Fossil Reshuffles Avian Family Tree

Reconstruction of Aurornis xui MASATO HATTORI

Reconstruction of Aurornis xui
MASATO HATTORI

A newly discovered fossil of what may be the earliest known bird redraws the picture of the early avian evolution, but some researchers are not convinced.

Researchers have found a fossil that they claim is the earliest known bird species, a discovery that has scientists rethinking the ever-changing evolutionary tree of early birds and non-avian feathered dinosaurs. The specimen, a chicken-sized creature named Aurornis Xui that lived roughly 150-million-years ago, was described in a study published this week  in Nature.

“If Aurornis is the most primitive bird, then it is a huge discovery,” paleontologist Stephen Brusatte the University of Edinburgh in the U.K., told the Not Exactly Rocket Science blog, written by Ed Yong, a regular contributor to The Scientist. But the analysis of the specimen and its place in the evolutionary tree is up for discussion, and Brusatte is “not convinced that this paper resolves the early history of birds.”

Dozens of species of feathered dinosaurs have been unearthed over the past decade or so, many of them from Liaoning province in northeastern China, but which of these represented the first birds has been a controversial question. It was thought that Archaeopteryx, a creature with feathered wings that looked capable of flight from roughly the same period as the new fossil, was the earliest bird. But in 2011, Xing Xu of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing argued that Archaeopteryx was actually a non-avian feathered dinosaur, like Velociraptor. That meant flapping flight must have evolved twice: once in the group of which Archaeopteryx is now a part, and again in the lineage that led to modern birds.

Now, with the discovery of Aurornis, a team led by Pascale Godefroit of the Royal Belgian Institute of Natural Sciences in Brussels, Belgium, has redrawn the evolutionary tree once again. The researchers compared 1,000 skeletal features of Aurornis with those of 101 other dinosaurs and birds, and concluded that the new specimen is a distinct species. Moreover, their analysis restored Archaeopteryx to its perch on the bird branch of the evolutionary tree, suggesting that flight need only have evolved once, and placed Aurornis just below Archaeopteryx as the earliest known bird.

But Brusatte told ScienceNOW that some of the specimens viewed as distinct species might be juvenile and adult versions of the same species, and added that the team’s new evolutionary tree is just one of several possible interpretations.

source:the-scientist.com

Number of puffins remains the same despite weather

The number of puffins in the North Sea has stayed the same despite the death of thousands of birds due to severe weather at the start of spring.

In March around 3,500 puffins, including breeding adults, were found dead along the coast of eastern Scotland and north-east England.

The puffin population of the North Sea coast has remained constant despite the death of thousands of the birds Credit: Anna Gowthorpe/PA Wire

The puffin population of the North Sea coast has remained constant despite the death of thousands of the birds Credit: Anna Gowthorpe/PA Wire

But a count of the birds, funded by Scottish Natural Heritage (SNH), found that their numbers were similar to levels recorded in 2009.

The Isle of May National Nature Reserve, on the edge of the Firth of Forth is home to the largest colony of puffins in the North Sea area and is a UK hub of research into puffins.

Researcher Mike Harris, from the Centre for Ecology & Hydrology, said: “This March’s wreck has clearly had a serious effect on the puffins on the Isle of May but, perhaps surprisingly, numbers are very similar to the last count which took place in 2009.

“Our general impression over the last few years was that the population was increasing slowly and this may explain why we have not seen a decline following the recent wreck.”

source: itv.com

Brazil rainforest deforestation leads to seed shrinkage

Scientists think the loss of large fruit-eating birds, such as the toucan, is causing seeds to shrink

Scientists think the loss of large fruit-eating birds, such as the toucan, is causing seeds to shrink

The destruction of tropical rainforests is having an even greater impact on the environment than was previously thought, a study suggests.

Scientists have found that deforestation in Brazil is causing trees to produce smaller, weaker seeds that are less likely to regenerate.

They believe this has been triggered by the loss of large birds from the forests, which have beaks big enough to feed on and disperse the seeds.

The study is published in Science.

Pedro Jordano, from the Donana Biological Station in Seville, Spain, said: “One of our major surprises was how rapidly deforestation could not only be influencing the disappearance of the fauna, but to observe how deforestation could influence the evolution of the plant traits so rapidly – within a few generations.”

Tiny beaks

The researchers found the seeds from fragmented patches of forests were significantly smaller

The researchers found the seeds from fragmented patches of forests were significantly smaller

Brazil’s Atlantic rainforest was once home to a vibrant array of plants and animals.

But with the arrival of sugar and coffee plantations in the early part of the 19th Century, it was rapidly destroyed.

Today, just 12% of the original forest remains.

To assess the impact, researchers looked at more than 9,000 seeds collected from palm trees throughout the rainforest.

Those taken from areas that had suffered heavy destruction were much smaller than seeds collected in undisturbed patches of forest.

The researchers considered a wide array of factors that might have led to the shrinkage, such as the climate, soil fertility and forest cover.

“But we found no evidence for any of those effects,” explained Prof Jordano, who carried out the research with Sao Paulo State University, in Brazil.

“The main factor was the disappearance of the large frugivore (fruit-eating) species.”

Usually, species such as the toucan and cotinga use their large beaks to eat the fruit, eventually spreading the seeds throughout the forest.

But as the rainforest was flattened, these birds vanished, leaving smaller birds behind such as the thrush.

The smaller seeds are better suited to little birds, such as the yellow-legged thrush, but they are weaker and less likely to germinate

The smaller seeds are better suited to little birds, such as the yellow-legged thrush, but they are weaker and less likely to germinate

By evolving to produce smaller fruits, which birds with tinier beaks could handle, they were more likely to be dispersed.

However the researchers found these seeds were weaker.

“Unfortunately the smaller seed size also means a lower probability for successful recruitment in the forest,” said Prof Jordano.

“Smaller seeds are less likely to germinate, they are prone to losses by desiccation and they are more quickly attacked by fungi.”

He added that projected climate change could render rainforests drier and hotter, making the survival of the seeds even less likely.

The researchers said their findings were probably not limited to the Atlantic rainforest.

Prof Jordano said: “Really the story we are documenting can also be happening for many other tree species.

“Unfortunately it will also be common in other tropical areas around the world, where the large toucans, the tapirs, monkeys and other big mammals and birds are disappearing very quickly from the forest.”

source: bbc.co.uk

Bees teach birds lesson about nesting

A dead bumblebee attached to a speaker used to create a buzzing sound was enough to make a tit abandon its nest box and eggs.

A dead bumblebee attached to a speaker used to create a buzzing sound was enough to make a tit abandon its nest box and eggs.

If you think you know all about the birds and the bees, think again.

Bumblebees can intimidate birds into abandoning their nests and even to abandoning their eggs, researchers in South Korea have shown.

The experiments, conducted by Seoul National University’s laboratory of behavioural ecology and evolution, studied the interactions between bees and Oriental and Varied tits on the slopes of the Gwanak mountain. They found the bees’ warning buzz, coupled with their conspicuous colouring, enabled the diminutive insects to steal the freshly built nests from their much larger predators. The study observed bumblebees present in more than a fifth of the nest boxes they recorded.

The birds, natural hunters of the bees, were found to be significantly distressed if they came upon a bumblebee in their freshly built nest boxes.

Bumblebees are known to require cavities for nesting, and can use abandoned nests of other animals. However, bumblebees invading freshly built nests are a relatively modern finding, the scientists said.

The research, lead by Piotr Jablonski, showed that when a small speaker emitting a bee buzzing noise was placed in the tits’ nest, alongside a dead bumblebee glued to an upright toothpick, the birds often abandoned their nests.

These findings are novel as there has been very little research done on understanding this type of competition between prey and predator, the authors write. They believe it is possible that “the warning auditory signals not only help bumblebees in competition with their avian predators but also in competition for cavities with [a] variety of other animals”.

The research is published online in Behavioral Ecology & Sociobiology

Flocks of native Australian birds face extinction

BIRDS of a feather no longer necessarily flock together.

The orange-bellied parrot is one of the world's most endangered birds. Picture: Jane Ollerenshaw Source: Leader

The orange-bellied parrot is one of the world’s most endangered birds. Picture: Jane Ollerenshaw Source: Leader

The King Island and Kangaroo Island emus are extinct as is the vinous-tinted thrush.

Australia has 828 bird species, 45 per cent of which are found nowhere else.

Our isolation has helped the proliferation of unusual birds, from tiny honeyeaters to the flightless emu that stands at almost 2m.

Add to that a diverse range of waterbirds, seabirds, open woodlands and forest dwellers, colourful cockatoos and budgies, enchanting cassowaries, black swans, fairy penguins, kookaburras, lyrebirds and currawongs, plus 55 species of parrots, and we have an eclectic mix.

But, sadly, 23 of our bird species are extinct.

Even our state bird emblem, the helmeted honeyeater, is critically endangered, as are five others, while 44 are endangered, and 61 are vulnerable.

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Melbourne Zoo is breeding the regent honeyeaters while Healesville Sanctuary has captive breeding programs for the helmeted honeyeater and the orange-bellied parrot.

Dr Melanie Lancaster, assistant curator of threatened species at Healesville Sanctuary, says it has been fighting extinction of both species for a long time – since 1989 for the Helmeted Honeyeater and 1994, for the orange-bellied parrot.

“With successful captive breeding we hope to be able to boost the population in the wild,” Dr Lancaster says.

REGENT HONEYEATER

The soft, metallic chiming call of the regent honeyeater (Anthochaera phrygia) is now a rare sound.

It once rang out along the eastern coast of Australia, from Brisbane to Adelaide.

They live in dry box-ironbark eucalypt woodlands and forests, and favour the most fertile areas along river valleys and flats. They feed on the nectar of flowering eucalypts, as well as some invertebrates and lerps.

The highly mobile regent honeyeaters began to decline in 1940s and are no longer found in southwest Victoria. They are probably extinct in South Australia due to habitat destruction.

Melbourne Zoo is breeding regent honeyeaters to help with the recovery of this species.

HELMETED HONEYEATER

This is our state emblem and yet there are less than 70 left of this songbird with black, yellow and olive plumage.

Otherwise known as Lichenostomus melanops cassidix, they are unmissable.

Their crowning glory are beautiful, bright yellow caps of yellow feathers.

They love damp, swampy forests and have suffered during the recent drought.

Dr Lancaster says the small population is still struggling to grow, so Healesville supplements it annually with birds bred there.

“This year we have 14 recruits ready to be released in spring,” he says.

“Helmeted honeyeaters rely on a dense shrub and sedge understory, and are threatened by the die-back of eucalypt and paperbark trees in their stream-side habitat.”

ORANGE-BELLIED PARROT

Neophema chrysogaster, or the orange-bellied parrot, is one of the world’s most endangered birds with only around 30 individuals remaining in the wild.

As the species teeters on the brink of extinction, there’s an insurance policy in the offing. A further 160-170 birds are part of a captive breeding program at Healesville Sanctuary, Adelaide Zoo and Taroona in Tasmania.

Dr Lancaster says despite being small, and weighing only 45-50g, these parrots make an incredible journey across Bass Strait, between southwest Tasmania and the Victorian and South Australian coasts, each year.

They spend winter on the mainland and return to Tasmania to breed.

The captive population is an extremely valuable backstop against complete extinction.

One of only three migratory parrot species in the world, it’s at risk of extinction in the next 3-5 years unless urgent action is taken.

This year, Healesville Sanctuary has bred another 31 birds to add to the tally.

Source: heraldsun.com.au

Calls for buzzards not to be persecuted in Scotland

Buzzard nests and eggs are being destroyed in England

Buzzard nests and eggs are being destroyed in England

Scotland’s leading wildlife conservation charity is calling on the Scottish Government for reassurance that licences will not be issued for the destruction of buzzard nests and eggs in Scotland.

The measure is currently being taken by Natural England – the body responsible for the issuing of these licences in England – to protect non-native pheasant stock.

In the letter, Chief Executive of the Scottish Wildlife Trust, Simon Milne MBE, says: “The Scottish Wildlife Trust always advocates taking management decisions based on the best available scientific evidence.

“Data gathered by the British Association for Shooting and Conservation found that on average the level of predation of game birds by raptors is only 1-2%.

“We do not believe that this comparatively small loss justifies the persecution of this native species and that the vast majority of the public would prefer to see buzzards taking their rightful place in the ecosystem.”

“We are seeking assurance that the Scottish Government and its agencies will not issue such licences in Scotland.”

source: strathspey-herald.co.uk