Balloons have been identified as as a major threat to the seabirds traversing the world’s oceans and mistakenly feeding on plastic.

While soft plastics only accounted for 5 per cent of the plastics consumed by albatrosses and other birds, a new study found they were responsible for 40 per cent of deaths.

Researchers at the University of Tasmania in Australia concluded that while harder shards tend to pass quickly through the gut, softer pieces are more likely to cause blockages.

One in five birds that consumed balloons died, the scientists said.

“Among the birds we studied the leading cause of death was blockage of the gastrointestinal tract, followed by infections or other complications caused by gastrointestinal obstructions,” said PhD student Lauren Roman, who led the study. “Balloons or balloon fragments were the marine debris most likely to cause mortality.”

Plastic waste across the world: in pictures Show all 15 1 /15 Plastic waste across the world: in pictures Plastic waste across the world: in pictures A father and son on a makeshift boat made from styrofoam paddle through a garbage filled river as they collect plastic bottles that they can sell in junkshops in Manila. The father and son team earn some three US dollars a day retrieving recyclables from the river. AFP/Getty Plastic waste across the world: in pictures A composite image of items found on the shore of the Thames Estuary in Rainham, Kent. Tons of plastic and other waste lines areas along the Thames Estuary shoreline, an important feeding ground for wading birds and other marine wildlife. Getty Images Plastic waste across the world: in pictures Children collect plastic water bottles among the garbage washed ashore at the Manila Bay. According to the United Nations Environment Programme, at current rates of pollution, there will likely be more plastic in the sea than fish by 2050. AFP/Getty Plastic waste across the world: in pictures Plastics and other detritus line the shore of the Thames Estuary. In December 2017 Britain joined the other 193 UN countries and signed up to a resolution to help eliminate marine litter and microplastics in the sea. It is estimated that about eight million metric tons of plastic find their way into the world's oceans every year. Once in the Ocean plastic can take hundreds of years to degrade, all the while breaking down into smaller and smaller 'microplastics,' which can be consumed by marine animals, and find their way into the human food chain. Getty Plastic waste across the world: in pictures A dump site in Manila in 2013. The Philippines financial capital banned disposable plastic shopping bags and styrofoam food containers, as part of escalating efforts across the nation's capital to curb rubbish that exacerbates deadly flooding. AFP/Getty Images Plastic waste across the world: in pictures Children swims in the sea full of garbage in North Jakarta, Indonesia. Getty Plastic waste across the world: in pictures An Indian woman holds a jar filled with Yamuna river water polluted with froth and toxic foam to be used for rituals at the river bank in New Delhi, India. The Yamuna River, like all other holy rivers in India, has been massively polluted for decades now. The river that originates in a glacier in the pristine and unpolluted Himalayas, and flows through Haryana, Delhi and Uttar Pradesh before merging with the Ganges River in Allahabad, once used to be the lifeline of the Indian capital. Currently, it is no more than a large, open sewer that is choking with industrial and domestic discharge that includes plastic, flowers and debris and has virtually no aquatic life. EPA Plastic waste across the world: in pictures Plastic waste is washed up on South Troon beach in Scotland. Recent reports by scientists have confirmed, plastics dumped in the world oceans are reaching a dangerous level with micro plastic particles now being found inside filter feeding animals and amongst sand grains on our beaches. Getty Plastic waste across the world: in pictures Children collect plastic to be sold and recycled, in a polluted river in suburban Manila. The city's trash disposal agency traps solid waste floating down waterways that was thrown into the water by residents of slums along riverbanks upstream. AFP/Getty Plastic waste across the world: in pictures View of the Carpayo Beach in La Punta, Callao, some 15 km of Lima. In 2013, the NGO VIDA labeled the Carpayo Beach as the most polluted in the country - 40 tons of trash on each 500m2. AFP/Getty Plastic waste across the world: in pictures Trash from Kamilo Beach in Hawaii. Gabriella Levine/Flickr Plastic waste across the world: in pictures A scavenger collects plastic cups for recycling in a river covered with rubbish near Pluit dam in Jakarta. Reuters Plastic waste across the world: in pictures Rubbish fills Omoa beach in Honduras. Floating masses of garbage offshore from some of the Caribbean's pristine beaches are testimony to a vast and growing problem of plastic pollution heedlessly dumped in our oceans, locals, activists and experts say. AFP/Getty Plastic waste across the world: in pictures A man climbs down to a garbage filled river in Manila. Plastic rubbish will outweigh fish in the oceans by 2050 unless the world takes drastic action to recycle the material, a report warned in 2016. AFP/Getty Plastic waste across the world: in pictures Garbage on East Beach, Henderson Island (Pitcairn Islands), in the south Pacific Ocean. The uninhabited island has been found to have the world's highest density of waste plastic, with more than 3,500 additional pieces of litter washing ashore daily at just one of its beaches. EPA

The scientists used cause-of-death data for 1733 seabirds of 51 species.

While they identified just five balloon-related deaths, the team are concerned this relatively rare variety of plastic may cause a disproportionate number of deaths, as birds confuse them with squid.

Plastic ingestion is now recognised as a major global threat to marine life, particularly seabirds, with 250 000 tonnes of marine debris currently floating in the world’s oceans.

Over a quarter of seabird populations are experiencing serious population declines and scientists think their habit of mistaking marine debris for food is a likely driver of this problem.

Grey headed albatross autopsy with balloon debris (Lauren Roman)

One study led by Dr Chris Wilcox from the Commonwealth Scientific and Industrial Research Organisation estimated 99 per cent of seabirds around the world would be eating plastic by the middle of the century.

Dr Wilcox, who also worked on the latest seabird study – published in the journal Scientific Reports – said the new approach for analysing the impact of plastic had previously been trialled in turtles.

“These two applications are the first time there has been a robust estimate of the impact of plastic ingestion on free living marine species,” he said. “This is a critical step in triggering action to address plastic pollution.”

Their results show conclusively that the more plastic a bird eats, the more likely it is to die.

Previous work has shown that besides the physical blockages of plastic in a bird’s gut, plastic can also leach potentially harmful chemicals into their bodies.

One recent study found traces of plastic-derived chemicals in the eggs of northern fulmars inhabiting the remote Arctic.