Mistaken for food, the plastic we throw away can end up in the stomachs of seabirds, where it remains for the rest of the birds’ lives.  Finding these undigestible parts is not a new occurrence. In fact, scientific chronicles have been reporting the presence of plastics in seabirds for the last 50 years. What has changed, however, is how often plastic is found inside them and in what quantity. 

‘In the 1960s, five per cent of studies reported plastic in the guts of seabirds,’ explains Erik Van Sebille, oceanographer and lecturer at Imperial College London. ‘That has vastly increased to 80 per cent of seabirds today.’

By plotting these historical reports over time, a team from the Commonwealth Scientific and Industrial Research Organisation (CSIRO) has predicted that 99 per cent of seabirds will be ingesting plastics by 2050, if current trends continue.  

The plastic that most endangers birds, however, is closer than often thought and sits relatively near to the coast. While the floating ‘garbage dump’ gyres in the middle of the Indian, Atlantic and Pacific Oceans pose environmental issues, they are less dangerous to seabirds simply because they are so far from land-bound nesting sites.

Scientist Britta Denise Hardesty with plastic dissected from the dead flesh-footed shearwater at her feet. After dissection, the amount of plastic in the bird filled her hands, and includes a doll arm, balloon ties, beverage lids and a variety of other fragments. The plastic made up eight per cent of the bird’s bodyweight (Image: Britta Denise Hardesty)

‘In some ways, the ocean currents are helping us by sweeping away all these plastics to the gyre areas where there is the least birdlife,’ says Sebille. If we were to stop polluting tomorrow, these garbage dumps would remain for decades but the coastal areas would clean themselves up pretty quickly for seabirds. ‘Luckily for us, the birds are eating in areas where the plastic is just passing through – places that are much easier to clear,’ says Sebille.

While the impact of the plastic is still largely unknown, it could be affecting their ability to feel hunger. ‘Some birds we’ve found have [the equivalent of] eight per cent of their body mass made up of plastics,’ says Sebille. ‘To a grown man, that’s the weight of two fat house cats that they are carrying around.’ For seabirds, the extra mass is not just an inconvenience as flight is vital to their survival.