Seabirds in the Pacific are using plastic to build nests
As brown boobies incorporate materials they find in the environment into their nests, research has found that the birds can act as indicators of the extent of plastic pollution in the tropics.
We know that marine debris has become pervasive over the last few decades. From chunks of polystyrene on ice floes in the Arctic to a plastic bag found at the bottom of the Mariana Trench, nowhere has been left untouched by human waste.
But assessing the real scale of the problem over vast tracts of
One way to overcome this is to look at wide-ranging marine organisms that can act as
In a new study published in Marine Pollution Bulletin, researchers from both the University of Tasmania and the Museum have studied the amount of plastic found in brown booby nests right across their range from the western coast of Australia to the eastern coast of Brazil.
They found that when plastic debris is available to use as a nesting material, the birds will invariably use it, supporting the case for using them as indicator species.
Sentinels of the ocean
In the northern
In the southern hemisphere, however, things aren't as straightforward.
'Brown boobies nest across the South Pacific, the Caribbean and the South Atlantic. So we wondered whether these could be some sort of indicator of the extent of ocean plastic.'
The birds build little nests on the ground in colonies, often along beaches.
'We noticed back in 2014 that quite a lot of booby nests had plastic in them,' says Alex. 'From fishing rope
This led the University of Tasmania's Megan Grant to investigate whether the nesting material of the boobies could be used as an indication of the local extent of marine plastic.
Megan collected data on the amount and type of debris found in the boobies' nests from 18 different locations right across the birds breeding range. She could then compare what was found in the nests to the amount and type of debris found washed up on the adjacent beaches.
'The nesting material typically derives locally, so boobies will get their material from the beaches they nest on or very close offshore,' explains Alex, 'and what we found was really interesting.
But that isn't the whole story.
When the team compared what debris was found on the beaches to what the birds were using as nesting material, there was only a slight overlap. This suggests that the boobies had their preferences.
'It wasn't consistent across all the sites,' says Alex. 'Some colonies preferred green ropes, others white fragments. That variation among the sites is one of the more fascinating aspects.'
What might be driving this variation is still not really understood. For some seabirds in the
The plastic problem
It will come as no surprise that the plastic problem pervading the oceans is becoming more visible and more dangerous to marine life.
'In the worst case scenario, birds using plastic to build nests can lead to entanglement,' says Alex. 'In the UK, for example, we see gannet chicks getting caught and then dying. This is either through being tangled and falling off the nest or getting strangled.'
While for the brown boobies the impact of building their basic nests with plastic might not be so great, these birds are yet another indication that we are rapidly changing the oceans and need to do something about it soon to prevent the further loss of species.