On Scotland’s remote St Kilda island in the summer of 1840, a group of fishermen found a strange seabird sleeping on a ledge. It was black-and-white, flightless, and enormous. The men took it home to their village and tied it up in a stone hut.
For three days the bird complained and tried to bite anyone that came near. Then a wild storm arose. Fearful the bird was a witch, and had sent the tempest to punish them for capturing it, the superstitious villagers stoned it to death. It took an hour to die.
In reality, the witch-bird was a great auk—the last one ever documented in the British Isles. Four years later, the last pair in existence was killed in Iceland by hunters looking for museum specimens.
The species—sometimes known as the penguin of the north—had ranged across the North Atlantic in the millions. What happened? Was the species in decline before intensive harvesting started in the 1500s—or was human hunting alone enough to drive such a numerous species into oblivion?
To find out, genetic researcher Jessica Thomas from the University of Swansea analysed the mitochondrial DNA of 41 long-dead great auks. The data showed the species had enjoyed high genetic diversity and a constant population size for thousands of years, and that great auks from across the North Atlantic were able to meet and breed.
The researchers then simulated how much hunting would have been necessary to drive the great auk to extinction within 350 years, and found that an annual harvest of 210,000 birds and fewer than 26,000 eggs would have inevitably led to extinction.
Sailors’ journals and other historic reports suggest the actual number of birds killed for their meat, eggs, and feathers is likely to have been far higher. Then the museum trade finished them off.
“There are lot of very gruesome sailors’ records in terms of how they used to kill them,” says Thomas. “They would have these huge pits where they would corral the great auks into stone huts and then burn them with the oil from their dead relatives.”
The study highlights that “pretty much anything is susceptible to extinction”, says study co-author Michael Knapp from the University of Otago, where Thomas was based for some of her research.
“People went to the North Atlantic and it was full of great auks. Nobody would have thought there was any risk.”
Some of the great auk’s relatives—the puffin, the murre—are still hunted today, and should be more closely monitored, says Knapp. “Anything we exploit in large numbers we need to be very careful about, even if we think there’s a lot of them.”
The largest animals in the ocean weren’t always mammals. They were birds.
A newly discovered penguin was the size of a human—1.6 metres tall, weighing 80 kilograms. Its bones were unearthed from the Waipara Greensands in North Canterbury in 2011 by Leigh Love, an amateur palaeontologist.
One of the fossils, encased in rock, sat in a display cabinet in Love’s living room for years. “I would use it for the fossil talks I did with school groups coming in,” says Love. “This thing would get passed around the kids: ‘Here’s something that’s about 60 million years old’.”
In 2018, Love started to learn fossil preparation—the art of removing the rock to leave the bone exposed. He practised on a crab, then had a go at the penguin leg. It was soon clear it was a new species, dating from a time when penguins ruled the waves.
“Marine mammals took 30 million years to evolve, so there was an ‘age of the giant penguins’ in the oceans for 30 million years before finally the whales and seals took over,” says Paul Scofield of Canterbury Museum. “There was a possibility that penguins were going to become whale-size—all the genes for true giganticism are in a bird, because they are dinosaurs. But it never happened, because mammals took over that niche.”
On the island sanctuary of Whenua Hou, kākāpō only breed when rimu trees mast. Rimu responds to different temperature cues than beech.
“If year two is colder than year one, there’ll be a mast in year four,” says kākāpō scientist Andrew Digby. “We count the developing fruit in the autumn. If more than eight per cent of the branch tips have fruit on them, the kākāpō will breed the following summer.”
Last autumn, 47 per cent of the tips had fruit, and it has led to a record-breaking breeding season.
It’s rare for rimu fruit, pictured above, to fully ripen on Whenua Hou—that last happened 17 years ago.
But today, ripe red fruit carpet the ground, and kākāpō mums are feeding it to their chicks, which are growing faster than usual. Almost every nest has two chicks, or even three: “We’ve never seen that before,” says Digby. “Almost every bird has bred.”
It means 2019 is a mega-mega-mast: not only are beech and rimu masting at the same time, a rare event, but masting is unusually widespread.
Since humans arrived in New Zealand, we’ve lost nearly half of our native terrestrial bird species. Some of those extinct icons are well known, while others are recalled only by myth and bones. We will probably never know the full polyphony of that primordial dawn chorus, but old bones and new science are giving us a richer picture of life in the land of birds, back when they still ruled the roost. For the first time, we’re able to answer questions about what they ate, where they came from, how they were related to each other, and how they got so much bigger, heavier, and weirder than their ancestors.