The Biology, Agriculture, and Paleontology thread

In the 2011 animated film Rio, Blu, a captive-raised Spix’s Macaw, arrives in Brazil to mate with the last-known wild member of his species a female named Jewel. But according to our latest paper, Blu was already 11 years too late – Jewel, the last of her kind, likely perished in or around 2000.

Spix’s Macaw Cyanopsitta spixii is one of eight species primed to have their extinctions either confirmed or deemed highly likely, following a new study by BirdLife International. The eight-year study used a new statistical approach to analyse 51 Critically Endangered species, quantifying three factors at once: intensity of threats, timing and reliability of records, and the timing and quantity of search efforts for the species. Five of the eight confirmed or suspected extinctions took place on the South American continent, four of them in Brazil, reflecting the devastating effects of the high rate of deforestation in this part of the world.

“Ninety per cent of bird extinctions in recent centuries have been of species on islands” says Dr Stuart Butchart, BirdLife’s Chief Scientist and lead author on the paper. “However, our results confirm that there is a growing wave of extinctions sweeping across the continents, driven mainly by habitat loss and degradation from unsustainable agriculture and logging”.

Of the eight species, it was recommended that three species should be re-classified as Extinct; the Cryptic Treehunter Cichlocolaptes mazarbarnetti and Alagoas Foliage-gleaner Philydor novaesi, two ovenbirds from North-east Brazil, and Poo-uli Melamprosops phaeosoma, formerly of Hawaii, which has not been seen in the wild since 2004 (the same year the last captive individual died). The data also suggests another four species should be reclassified as Critically Endangered (Possibly Extinct), a category that indicates that the species is highly likely to be extinct, but further search efforts are required before we can definitively rule it to be Extinct.

These species are New Caledonian Lorikeet Charmosyna diadema (last sighted in 1987), Javan Lapwing Vanellus macropterus (1994), Pernambuco Pygmy-owl Glaucidium mooreorum (2001) and another Brazilian macaw, Glaucous Macaw Anodorhynchus glaucus (1998).

Hope still persists for the Spix’s, however, despite the Brazilian endemic apparently being wiped out in the wild as a result of deforestation and other factors such as the creation of a dam and trapping for wild trade. An estimated population of between 60-80 persists in captivity, hence the suggested classification change to Extinct in the Wild. A lone sighting in 2016 sparked hope the species may persist in the wild, but it is now suspected to be an escapee from captivity. If so, it is sadly highly unlikely this Blu ever found his Jewel.

any pterosaurs filling various niches now filled by birds (vulture-like scavenger, nectar-eater, etc.)

a proto-pterosaur

an arboreal non-avian dinosaur

a cold-blooded bird or mammal

a bird with functional wingclaws as an adult

Humpback whales, once hunted around the world to the point that they became so rare that the industry built on their blubber went belly-up, is booming.

The world's largest humpback whale population is particularly strong in Australia's Kimberley, a region that provides ideal and undeveloped calving grounds, researchers say.

Since the whaling stations were closed, humpbacks that visit Western Australia have become the good news story that defies the trend of environmental doom and gloom.

Many travel all the way up Australia's west coast to the remote Kimberley — a region twice the area of the United Kingdom with just 50,000 residents.

So why do whales visit the Kimberley and what threats do they face?

That was a question audience member Ric Kornaus put for the ABC to investigate for our Curious Kimberley series.

Mr Kornaus first visited the Kimberley in the 1980s and enjoyed camping on the remote coast north of the small town of Broome.

Since that time, Broome has become a popular tourist destination and mining and gas projects have been developed along the coast, prompting Mr Kornaus to ask what impact this has had on the whales that visit the Kimberley.

"What is the affect on them, whether their numbers are dropping or static, or what?" he asked.

Back from the brink

Curt Jenner and his wife Micheline started studying humpback whales on the west coast of Australia almost 30 years ago in an effort to find out if they could recover from near annihilation.

Humpback whales had been hunted at an increasing rate in the early 20th century as technology such as faster ships and exploding harpoons were developed, until populations crashed.

"Back in the early '60s this population was declared uneconomic to whale because the population had been decimated to the point that there was probably only about 500 animals left," Mr Jenner said.

But as the first scientists to investigate humpback whale recovery in Western Australia back in 1990, Mr Jenner and his wife found the population recovery was difficult to comprehend, and it has continued growing at an astonishing rate.

"These are the most successful humpback whales, population-wise, of any humpback whale population on the entire planet," Mr Jenner said.

Dr Kelly Waples is a research scientist with the WA Department of Biodiversity Conservation and Attractions, and she says Western Australia's humpback whales lead the world in terms of population recovery.

"It's one of the best recovery stories for these large whales," Dr Waples said.

"It's been estimated that they've been increasing at about 10 per cent per year, which is the maximum rate that a population can recover at."

In the subsequent decades of study, the Jenners have started to piece together why these WA whales have done so well, once again becoming the world's largest population.

Natural nursery

Like most humpback whales around the world, the WA population leads a feast and famine existence.

They spend summer in Antarctic waters, fattening on krill and small fish, and then migrate to the tropics.

It is one of nature's great feats of endurance for the pregnant female humpbacks, travelling north up Australia's west coast to give birth and providing their calves with the milk that is their sole source of sustenance, all without feeding until returning to Antarctica.

The success of WA's humpback whales appears to be a combination of good feeding grounds in Antarctica, coupled with calving grounds in the Kimberley that ease the demands the migration places on mother and calf.

The pygmy blue whale is another species that migrates between Antarctica and the tropics, and Mr Jenner says its comparatively slow recovery highlights the importance of the Kimberley to the humpback's success.

"The pygmy blue whales that we've been studying off the Western Australian coast give birth up in Indonesian waters," Mr Jenner said.

"There's a lot of plastic, there's a lot of ocean pollution, and there's also an enormous amount of shipping traffic which could either be disruptive or potentially quite dangerous for them."

Safety from killers

The Kimberley's lack of the natural predators of whales may also be the secret to the success of WA's humpbacks.

As numbers boomed after human hunting ceased, the numbers of natural predators also increased.

"Both great white sharks and killer whales are predators of humpback whales, in particular the calves," Dr Waples said.

"As we've seen the recovery of humpback whales, we've also seen more killer whales around."

Killer whales have increasingly been seen attacking humpback calves along the WA coast as far north as Exmouth Gulf.

But further north in the Kimberley, humpback calves can be born and grow for their first few weeks unmolested by killer whales.

"By the time a humpback calf is one month old they have almost doubled in weight," Mr Jenner said.

"It goes from an animal that is extremely vulnerable to one that can hold its breath as long as its mum."

This allows humpback whale calves to increase their chances of not falling prey to killer whales as they make their way back south to the Antarctic feeding grounds.

No sign of stopping

Most experts agree that WA's humpback whales are probably close to reaching their natural population levels before human impacts.

But without knowing what the historic population was, and it being nearly 10 years since the last population count was made, there is quite a bit of guesswork involved.

"We think they're getting up close to around carrying capacity, we don't quite know, but it's certainly getting up to reasonable numbers again," Dr Waples said.

What is certain is that so far there is no sign of humpback population growth slowing down.

Cameron Birch has been taking tourists out on the water to look at WA's humpbacks for almost 20 years, first at Coral Bay and now off Broome.

"The population of humpbacks has just increased exponentially," Mr Birch said.

At a time when it can seem that human interaction with the natural environment can only mean bad news, Mr Jenner said the humpback whales of WA are sending us an important message.

"We need to take advantage of this opportunity and understand what these whales are for us," Mr Jenner said.

"They are beacons of good hope and also beacons of good health for the entire ocean."