Barn owl defends her young against snake


This video from the USA says about itself:

Barn Owl Attacks Snake Entering Nest Box. May 6, 2015

Watch this incredible footage of Dottie the female Texas Barn Owl defending her young against a Texas Rat Snake that attempted to enter the nest box.

From the Cornell Lab of Ornithology in the USA about this:

Earlier this month, we witnessed a reminder that the Texas Barn Owls aren’t the only ones hunting for food during the night. Despite extensive predator guards installed around the owls’ box, a Texas rat snake gained access to the rafters. Our cameras captured the ensuing showdown as the snake approached the nest box entrance. Despite the midnight darkness, Dottie (the female owl) evicted the snake from the box, then, moments later, gathered her nestlings back to safety beneath her. Watch video [above].

It’s not just other predators that make raising a family of Barn Owls tough. The breeding ecology of Barn Owls can be boom-or-bust. They can be prolific breeders, often laying six or more eggs during a single breeding attempt, but if there’s not enough prey to support all of the nestlings, many can perish. One 16-year study in Utah found that, on average, only 63 percent of eggs hatched and 87 percent of hatchlings survived to fledging. This year, only 5 of 6 eggs hatched in the Texas Barn Owl nest and the youngest owlet (hatched nearly 11 days after the oldest) did not survive. The four remaining owlets appear healthy and well, and we are hopeful that they will survive to fledge. Watch cam.

Galapagos tortoises freed on island where they had become extinct


This video is called World’s BIGGEST TORTOISE! The Giant Galapagos Tortoise, 5 fascinating facts.

From daijyworld.com:

207 giant turtles to be released in the Galapagos

Quito (Ecuador), May 23 (IANS): Administrators at Ecuador’s Galapagos National Park said 207 giant turtles will be released next month on the island of Santa Fe, where the native tortoises died out more than 150 years ago.

The turtles to be set loose on June 5 by the park directors and the Galapagos Conservancy group belong to the species Chelonoidis hoodensis, Spanish news agency Efe reported from the South American nation.

Native to the Galapagos island of Espanola, the Chelonoidis [hoodensis] is morphologically and genetically similar to the original Santa Fe turtle.

The aim of the initiative is to establish “a breeding population that fulfills a function in the ecosystem”, park management said.

“Once the turtles are introduced, a key part of this project is to assess changes in the ecosystem resulting from the presence of these chelonians, and to evaluate the interaction between the turtles and the island’s land iguanas, particularly in the use of shared resources like food,” Danny Rueda, Galapagos ecosystems director, said.

The turtles to be released on Santa Fe range in age from four to 10 and have been raised in captivity.

Around 40 of the turtles will be equipped with a GPS device that will relay data on their movements and activities.

Pirates and whalers depleted the population of turtles in the archipalago, leaving only 15 individuals that allowed park management and the Charles Darwin Foundation to start a breeding programme.

The eradication in 1971 of the goats that had been introduced to the islands contributed greatly to the recovery of the ecosystem.

The Galapagos Islands, located about 1,000 km west of the coast of continental Ecuador, were declared a World Natural Heritage Site in 1978.

Giant tortoises, new research


This video is about giant tortoises and turtles.

From the BBC:

The truth about giant tortoises

They’re big but tortoises used to be much bigger, and while they may be slow on their feet their minds may be surprisingly quick

Henry Nicholls

Reputation: Giant tortoises live on islands. They can be aged by studying growth rings on their shells, which is how we know they are the longest lived vertebrate on record. Charles Darwin found they moved a whole lot faster than he’d imagined.

Reality: Giant tortoises are a recent evolutionary innovation and used to be everywhere, not just on islands. It’s impossible to age them accurately unless you know when they hatched. They are actually pretty slow. Darwin was probably chasing them.

The largest tortoises in the world are to be found on the Seychelles in the Indian Ocean and in the Galápagos in the Pacific. But this truth has given rise to the false belief – often found in textbooks – that their large size is a product of island life. It almost certainly isn’t.

This much is evident from a cursory inspection of the fossil record. A typical Galápagos tortoise has a carapace around 100 cm long. If this is the benchmark for “giant”, it is clear that giant tortoises were not restricted to small islands. They were everywhere.

In the southern USA and Central America, for instance, there was a monster of a tortoise known as the southeastern giant tortoise (Hesperotestudo crassiscutata) that only went extinct around 12,000 years ago.

In Queensland, Australia there used to be a beast that goes by the name of Owen’s giant horned ninja turtle (Ninjemys oweni). Before you ask, yes, it was named after the ninja turtles of teenage mutant fame.

Then there was the real mother of all giants, the Siwaliks giant tortoise (Megalochelys atlas), which was tramping around what is now the Punjab in India until a few million years ago. It was around twice the size of a Galápagos tortoise.

In addition, a 1999 genetic analysis of Galápagos tortoises suggests their ancestors were probably pretty large before they left mainland South America several million years ago.

In fact, it’s been argued that being big was a necessary pre-adaption for the successful colonization of remote oceanic islands. If it finds itself in the water, a giant tortoise will bob along tolerably well, its long neck ensuring it doesn’t take on too much water.

If there used to be so many giant tortoises, where are they all now? A recent study by the International Union for Conservation of Nature indicates that giant tortoises have suffered a far higher incidence of extinction than more modestly sized tortoises and turtles.

“These slow moving and non-threatening animals required minimal effort to find,” wrote Anders Rhodin, director of the Chelonian Research Foundation and his colleagues.

Worse, giant tortoises can survive without food or water for long periods. That meant they could be stored – alive – to provide fresh meat many months down the line.

“Tortoises were, essentially, the earliest pre-industrial version of ‘canned food’,” they suggest. Early hominins opened their shells with stone-tool “can-openers”.

It is only because humans came late to the Seychelles and the Galápagos that we can still marvel at these creatures today.

In these isolated spots, giant tortoises have become reptilian representatives, their extreme longevity casting them as a living link to a lost world. But how long do they live, really?

It is often said that you can age a tortoise by counting growth rings on its shell. Unfortunately, this is only reliable for the first year or two and is useless for aging an animal that is fully grown – which for giant tortoises is at the age of around 20.

The only reliable method of aging a tortoise is to record its year of birth. In a few instances where this has been done for giant tortoises, it is clear they can live for 150 years or more.

Giant tortoises are not known for their speed. When in the Galápagos in 1835, Charles Darwin found that they moved faster than he’d imagined.

“One large one, I found by pacing, walked at the rate of 60 yards in 10 minutes, or 360 in the hour,” he wrote in his Zoology Notes. “At this pace, the animal would go four miles [6.4 km] in the day & have a short time to rest.”

More recently, researchers have been using tracking devices to record movements of Galápagos tortoises in more detail. It turns out they are not nearly so lively, most of the time making small movements around a relatively small patch.

“Our tortoises don’t usually move more than absolute max of 2 km per day,” says Stephen Blake, coordinator of the Galápagos Tortoise Movement Ecology Programme. “Darwin was probably chasing them.”

They might be slow, but they are also probably smarter than most people imagine.

Research on the South American red-footed tortoise (a not-too-distant relative of the giant tortoises in the Galápagos) shows they use landmarks to create cognitive maps of their surroundings. They can also follow the gaze of another tortoise and learn from the behaviour of others. It seems likely that giant tortoises are capable of similar cognitive feats.

Cuckoo, Canada geese and little grebe


This video is called The European Adder – Vipera berus. We did not see adders during our week in and around Dwingelderveld national park. They live there; but the best time to see them is on warm, sunny days. Which weren’t part of this early May week.

After 6 May 2015, 7 May in Drenthe. Our last full day there.

As we went to the hide, a robin on a fence.

Near the hide, swifts and barn swallows flying. A willow warbler sings.

In a lakelet just north of Moddergat lake, three common pochards, male and female tufted ducks.

A little grebe calls and swims.

A mallard. Two Egyptian geese: a Canada goose calls to them as they land.

In wet heathland, a skylark sings.

Cuckoo, 7 May 2015

A cuckoo sitting on a tree.

Briefly, a yellowhammer above the cuckoo in the same tree.

A stonechat.

Canada geese, 7 May 2015

Canada geese.

Next, another wetland: Koelevaartsveen. Three common sandpipers near the bank.

Moss and trees, 7 May 2015

Moss growing near the trees not far away.

Moss, 7 May 2015

Near the Dwingelose heide cycle track, again oak eggar caterpillars.

Dark tussock caterpillar, photo by Lo Troisfontaine

Also a much rarer and smaller caterpillar. So small and lightweight that the wind again and again blows it decimetres further away on the sandy path. A dark tussock caterpillar.

Cottongrass, 7 May 2015

Back to the hide. Cottongrass grows there. This marked the end for us of a week of seeing much beautiful wildlife.

Mating adders, video


This video shows mating adders, in Engbertsdijksvenen nature reserve in Overijssel province in the Netherlands.

G. Tjeerds made the video.

Cornell red-tailed hawks nest update


This video from the USA says about itself:

Red-Tailed Hawk vs. Rattler

In the scorching desert sky, a hawk spies prey — a venomous rattler! Who wins out in this battle of the predators?

From the Cornell Lab of Ornithology in the USA:

May 6, 2015

Two hatched out, one to go…

As thousands of viewers watched, the second egg hatched in the nest of Red-tailed Hawks Big Red and Ezra during the afternoon of May 5. Viewers were captivated as Ezra stood over the hatchling, tenderly removing excess material from the egg as the hatchling emerged (watch highlight).

Our first nestling, F1, has already received several meals over the last 48 hours (watch highlight). Now downy and fresh, F1 appears twice as large as the egg that contained it just a few days ago. The third egg should hatch in the next couple days—don’t miss the chance to see it happen live! Watch now.

Dinosaur with feathers and bat-like wings discovered


This video says about itself:

A new dinosaur: Flying without feathers

29 April 2015

Birds evolved from dinosaurs – but it wasn’t a smooth transition. Plenty of creatures tried different ways to get into the air – like this newly discovered dinosaur species, Yi qi, unearthed in China. This pigeon-sized creature had elongated fingers that held a membrane wing, more like a bat than a bird. In this Nature Video, we look at what makes this fossil so special, and consider what this dinosaur may have looked like.

From daily The Guardian in Britain:

Is it a bird? Is it a bat? Meet Yi qi, the dinosaur that is sort of both

Incredible new find from China has both feathers and bat-like wings

Dr Dave Hone

Wednesday 29 April 2015 18.01 BST

Researchers today announced the discovery of a stunning new dinosaur fossil: a glider with wings similar to both birds and bats. It has been named Yi qi (meaning ‘strange wing’) and is a small feathered dinosaur from the Middle Jurassic age fossil beds of China that have yielded a host of important fossils in recent years. Yi qi, like so many other small dinosaurs, is preserved with a full coating of feathers and was a close relative of the lineage that ultimately gave rise to birds.

However, what sets this animal apart from numerous other dinosaurian gliders and proto-birds is the composition of its wings. In addition to some unusual feathers that are positioned on the long arms and fingers, there is a truly gigantic bone on each wrist that extends backwards, and between this bone and the fingers is preserved a membrane-like soft tissue that would have given the animal something of a wing, like that of bats.

Yi qi is not a direct ancestor of birds, and more particularly has nothing to do with the origins of the mammalian bats, but its wings are an excellent example of convergent evolution. At various times a great many animals have evolved a similar arrangement of a large bone in the wrist or hand and a supporting membrane, most obviously in numerous gliding mammal lineages. In addition to the bats that are capable of active powered flight, various passive gliders like flying squirrels, sugar gliders and the so-called “flying lemurs” have all independently evolved some extension that that helps to support a membranous wing. At some level then, this is a quite common feature, but it is a real shock to see it in such a dinosaur.

Professor Xu Xing, lead author of the study from the Institute of Vertebrate Paleontology and Paleoanthropology, Beijing said “It definitely evolved a wing that is unique in the context of the transition from dinosaurs to birds.”

There are a number of feathered dinosaurs close to the origins of birds that are thought to have been some form of glider. All were small and light and had extensive feathers that would have formed the flight surface and allowed them to move effectively through the air. Yi qi is from a very odd group of small dinosaurs called scansoriopterygids, who are known from only two other specimens and little is known about their biology or lifestyle, so there is not much to go on. However, it is clearly remarkable that such an animal that had numerous other relatives with large feathers on their arms and would apparently “experiment” with different forms of flight at various times (not least ultimately producing birds) would take such a dramatically different route towards gliding, even if it was one commonly explored by other [sic] mammals.

The evolutionary implications are therefore quite incredible. There have already been suggestions that perhaps powered flight evolved multiple times in the dinosaurs and early birds, with perhaps several different groups making the final jump from gliding to a more active form of movement in the air. Given how few and far between the scansoriopterygids are as fossils, this implies that they never really got going as a group – certainly they are much more restricted in both time and space than their near relatives, so at first approximation the bat-bird combination of Yi qi did not lead to a major new radiation of dinosaurs.

However, quite how the animal may have flown is most unclear. The incomplete preservation of the wings and the uncertain position of the long wrist bone means that it could have had a very broad wing or a narrow one, and the flattened nature of the skeleton makes it hard to tell if this animal might have had the muscles and joints needed for powered flight. Professor Xu notes that “We don’t know if Yi qi was flapping, or gliding, or both”, but it does seem clear that the small size of the animal and large surface area of the wings and feathers would have permitted some form of aerial locomotion.

Dr Mike Habib of the University of Southern California, who was not involved in the study, said “All told, this is an unexpected, exciting specimen that changes our views on the evolution of flight in dinosaurs. It appears that multiple types of wing surfaces evolved within the relatives of birds, making the origins of avian flight potentially more complicated than previously thought.” That alone makes the origins of birds, already an area of intense study, a little more complicated and rather intriguing. The pathway to both birds and powered flight from small feathered dinosaurs, though with a few bumps and oddities on the way shows a relatively consistent progression but Yi qi adds a new twist with one evolutionary branch taking a dramatically different route into the air.

Xu et al., 2015. A bizarre Jurassic maniraptoran theropod with preserved evidence of membranous wings. Nature. DOI: 10.1038