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Rise of the shearwater

  • Written by  Hazel Southam
  • Published in Wildlife
Rise of the shearwater Clare Kendall
26 Nov
2015
Once a common sea bird on the Isles of Scilly, by the start of 2014 Manx shearwaters were on the verge of extinction due to a rodent invasion. But dedicated conservationists and some rat poison can go a long way

I’m lying on tussocky grass carpeted in pink-flowering thrift on the island of Gugh in the Scilly Isles, with my ear to a rabbit hole listening out for any evidence of the Manx shearwater, a rare, ground-nesting sea bird that shares burrows with the bunnies.

An eerie, rasping, throaty call comes repeatedly up the long burrow, telling me that I am not welcome, the avian equivalent of shouting at me to go away or they’ll call the police.

It’s great news to be shouted at by a Manx shearwater. A few years ago there weren’t many of these rare birds left. But a concerted effort to kill brown rats across the islands has led to a resurgence in shearwater numbers, and has seen the first chicks fledge in an estimated 100 years.

CK-SCILLY63A Manx shearwater chick (Image: Clare Kendall)

Rat Tales

There is archaeological evidence of Manx shearwaters inhabiting the Isles of Scilly – which lie just 28 miles off the Cornish coast – dating back to 2000BC.

By the 13th century, they were so common that they were used as currency. Annual rents were paid in 30 ‘pufons’ (either puffins or shearwaters) to the Duchy of Cornwall.

Everything carried on just fine, until the accidental introduction of the brown rat in the 17th century, thought to have arrived on many of the shipwrecks that dot these treacherous waters.

Because Manx shearwaters live in burrows and raise just one chick each year, their eggs and chicks were easy prey to the incoming rats. Numbers plummeted, so much so that by  2006 there were just 171 nesting pairs on the entire Isles of Scilly. And the numbers continued to drop, because of the rats until, by 2014, there were just 24 nesting pairs left. A chick hadn’t successfully fledged in living memory.

GMCK-MANX1A ‘raft’ of shearwaters taking flight (Image: Clare Kendall)

Rising Up

To combat this situation, a £750,000 scheme was set up in Scilly to save the Manx shearwaters. The aim was to rid the islands of St Agnes and Gugh of the rodents. This would protect not just the birds on those two islands, but also provide a rat-free buffer to the uninhabited island of Annet, which is a haven for seabirds.

And it appears to be working. Last year, 52 pairs of Manx shearwaters nested and ten chicks fledged successfully. Twenty-eight have fledged so far in 2015 and volunteers are still trying to count the number of the resurgent birds across the three islands. It’s hoped that they will ultimately see a 50-100 per cent increase. It’s having a knock-on effect for other species as well. Three storm petrels have also fledged – the others were getting eaten by the rats as well.

‘I was so emotional last year when they had the chicks,’ says Peter Exley, the RSPB’s public affairs manager for the southwest of England, who helped set up the project. ‘It was a rare moment. Conservation is a long, hard slog. But this was a peachy moment when you feel you have done something.’

GMCK-MANX23Jaclyn Pearson inspects a Manx’s burrow (Image: Clare Kendall)

Changing Patterns

There are an estimated 280,000 Manx shearwaters in the world, and Britain acts as a home to the majority of them during summer months.

They are astonishing fliers, doing a round-trip migration of some 20,000 miles. The parents feed their chick up to above flying weight and then head off for Argentina, leaving the chick in the burrow. While still here, it flaps its wings and gazes at the stars. It’s thought this is how it fixes the position of its burrow to which it will return year after year.

‘It’s an amazing bird,’ says Exley. ‘Their migration is phenomenal. They pair bond for life. Everything about them is remarkable. Yet the one thing that they couldn’t cope with was predators. It’s important that they are here as they are part of the islands’ history and legacy. It would be terrible if the kids here didn’t have them. That wouldn’t be much of a legacy, would it?’

Jaclyn Pearson from the Seabird Recovery Project and her gang of volunteers have changed all that.

In 2013, Pearson started talking to the 84 locals on St Agnes and Gugh about the plight of the shearwater. She got them on side and then asked for their help in creating a less attractive environment for rats.

Farmers cleaned out sheds and barns and made changes in how feed was stored. New, sturdy refuse bins were supplied to every household and islanders started taking waste to the local tip just once a week.

All 11 children at the school on St Agnes were taught about rats and shearwaters. Then, for three weeks in November 2013, more than 1,000 baiting boxes were laced with poison. As a result, some 3,300 rats were killed.

GMCK-MANX39Local schoolchildren learn about the shearwater’s plight (Image: Clare Kendall)

Rat Calls

Pearson has also set up a ‘Rat on a Rat’ emergency phone line. If anyone thinks they’ve seen a rat, they call the number posted in pubs and noticeboards. Volunteers then head out and set up a grid of bait boxes laced with nothing more menacing than chocolate-flavoured wax. These are checked daily for footprints left in ink and for the tell-tale tooth marks.

Nicky Anderson runs The Turk’s Head pub by the quay on St Agnes. ‘Rat on a rat’ stickers are on the bar, and she’s put up noticeboard to keep people up to date with what’s happening to the Manx shearwaters.

‘I was a bit concerned that we’d see lots of unhappy rats dying,’ she says. ‘But it just went silent. My cat Fred used to be a great hunter, now he’s gotten fat. But I can go up into the loft or to the compost without worrying about rats. The only rats I see are fake ones. People keep sending them to me to display in the pub!’

Increasingly, calls to the ‘rat line’ are false alarms and the islands hope to be declared officially rat-free in January 2016.

‘We inadvertently introduced the rat,’ says Pearson, ‘so we have to put it right. We’re not just doing this for the species locally, or nationally, but we have an international responsibility because of the numbers here. The rats were just in the wrong place on the islands.’

GMCK-MANX35A ‘Rat on a Rat’ sticker in the local pub (Image: Clare Kendall)

Bird watching

It’s evening, and I’m heading out on a Manx shearwater-spotting boat trip with local ornithologist Will Wagstaff. A few years ago there wouldn’t have been much point. Now it’s a very different story.

The shearwaters foregather on the water before heading in to their burrows as close to dusk as possible. They’ve spent a day or more fishing at sea and are full of food for their young. But, if they head to their burrows individually, they are likely to be mobbed by gulls in a bid to get them to regurgitate their food.

To avoid this fate, they meet up in groups, known as rafts, and then head into their burrows just as the sun is setting over the Western Isles.

We bob about spotting puffins, razorbills, guillemots and even a crane that’s taken up residence on Annet. Suddenly, they’re there. A raft of around 50 to 60 Manx shearwaters. They fly low over the waves and dip down to rest repeatedly. Birders clad in sturdy outdoor clothing rush to the side of the boat to spot them as they wheel and turn.

Boatman John Peacock advises his customers not to ‘panic’ if they see a rat. ‘The team will spring into action,’ he says, proud of what’s been achieved. ‘It’s a really, really big success story. There are big numbers of razorbills and guillemots now too. They’ve all benefited. It was a really big undertaking, but I feel really good about it. I’m seeing more and more birds on the boat now.’

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