed ravens and wolves in the Yellowstone National Park during two-and-a-half years reveals that the predators adopt a much more advanced approach. Ravens know the locations that wolves will most likely kill and they will fly far back to the location. According to the first author of the study, Matthias Loretto, “they are capable of flying six hours without making a landing, directly to a kill site.”

The findings were published in the journal of science, with suggestions that ravens attempt to locate food scattered in the landscape by the use of spatial memory and navigation. According to Loretto, ravens can travel long distances by flying, and apparently they have a good memory so they do not have to always keep up with wolves in order to make out of the predators.

The research was conducted by the Research Institute of Wildlife Ecology of the University of Veterinary Medicine Vienna and the Max Planck Institute of Animal Behavior (Germany) along with several other institutes across the world including the Yellowstone National Park (USA).

Putting a legend to the test

The research was conducted regarding the Yellowstone National Park where wolves were introduced in the mid 90s after 70 years. The wolves of the park are monitored using tracking collars which are implanted on a quarter of the wolf population in any given year, according to Dan Stahler, a Yellowstone biologist, who has been tracking the wolves of the park since its reintroduction, the ravens seem to prefer the company of the wolves: you find them flying directly overhead or even leaping behind them when they take down prey.

To the ravens, it is a lucrative foraging measure, because the wolves always generate food which the birds can deal with. “The rule of the birds, which we all had supposed, was,” says Stahler, “simply to keep near the wolves.” However, the assumption was not checked. He says he did not know what ravens could do because nobody had ever put them in the middle; nobody had ever put the scavenger into the perspective.

To get a full view of the behavior of the raven, the group fitted the birds with small GPS positioning devices, 69 ravens in all, which is, according to Loretto, simply insane. “The reason is that ravens are so watchful of the scene that they do not easily fall into traps,” he says. Researchers were keen to adjust the traps to the environment in order to trap the birds to tag them. To illustrate, traps placed near the campsites had to be covered with rubbish and fast-food lure, otherwise, the ravens would know that something was not right and would not approach it, according to Loretto who is now a scientist at the University of Veterinary Medicine Vienna.

Besides the tracking ravens, the researchers added the movement data of 20 Yellowstone collared wolves. They followed the animals through the winter when ravens most frequently occur with wolves and recorded GPS positions with intervals up to 30 minutes in the case of ravens and up to one hour in the case of wolves. They also added information as where and when wolves killed their prey which consisted mainly of elk, bison and deer.

The memory of lucrative sceneries

In more than two-and-a-half years of observation, scientists discovered only one unambiguous incidence of a raven trailing a wolf at a distance of over one kilometer or over an hour. “In the beginning we were confused,” says Loretto. “After we discovered that wolves were not being followed by ravens from a great distance, we could not understand why the birds came so fast to wolf killings.”

The pattern was obvious after the thorough analysis of the movement data. Instead of following predators at long distances, the ravens returned to certain locations where they could find wolf kills. Others covered as little as 155 kilometers per day, but in a highly directional way, towards locations where a carcass was likely to be found–although the time a kill will occur is indeterminate.

In regard to location, wolves kills are clumped into specific terrain features, which the wolves hunt more effectively, flat valley bottoms. Ravens were also much more likely to visit frequently wolfridden locations as compared to infrequently wolfrided locations, indicating that they learn and retain the long-term resource landscape that wolves cause.

Loretto says that ravens have already been known to recollect consistent food sources, such as landfills. “What did we find surprising is that they also appear to learn where the wolf killings are more frequent. One kill is random, and with time certain areas of the terrain prove more fruitful than others, but ravens seem to take advantage of this pattern.”

Greater understanding of the intellect of animals

The authors do not eliminate the possibility that wolves continue to be followed by ravens on a short distance. To locate wolf kills in their area, ravens must be able to determine this by short-range signals, probably by watching the movements of the wolves or hearing them howl. However, on a bigger level, the order is quite obvious: memory then, cues then. Spatial memory and navigation enables ravens to make decisions regarding where to start searching, in the first place, sometimes tens or even hundreds of kilometers.

Senior author Prof John M. Marzluff of the University of Washington adds: “What is evident in our work is the fact that ravens are able to be quite flexible in the locations they choose to feed. They do not remain attached to a certain wolf pack. They have the opportunity to select between numerous foraging opportunities since they have a good sense and recollection of the previous feeding places far and wide. This alters our way of thinking about scavenger finding food, and the notion may be that we have long underestimated certain ones.”

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Pythons are true choke artists; Take on prey as large as a deer

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Burmese pythons are not just big snakes, growing to more than 18 feet and 200 pounds, but big eaters, taking on prey as large as a deer.

Biologists at the University of Cincinnati found that it’s not just the size of its head and body that puts almost everything on a python’s menu. They evolved super-stretchy skin between their lower jaws that allows them to consume prey up to six times larger than similar-sized snakes.

Since most snakes swallow prey whole, they must have wide mouths to accommodate a meal. Unlike our lower jawbone, the lower jawbones of snakes are not connected, allowing them to open wide.

“The stretchy skin between left and right lower jaws is radically different in pythons. Just over 40% of their total gape area on average is from stretchy skin,” lead author and UC biology professor Bruce Jayne said. “Even after you correct for their large heads, their gape is enormous.”

Ecologists with the Conservancy of Southwest Florida capture a 215-pound Burmese python in Everglades National Park./Photo:Ian Bartoszek/Conservancy of Southwest Florida

Pythons are constrictors. They bite their prey and wrap their powerful coils around it, fatally cutting off the animal’s vital blood flow, before consuming it whole at their leisure.

The bigger the prey, the more energy a snake derives from a meal. For pythons, that means not having to hunt as often, which can carry extensive risk in a world full of busy roads and dangerous predators.

Along with pythons, Jayne studied the gape size of brown tree snakes, a mildly venomous arboreal specialist that hunts birds and other animals in the forest canopy. Brown tree snakes were introduced in the 1950s to Guam, wiping out many bird species.

Besides measuring the snakes, Jayne also measured the dimensions and weight of potential prey animals. This allowed Jayne to use snake size to predict the maximal size of its prey and the relative benefits of consuming different types such as alligators, chickens, rats or deer.

Small snakes derive greater benefits in relative prey mass from a modest increase in gape size, the study found. This gives python babies an early advantage in taking on a broader range of prey compared to other snakes their size, Jayne said.

Being big also helps snakes avoid becoming meals themselves. Snakes fall prey to everything from wading birds to minks and raccoons to alligators and other snakes.

“Once those pythons get to a reasonable size, it’s pretty much just alligators that can eat them,” Jayne said. “And pythons eat alligators.”

Like invasive brown tree snakes in Guam, Burmese pythons are wreaking havoc on the ecology of Everglades National Park where they were introduced due to the release of captive animals from the exotic pet trade in the 1980s.

Study co-author Ian Bartoszek works as an environmental science project manager for the Conservancy of Southwest Florida, where he has led a project to track pythons. They implant radio transmitters in male snakes during breeding season to find females before they can lay more clutches of eggs. A big female python can lay more than 100 eggs.

Researchers routinely find deer hooves and the remains of other big animals in their stomachs. Bartoszek photographed one python regurgitating a full-grown white-tailed deer.

“The Everglades ecosystem is changing in real time based on one species, the Burmese python,” Bartoszek said.

The good news is that pythons rarely attack people. Bartoszek said the only defensive encounters he’s had with wild pythons are with females guarding their nests.

“It’s way more dangerous to drive there than to work with the snakes,” he said.

How songbirds’ striking, unique colors put them at risk [Details]

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Bright, uniquely colored songbirds are at higher risk of extinction and more likely to be traded as pets, according to researchers reporting in Current Biology on September 15. The researchers also predict that almost 500 additional bird species, most of them living in the tropics, are at risk of future trade based on their unique and desirable coloration.

“Aesthetic value is an important part of how people value nature,” said Rebecca Senior (@RebeccaASenior) of Durham University, U.K. “However, there is potential for conflict when what motivates some people to protect certain species is the same thing that makes other people want to own them. Songbirds are highly sought after in the pet trade, particularly for their beautiful songs. However, songbirds can also be remarkably colorful—a highly desirable trait in other commonly traded species, such as parrots.”

In their new study, Senior and colleagues including Brett Scheffers (@BrettScheffers) of University of Florida, Gainesville explored the antagonistic roles of aesthetic value in biodiversity conservation. They used novel metrics of color to evaluate the aesthetics of groups of birds, across the world and the avian tree of life.

Common hill myna (Gracula-religiosa); Least Concern; color uniqueness score of 66.9/Rick Stanley and Gabby Salazar

Their analysis shows that the tropics are the epicenter of bird color, with 91% and 65% of the world’s most diverse and uniquely colored assemblages of songbirds, respectively. They report that the pet trade, which affects 30% of all bird species, targets clusters of related and uniquely colored birds. They went on to identify 478 species of birds that may be at risk of future trade based on their appealing colors.

“We were surprised to see the strength of the latitudinal gradient in color; even when you account for the greater number of species in the tropics, the diversity of color in the tropics dwarfs all other regions,” Senior said.

While one might expect brilliant blues, oranges, and yellows to put species at risk, the researchers were also surprised to discover that pure white is a unique color found in many sought-after species, such as the endangered Bali myna. The findings overall highlight that the same color features that make some people willing to travel around the world for a mere glimpse of a bird through binoculars also potentially puts them at risk for pet trading. The findings have important implications for conservation.

Kuno national park

“Understanding what motivates trade is essential to identify at-risk species potentially requiring more proactive protection from trapping,” Senior said. “Trade has the capacity to be regulated and managed sustainably with a better understanding of what is traded as well as where and why trade occurs. Loss of colorful species also directly erodes aesthetic value, which is problematic because, for better or worse, it is this value that often fundamentally motivates and funds conservation efforts.”

In future studies, they hope to disentangle even more factors that play into regional variation in patterns of trade among birds. They’d also like to explore the role of color in the trade of other groups of animals and plants.

Scientists fix GPS device to pelican’s wings in Karnataka’s Mandya district

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Mandya (Karnataka), Sep 12 (IANS) Scientists on Monday successfully fitted a GPS device to a pelican bird in Kokkare Bellur in Karnataka’s Mandya district.

A team of scientists attached to the Dehradun Wildlife Institute carried out the experiment for the first time in the country, according to the local officials.

The experiment was carried out to study the abodes of pelicans, food habits and international routes that these migratory birds traverse.

Sources said that the GPS device was imported from Greece. The animal lovers and scientists have described the experiment as historical.

Spot-billed pelican birds

The GPS device will help ascertain the route, including countries the pelican’s travel through besides recording their activities. The scientists have also stated that they would be able to find out the origin place of the bird through this experiment.

Pelican birds travel across India, Sri Lanka and Myanmar. The GPS device will get charged automatically through sun rays. The device is designed to send all the information regarding various travelling routes for a period of four years.

Attractive pelican birds arrive in Kokkare Bellur in October and disappear after two months. This breed of birds are found in Karnataka, Tamil Nadu, Sri Lanka, Malaysia and Myanmar.

Giraffes, parrots, oak trees, cacti among many species facing extinction

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It may be surprising to learn that even giraffes, parrots, and oak trees are included in the list of threatened species, as well as cacti and seaweed.

Seaweed is one of the planet’s great survivors, and relatives of some modern-day seaweed can be traced back some 1.6 billion years. Seaweed plays a vital role in marine ecosystems, providing habitats and food for marine lifeforms, while large varieties – such as kelp – act as underwater nurseries for fish.

However, mechanical dredging, rising sea temperatures and the building of coastal infrastructure are contributing to the decline of the species.

The world’s trees are threatened by various sources, including logging, deforestation for industry and agriculture, firewood for heating and cooking, and climate-related threats such as wildfires.

Unsplash/Shane Stagner.
Kelp, a type of seaweed, can be fed to animals and could help to reduce greenhouse gas emissions.

It has been estimated that 31 per cent of the world’s 430 types of oak are threatened with extinction, according to the International Union for Conservation of Nature (IUCN) Red List of threatened species. And 41 per cent are of “conservation concern”, mainly due to deforestation for agriculture and fuel for cooking.

Giraffes are targeted for their meat, and suffer from the degradation of their habitat due to unsustainable wood harvesting, and increased demand for agricultural land; it’s estimated there are only around 600 West African giraffes left in the wild.

Dino-killing asteroid’s impact on bird evolution

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Human activities could change the pace of evolution, similar to what occurred 66 million years ago when a giant asteroid wiped out the dinosaurs, leaving modern birds as their only descendants. That’s one conclusion drawn by the authors of a new study published in Systematic Biology.

Cornell University Ph.D. candidate Jacob Berv and University of Bath Prize Fellow Daniel Field suggest that the meteor-induced mass extinction (a.k.a. the K-Pg event) led to an acceleration in the rate of genetic evolution among its avian survivors. These survivors may have been much smaller than their pre-extinction relatives.

“There is good evidence that size reductions after mass extinctions may have occurred in many groups of organisms,” says Berv. “All of the new evidence we have reviewed is also consistent with a Lilliput Effect affecting birds across the K-Pg mass extinction.” Paleontologists have dubbed this phenomenon the “Lilliput Effect” — a nod to the classic tale Gulliver’s Travels.

“Smaller birds tend to have faster metabolic rates and shorter generation times,” Field explains. “Our hypothesis is that these important biological characters, which affect the rate of DNA evolution, may have been influenced by the K-Pg event.”

The researchers jumped into this line of inquiry because of the long-running “rocks and clocks” debate. Different studies often report substantial discrepancies between age estimates for groups of organisms implied by the fossil record and estimates generated by molecular clocks. Molecular clocks use the rate at which DNA sequences change to estimate how long ago new species arose, assuming a relatively steady rate of genetic evolution. But if the K-Pg extinction caused avian molecular clocks to temporarily speed up, Berv and Field say this could explain at least some of the mismatch. “Size reductions across the K-Pg extinction would be predicted to do exactly that,” says Berv.

“The bottom line is that, by speeding up avian genetic evolution, the K-Pg mass extinction may have temporarily altered the rate of the avian molecular clock,” says Field. “Similar processes may have influenced the evolution of many groups across this extinction event, like plants, mammals, and other forms of life.”

The authors suggest that human activity may even be driving a similar Lilliput-like pattern in the modern world, as more and more large animals go extinct because of hunting, habitat destruction, and climate change.

“Right now, the planet’s large animals are being decimated–the big cats, elephants, rhinos, and whales,” notes Berv. “We need to start thinking about conservation not just in terms of functional biodiversity loss, but about how our actions will affect the future of evolution itself.”