A new study off the coast of Tasmania has revealed that seabirds show strong colour preferences when foraging at sea – a discovery that could help mitigate two of the greatest human-driven threats they face: plastic ingestion and longline fishing bycatch.

Published in Animal Behaviour, the research marks the first time seabird colour preferences have been tested during real-time feeding behaviour in the wild, offering rare insight into how these ocean wanderers interact with debris and bait on the surface of the sea.

Led by Elliot Styles, a recent Honours graduate from the University of Tasmania’s Institute for Marine and Antarctic Studies (IMAS), the team conducted 117 field trials over the continental shelf in southeastern Tasmania. Wild seabirds were presented with identical baits dyed in six different colours – white, yellow, red, green, black and blue – and the researchers documented which colours were most often eaten, and by which species.

“This is the first time seabird colour preferences have been tested while the birds were actively feeding,” said Styles.

“Until now, most of what we knew came from analysing regurgitated boluses or stomach contents after death, but that doesn’t tell us what colours the birds had to choose from. Our approach eliminates that uncertainty – and opens the door to an entirely new avenue of seabird research.”

The findings were striking. Shy-type albatrosses (Thalassarche cauta and Thalassarche steadi) and kelp gulls (Larus dominicanus) dominated the trials. Both species showed clear preferences: white baits were most commonly taken, followed by yellow and red, then green and black – with blue emerging as the least preferred option.

“Seabirds aren’t just opportunistic feeders – they’re making choices, and those choices include colour,” said IMAS ecologist and co-author Dr Lauren Roman. “This study is the first to quantify those preferences in a field setting, and the implications are wide-reaching.”

The work comes at a time when the world is grappling with seabird mortality linked to human marine activity. Many seabirds mistake floating plastic for prey, especially if it resembles squid, a preferred food source. Meanwhile, bycatch from longline fisheries continues to drive population declines in albatrosses and petrels worldwide.

Styles believes the findings could inform practical solutions. “Blue-dyed bait has previously been trialled in some longline fisheries, but it’s been controversial. In 2023, the Agreement for the Conservation of Albatrosses and Petrels (ACAP) advised against it due to a lack of experimental evidence,” he said. “Our study suggests that blue may, in fact, be effective – at least for some species. That’s a huge opportunity for follow-up research.”

Competition between species also played a role. “We saw Shy-type albatrosses dominating access to their preferred colours, often leaving the lower-ranked baits for gulls,” Styles explained. “That behaviour also helps us understand how changes in seabird community dynamics could impact exposure to risk.”

Beyond fisheries, the study raises important questions about the colour of materials commonly lost at sea – including fishing gear and weather balloons, many of which are white or grey.

“Fragments of weather balloons resemble squid when floating at the surface, which makes them especially dangerous,” Styles said. “Simply switching to colours seabirds avoid – like blue or black – could significantly reduce the risk.”

As our oceans continue to be shaped by human activity, the researchers hope this evidence-based approach to seabird behaviour can inspire policy change.

“Understanding what seabirds see and choose is key to designing safer oceans,” said Dr Roman. “This data adds a valuable piece to the puzzle – and it underscores the need to consider even the subtlest factors, like colour, when working to protect these species.”

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