You might think that life in the skies would make birds safe from the dangers of plastic. Think again.
The sheer scale of global plastic production means that no species is beyond its reaches, and if we allow things to continue as they are the situation is only going to get worse.
In Australia alone we manufacture almost 3 million tonnes of plastic every year, but only recycle 12%. So how exactly does all this waste this affect birds?
How many birds die from plastic?
A lot of the data regarding birds and plastic comes from studies of seabirds, as the presence of plastic in the ocean has garnered a lot of media attention.
The number of seabirds dying as a result of plastic is currently estimated at 1 million a year. This shocking statistic becomes even more worrying when we consider just how quickly this problem has grown. Fewer than 5% of seabirds studied in 1960 were found to have plastic in their stomachs, but this number had rocketed to 80% in 1980.
Based on this research, and contemporary studies, it's expected that by 2050 99% of all seabird species will be ingesting plastic. Along with entanglement, this is one of the leading causes of plastic-related deaths among birds.
Why do birds eat plastic?
The images of chick skeletons with stomachs full of plastic make for tough viewing, but this is the reality of life and death for many of the world's seabird populations.
There are a few reasons why seabirds are ingesting plastic:
- It looks like food - Small particles of plastic floating in the ocean can be easily mistaken for prey.
- It smells like food - Studies show that the smell of krill feeding on the algae that coats marine plastic debris is similar to natural scents that many seabirds follow when hunting for food.
- It floats - Plastic's lightweight nature is also a huge part of the problem. Albatross species, in particular, feed by skimming low over the water and inadvertently consume plastic as a result.
While this is a global phenomenon, species close to home are suffering some of the worst of the effects. The flesh-footed shearwater, which breeds on Lord Howe Island, and is a common visitor to waters off mainland Australia, ingests more plastic as a proportion of its body mass than any other marine creature.
Plastic is able to reach these remote locations due to winds and currents that can carry it many thousands of kilometres from where it originally entered the ocean. This means that formerly safe island breeding colonies are now flooded with deadly waste.
What happens to birds that consume plastic?
The impacts of plastic consumption for birds depend on what they eat. Some birds die quickly as a result of sharp plastics puncturing their internal organs, but others may starve to death as they feel full from eating plastic, but receive no nutritional benefit.
Emerging evidence also suggests that, due to the amount they're eating, birds are at risk of the toxic effects of the chemicals that coat plastics.
Tragically, adults birds that leave nests to hunt often return with plastic they have mistaken for food and feed it to their chicks. The juveniles' smaller stomachs are even less able to deal with the effects of the plastic and many don't make it to adulthood.
How do birds die from plastic entanglement?
The other common way that plastic kills birds is through entanglement.
By this we mean birds getting stuck in plastic waste and, with 8 million tonnes of plastic entering the world's oceans every year, avoiding this fate is becoming more and more difficult.
One of the worst offenders when it comes to ensnaring marine life is abandoned fishing gear. In Queensland alone it's estimated that 35 traps are lost per boat per year for blue swimmer crab fishing alone, and around the world 27% of all marine litter consists of lost nets, lines and traps. This discarded equipment continues to catch wildlife in a phenomenon that has come to be known as 'ghost fishing'.
Data for the exact number of seabirds caught in this way is patchy, but some reports estimate that one-fifth off all seabird species are affected by entanglement or ingestion of marine debris.
What happens to birds that become entangled in plastic?
This really depends on where and how the birds become entangled. Outcomes can include:
Drowning in nets - For gannets, penguins and other birds that dive for their food, becoming caught in underwater plastic will mean they can't get back to the surface, and so they drown.
What can I do?
The problem with plastic is that it takes hundreds of years to break down, so this is an issue that isn't going to go away.
With such huge figures being thrown around it can feel like individual efforts won't have much of an impact, but this isn't the case. Here are a few ideas for how you can work to minimise the risk of plastic to birds:
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