The hills on Rum are said to be home to trolls. I like to imagine them to be small, almost rock-like, covered in moss with beady eyes and long, folded ears. But perhaps they’re larger, more grotesque and a murkish green, dragging their feet and hunching their shoulders.

What I can picture is the noise they make. An otherworldly screech, almost guttural, that echoes across the cliff edges and through the gaps in the trees. There may be just one at first, then another, and soon, it is a discordant chorus.

That’s the sound the Vikings were said to have heard back in the 11th century, and where one of Rum’s tallest hills, Trollival, got its name. The strangled, eerie cries were just as present back then as they are now, and one of Rum’s most fascinating myths was born.

But of course, we know where these sounds come from now, and they’ve started sounding in the hills once again.

The Manx Shearwater is an odd little bird. It is small, with black and white wings and a long, long migration route. And Rum is home to 120,000 breeding pairs of them. They make their nests in the ragged cliffs of Rum’s stunning hills; Hallival, Askival, Barkeval and Trollival. In a few weeks time, we’ll be heading out onto the reserve, sticking our hands into tiny........

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