When I graduated from university some of the people I was working with were working with the local bird group here in Hobart. And they were going out on a regular basis catching migratory shorebirds that breed up in Siberia and then spend six months down here in south-east Tasmania.
So it was another opportunity for me to go out and catch the wildlife, to learn about species that don’t even breed here in Tasmania but come from the northern hemisphere. Working with this shorebird study group back in the 1980s, we were out catching these birds every weekend we could during the summer months when the tides worked out, and that’s how we could calculate over multiple years how long these birds lived.
We know now that some of the smallest birds, like the red necked stint - that weighs 25 to 28 grams, less than an ounce in the old measure – takes six weeks to fly from Siberia to Tasmania.
It spends six months down here, then turns around, goes back to Siberia and does it all over again. We know from our banding records back in the 1980s that these birds can live for 20 years.
A couple of years ago we had a bird, a bar-tailed godwit – a 250 to 300 gram bird - it flew from Alaska to Tasmania non-stop in 11 days. It was travelling a thousand kilometres every 24 hours.
It didn’t land anywhere. It flew continuously and it got halfway across the Tasman Sea. Left was New Zealand and right was Tasmania and there was a low-pressure system and it was just pushed towards Tasmania and came ashore at Ansons Bay.
So it flew from Alaska to Ansons Bay in one continuous flight. It was flapping its wings every metre along that 11 thousand kilometres.
How is that even possible?
If we take a step back about 10 or 15 years ago this question - how far can our migratory shorebirds actually fly in a single hop? - was really prevalent. We knew from all the research that had been done that some birds do little hops - smaller birds will do a short hop, feed up again then do another hop and feed up - and so they basically build up their body reserves in terms of fat and then they’ll fly as far as they can on that fat reserve. When those fat reserves are depleted they’ll land somewhere, feed up again and then keep going.
So birds like the rednecked-stint will take six weeks because it’s stopping along the way between here and Siberia. Where as other birds like the godwits and some of the bigger birds, the assumption was some of these birds were landing on deserted atolls or uninhabited islands in the Pacific on their migration between Alaska and Tasmania or Tasmania and New Zealand.
But nobody really knew where these birds were flying. I think about 2010 or 2011 they put the first package on – they had to wait for the technology to get small enough so it wouldn’t have an impact on the bird’s flight – and lo and behold the first bird they put the package on was a bar-tailed godwit. It flew from Alaska to New Zealand non-stop – 13 thousand kilometres in 11 days.
The bird doubles its body weight in preparation for migration, and once it has enough reserves to start and the weather is good it’ll start flying. Sometimes they’ll be flying into a headwind and sometimes they have a tailwind.
It’s not like they’re flying up into the jet stream and getting assisted by the air – it’s powered flight the whole way through.
So when we realised how far these birds could fly, the question came back to how could they do it physiologically? It defied our understanding of the physiology of these birds.
So we know now they’re very good at metabolising their energy reserves – they use up every ounce of fat that they put on before they depart.
But then, if they get to the point where they’ve run out of their fat reserves, they’ll actually start breaking down their tissues. So they’ll break down their muscle mass to use that as an energy source.
That’s a destructive process as you can imagine, because they need those muscles to fly to get them through to New Zealand or Australia. If they’re using that muscle and breaking down that muscle for energy reserves, they’re probably not going to make it.
This is what I’m saying - I don’t have to exaggerate what the birds do. What they do is so remarkable. The fact they’re such tiny little things…
Everyone thinks oh yeah, albatross can fly 20 thousand kilometres on a single trip. Sure, but they can land on the water when they get tired or when they’re feeding – but the shorebirds have no webbing in their toes so they can’t land on the water.
As soon as they land on the water, they’re dead. They have no way of getting off the water and continuing their flight.
Once we know how remarkable these birds are, for me the privilege is working with these birds and having exposure to these birds and being able to communicate what these birds do, to the broader community.
Dr Eric Woehler
When I graduated from university some of the people I was working with were working with the local bird group here in Hobart. And they were going out on a regular basis catching migratory shorebirds that breed up in Siberia and then spend six months down here in south-east Tasmania.
So it was another opportunity for me to go out and catch the wildlife, to learn about species that don’t even breed here in Tasmania but come from the northern hemisphere. Working with this shorebird study group back in the 1980s, we were out catching these birds every weekend we could during the summer months when the tides worked out, and that’s how we could calculate over multiple years how long these birds lived.
We know now that some of the smallest birds, like the red necked stint - that weighs 25 to 28 grams, less than an ounce in the old measure – takes six weeks to fly from Siberia to Tasmania.
It spends six months down here, then turns around, goes back to Siberia and does it all over again. We know from our banding records back in the 1980s that these birds can live for 20 years.
A couple of years ago we had a bird, a bar-tailed godwit – a 250 to 300 gram bird - it flew from Alaska to Tasmania non-stop in 11 days. It was travelling a thousand kilometres every 24 hours.
It didn’t land anywhere. It flew continuously and it got halfway across the Tasman Sea. Left was New Zealand and right was Tasmania and there was a low-pressure system and it was just pushed towards Tasmania and came ashore at Ansons Bay.
So it flew from Alaska to Ansons Bay in one continuous flight. It was flapping its wings every metre along that 11 thousand kilometres.
How is that even possible?
If we take a step back about 10 or 15 years ago this question - how far can our migratory shorebirds actually fly in a single hop? - was really prevalent. We knew from all the research that had been done that some birds do little hops - smaller birds will do a short hop, feed up again then do another hop and feed up - and so they basically build up their body reserves in terms of fat and then they’ll fly as far as they can on that fat reserve. When those fat reserves are depleted they’ll land somewhere, feed up again and then keep going.
So birds like the rednecked-stint will take six weeks because it’s stopping along the way between here and Siberia. Where as other birds like the godwits and some of the bigger birds, the assumption was some of these birds were landing on deserted atolls or uninhabited islands in the Pacific on their migration between Alaska and Tasmania or Tasmania and New Zealand.
But nobody really knew where these birds were flying. I think about 2010 or 2011 they put the first package on – they had to wait for the technology to get small enough so it wouldn’t have an impact on the bird’s flight – and lo and behold the first bird they put the package on was a bar-tailed godwit. It flew from Alaska to New Zealand non-stop – 13 thousand kilometres in 11 days.
The bird doubles its body weight in preparation for migration, and once it has enough reserves to start and the weather is good it’ll start flying. Sometimes they’ll be flying into a headwind and sometimes they have a tailwind.
It’s not like they’re flying up into the jet stream and getting assisted by the air – it’s powered flight the whole way through.
So when we realised how far these birds could fly, the question came back to how could they do it physiologically? It defied our understanding of the physiology of these birds.
So we know now they’re very good at metabolising their energy reserves – they use up every ounce of fat that they put on before they depart.
But then, if they get to the point where they’ve run out of their fat reserves, they’ll actually start breaking down their tissues. So they’ll break down their muscle mass to use that as an energy source.
That’s a destructive process as you can imagine, because they need those muscles to fly to get them through to New Zealand or Australia. If they’re using that muscle and breaking down that muscle for energy reserves, they’re probably not going to make it.
This is what I’m saying - I don’t have to exaggerate what the birds do. What they do is so remarkable. The fact they’re such tiny little things…
Everyone thinks oh yeah, albatross can fly 20 thousand kilometres on a single trip. Sure, but they can land on the water when they get tired or when they’re feeding – but the shorebirds have no webbing in their toes so they can’t land on the water.
As soon as they land on the water, they’re dead. They have no way of getting off the water and continuing their flight.
Once we know how remarkable these birds are, for me the privilege is working with these birds and having exposure to these birds and being able to communicate what these birds do, to the broader community.
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