Tag Archives: animals

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.”

Read More:

‘Plenty of fish in the sea’? Not anymore, say UN experts in Nice

Sound reveals ‘Ocean giants’ dance with wind to find food

 

Upset over barking, man shot dead dog in Karnataka village

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Sep 18 (IANS) In a shocking case, a man shot dead a dog for barking at him in Bengaluru’s Madagondanahalli on Sunday.

The Karnataka Police filed a case against the man.

According to police, the person who shot the dog has been identified as Krishnappa, a local resident. Krishnappa was irked over the barking of the dog, named Rocky, at him and shot it in the head with an air gun.

Dog/Ians

Police said that Krishnappa had chased the dog for quite a distance before shooting at it in the village. The villagers were shocked to see the dog being killed in a public place.

The dog was nursed by Harish who also belonged to the same village. He lodged the complaint with Doddaballapura rural police station.

Animal lovers have expressed shock over the incident.

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.

ZimParks relocates 100 elephants, 70 giraffes, 10 lions due to drought

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Harare, Sep 15 (IANS) Amid an ongoing drought, the Zimbabwe National Parks and Wildlife Management Authority (ZimParks) said it has relocated 100 elephants since July and a significant number of other wild animals from the arid southern parts of the country to the north where there is better vegetation and water.

ZimParks spokesperson Tinashe Farawo told Xinhua news agency on Wednesday that the Authority issued permits for the transfer of 2,650 animals from the Save Valley Conservancy to three national parks in the north namely Tsapi, Chizarira and Matusadonha.

The animals targeted for relocation include 400 elephants, 2,000 impalas, 70 giraffes, 50 zebras, 50 buffaloes, 50 elands, 10 lions and 10 wild dogs.

The relocation exercise began in July and so far, 100 elephants and a “significant number of other wild animals” had been relocated, he said.

He said the main reason for relocation was to depopulate overcrowded areas and create a balance in the ecosystem.

Climate change induced-drought resulting in loss of habitat, food, and water was posing a risk to the animals and the only way to protect the habitat was to make sure that we create a balance by relieving pressure on overcrowded areas, Farawo said.

Zimbabwe has become prone to frequent droughts in recent years due to climate change, posing the risk of hunger not only to humans but also to wild animals.

The country has an overpopulation of elephants numbering over 100,000 against an ecological carrying capacity of 45,000.

The jumbos are located in four main ecological zones, and two of the zones are overpopulated.

An elephant herd is spotted near nyamandhlovu pan, a popular water-hole in the Hwange National Park, Matabeleland North Province, Zimbabwe

The four zones are North West Matabeleland where the country’s biggest game park Hwange is located; South East Lowveld, home to the second biggest park Gonarezhou; as well as the Sebungwe region and mid Zambezi in the northern part of the country.

This is not the first time that ZimParks has moved the animals.

Lions

In 2018, it moved 100 elephants from the South East Lowveld to mid Zambezi while plans to relocate 600 elephants in 2020 were affected by the Covid-19 pandemic.

The relocation program is an expensive exercise and ZimParks has in the past lamented inadequate funds to successfully carry out the program.

Ministry of Environment, Forest and Climate Change organises National Conference on Sustainable Coastal Management

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Union Minister of Environment, Forest and Climate Change, Shri Bhupender Yadav inaugurated the first National Conference on Sustainable Coastal Management in India in Bhubaneswar today.

This conference is being organized by the Green Climate Fund supported project – Enhancing Climate Resilience of India’s Coastal Communities.

The objective of the conference is to bring officials from all 13 coastal states of India under one roof to focus on the three interrelated themes :

  1. Coastal and marine biodiversity,
  2. Climate mitigation and adaptation and
  3. Coastal pollution.

This endeavour is aimed at creating a vibrant network of stakeholders who will continue to engage with each other on the topics but also on cross-cutting themes such as coastal governance, technologies and innovation as well as domestic and international finance.

“The Indian coastline is of immense strategic, economic and social importance to the country.

  • Indian coastline spans 7,500 kilometres, seventh longest in the world,
  • home to 20 percent of the country’s population,
  • Three of our four metropolitan cities lie on the coast,
  • supports more than 17,000 species of plants and animals.

There is a great diversity of ecosystems within our coastal regions that support more than 17,000 species of plants and animals.  With the changing climate, we need to build the resilience of communities living in coastal areas.” said Shri Bhupender Yadav, Union Minister of Environment, Forest and Climate Change.

Sustainable Coastal Management in India

“This conference comes at an important time as India has submitted its revised NDCs and seeks to create multi-sectoral partnerships to meet these targets” he added.

Speaking on the occasion, Shri. Ashwini Kumar Choubey, Minister of State for Environment, Forest & Climate Change, said: “Such conferences are important to bring the conversations of resilience and sustainability to our country’s coastal areas.  This was also envisioned in the Honourable Prime Minister’s LiFE movement.”

Sustainable Coastal Management in India

Sustainable coastal management is recognised as need of the hour. Data-driven policies and management frameworks, participatory conservation models, and convergence between stakeholders are the key pillars for effective coastal management.

A programme on Enhancing Climate Resilience of Coastal Communities is being implemented in partnership with UNDP in the states of Odisha, Andhra Pradesh and Tamil Nadu. Supported by the Green Climate Fund (GCF), the initiative is integrating ecosystem and community-based approaches to adaptation into coastal management and planning.

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.

Scientists take a deep dive into how ‘elasmobranchs’ use the ocean depth

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Using sophisticated electronic tags, scientists have assembled a large biologging dataset to garner comparative insights on how sharks, rays, and skates – also known as “elasmobranchs” – use the ocean depths. While some species spend their entire lives in shallow waters close to our shores on the continental shelf, others plunge hundreds of meters or more off the slope waters into the twilight zone, beyond where sunlight penetrates. This new understanding of how elasmobranchs use the ocean will enable policymakers and resource managers the opportunity to examine the threats these animals face, and guide future management and conservation plans.

A study published Aug. 19 in Science Advances, led by Stanford University and ZSL (Zoological Society of London) researchers, is the largest global investigation of where and when a diverse group of elasmobranchs move vertically. A team of 171 researchers from 135 institutions across 25 countries brought together two decades of data from satellite and archival tags that remotely tracked the movements and behaviors of 38 species in oceans across the globe.

“For the first time, we have a standardized, global database that we used to fill important knowledge gaps about the diving behaviors of sharks and rays,” said Samantha Andrzejaczek, co-lead author of the study and a postdoctoral research fellow at the Hopkins Marine Station of Stanford University. “This will enable better understanding of what fisheries interact with elasmobranchs and how to improve management of many of these long-lived animals.”