A chance meeting between two very different scientists has solved the mystery why three million dead birds washed up on Australia’s east coast eight years ago.
In 2013, there was a massive death of short-tailed shearwaters, which researchers have now discovered was caused by starving birds that ate volcanic rock and plastic in desperation.
CSIRO scientist Lauren Roman, a seabird plastic congestion researcher, said it was a strange coincidence that the hundreds of seabirds that washed up on a beach right next to her research station were full of pumice.
“Very close to the research station where I was working at the time, there were over 100 birds dead and dying … along every mile of this very, very long beach,” she told Daily Mail Australia.
While working at the Moreton Bay Research Center on North Stradbroke Island, Ms. Roman recruited science students to collect the birds and put them in a freezer for later viewing.
Researchers found dead birds washed up on Australia’s east coast eight years ago
After a few weeks, she realized the dramatic mass death was happening not just in her backyard, but thousands of miles on Australia’s east coast, from Fraser Island in the north to Tasmania in the south.
Even more unusual was what researchers found in the birds when they performed auto-necropsies – four or five pumice stones, which are floating, aerated volcanic rocks.
‘Occasionally you will find a few pumice stones in a seabird, but you don’t often find many. And they don’t find them in the stomachs of just about every bird, ”said Mrs. Roman.
Their mass deaths of 3 million Short-tailed Shearwaters in 2013 (photo)
The shocking discovery raised more questions than answers, especially as veterinary autopsies showed the birds were in bad shape and possibly starving to death.
There was no way Mrs. Roman could solve the riddle on her own, but another coincidence connected her to the expert she needed.
One of the students hired to collect the birds with Mrs. Roman had Scott Bryan as her supervisor – who happened to be an expert in pumice rafts, which are massively floating rocks on the ocean after volcanic eruptions.
The birds turned out to be full of pumice, a volcanic rock (photo), astonishing researchers
“Scott and I all had very different disciplines … you wouldn’t find us in the same building or talk to each other,” Mrs. Roman said.
“But neither of us could have solved this mystery without the other’s expertise.”
A question was formulated in a team consisting of Dr. Kathy Townsend, Dr. Natalie Bool and the then third-year student who linked the two researchers, Leah Gustafson.
Did the birds die because they ate the volcanic rock, or did they eat it because they were starving?
An eight-year investigation into the mystery revealed where the rock came from
First, the group had to figure out where these birds were – luckily for Ms. Roman, a woman she sat next to as a student who had followed the migration patterns of this particular bird species for years, which was consistent every year.
Next, Mr. Bryan and Mrs. Gustafson had to identify the origin of the rocks, and they used satellite systems to discover that it came from the 2012 Havre eruption in the Kermadec arc north of New Zealand.
Ordinarily, the ocean birds would feast in the Arctic circle before migrating to the Southern Hemisphere for ten days, where they would breed in Victoria or Tasmania, and occasionally even as far as Antarctica.
“We realized that the birds could only have interacted with that pumice stone in the few days before they died,” Ms. Roman said.
So they must have already been in very bad shape and very, very hungry the moment they interacted with it with the pumice raft.
‘If they were fat, they would have just flew past there. They wouldn’t have stopped trying to feed desperately because otherwise they wouldn’t have a reason to stop. ‘
Researchers concluded that the birds ate the pumice stone (pictured) because they were starving
The next step for the researchers is to determine why the birds were starving.
They think it is likely they were starving in the Northern Hemisphere.
One possible explanation is that a marine heat wave in the north from 2013 to 2016 – dubbed the Blob – decimated the species that feeds on shearwater.
Another reason is that because the bird species and the pink salmon – which are artificially reared and released – feed on the same food, the fish could have stolen all of the shearwater’s usual prey.
The next step for scientists is to find out why the birds were starving
Ms. Roman hopes to receive a grant to continue the quest to solve the puzzle, and she predicts that climate change could affect the birds.
“Climate change is a serious threat to many different bird species,” she said.
‘But it’s something that’s pretty hard to research, because you’re looking at changes in a bird that are very, very hard to find.
‘They’re out. They live in the middle of the sea. It is very difficult to know what will kill them when they disappear again, because they live in the middle of the ocean. ‘