Tuesday, July 5, 2022

Tracking the impact of plastics

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Dr Jennifer Lavers, The Lord Howe Island Signal

Since 2007, the Adrift Lab research team based in Tasmania has been fortunate to visit Lord Howe Island in Apr/May to study plastics ingested by two mutton-bird species, Wedge-tailed and Flesh-footed Shearwaters. The database contains a wealth of information on the origin of items (e.g., bottle caps, balloon clips) and amount consumed by each bird species. Over time, it’s become one of the longest-running plastic monitoring programs in the world (certainly in the Southern Hemisphere). As seabirds are considered sentinels (or bio-indicators) of ocean health (similar to the proverbial ‘canary in the coalmine’), this data can provide valuable insights into rates of plastic accumulation in our oceans.

GPS on chick
A solar-powered GPS tracking device deployed on a Flesh-footed Shearwater chick. Photo courtesy The Lord Howe Island Signal.

During this time, global awareness of the plastic pollution issue has grown enormously through media articles, documentaries, and research. Despite all this attention, there remain some fundamental questions that scientists are very keen to answer: perhaps the most important is “can exposure to plastic harm animals in ways that contribute to population decline?” It’s a tough question to answer because our wildlife often faced multiple pressures at the same time, such as ocean warming, habitat loss, or invasive species. However, with assistance from cutting-edge technology, in 2022 an exciting new research program was launched on Lord Howe Island that aimed to tackle this challenging question.

In April, the Adrift Lab team arrived on the island carrying tiny GPS tracking devices – these aren’t your average tags though. Each weighed less than 6 g and is 20 mm in size (similar to a $2 coin). The top surface is covered by a tiny solar panel (about the size of your thumbnail), which automatically re-charges the tag as the birds soar across the Pacific Ocean. Inside each tag is a transmitter that communicates with the ARGOS satellites circling Earth. Yep, Lord Howe’s seabirds have gone high-tech and global!

The aim is to track the muttonbirds (specifically chicks 80-90 days old) as they embark on their first-ever flight out to sea. Where do these young birds go when they’re not on Lord Howe? Well, they eventually make their way to the Sea of Japan, but how long this takes or what route they choose is unknown. And this is a critical time for young birds – they must teach themselves to feed and fly while never actually having seen the ocean before! Even more incredible, they don’t have their parents to teach them any of these skills – adult Flesh-footed Shearwaters begin migrating earlier and are likely halfway to the Sea of Japan by the time the chicks are ready to go.

Deploying the GPS tags on chicks that were fed plastic, as well as chicks that were not, has provided the Adrift Lab team with remarkable data on how the behaviour and survival of these birds differs once they leave the Island.

Birds exposed to plastic often have reduced body size and lower fat stores, we suspect this will impact their first migration. Will these plastic-impacted birds make it 7,000 km north to the Sea of Japan? Perhaps their journey will take longer, or some may never make it. The truth is, we don’t know and only time will tell.

Tracking
Image courtesy The Lord Howe Island Signal.
Tracking
Image courtesy The Lord Howe Island Signal.
Adrift Lab team
The Adrift Lab team (from left to right) on Lord Howe: Megan, Jenn, Alex, Alix, and Jack.
Photo courtesy The Lord Howe Island Signal.

In the meantime, due to one of the remarkable features of the GPS tags, we can track the chicks’ movements in real time (using the satellite data), following the birds as they leave the safety of Lord Howe’s beaches and lagoons, venturing out into the big blue. We’re excited to share with you some preliminary data: two birds we tracked in May – the first image is from a bird that was fed more than 50 pieces of plastic while the bird in the second image consumed only one piece. Stay tuned for more updates as we track these young birds during their first year at sea.

Other exciting things to watch out for: during our time here on the island this year we were joined by Australian Geographic Magazine. The upcoming June/July issue will feature Adrift Lab’s research on the shearwaters, including the tracking project (we’re hopeful one of Justin’s photos will grace the front cover).

We also had a small team from Envoy Films shadowing us for a week – the footage they collected will be featured in an upcoming 3-part documentary on Australia’s natural history which will premier (on Australian television) in early-2023.

Acknowledgements: Adrift Lab would like to extend a heartfelt thanks to the LHI community for their incredible support over the past 15 years. From dropping off birds to logistical advice and hands-on assistance in the field, this project would not be what it is without you! Special thanks to Caitlin, Justin, Jack, Cindy, Therese, Nicola, Leon and Stephen for your enthusiasm, laughter, and endless generosity. As we say at Adrift Lab, good people, good science.

The Lord Howe Island Signal 31 May 2022

This article appeared in The Lord Howe Island Signal, 31 May 2022.

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