‘Come left a little.’ They all shuffled leftwards a few feet and the new angle better revealed a small bird the size of a swift, roosting upon the scant nest, sitting tight between the stones. Its feathers were bluish-grey with white upper tail-coverts and a small dusky black bill.

The bird ruffled its wings, twitching as if sensing their scrutiny.

The earl inhaled sharply. They had all seen, in the movement, the bright ovoid perfection of its egg. ‘Tell me what you know of them,’ he whispered.

Effie considered for a moment. She knew a lot. Her books were the only distraction to be had on long winter nights, and if it was a choice between that and the Bible . . . ‘They’re pelagic, spending up to eight months at sea. Their forked tails make them good divers. They’re slightly larger than the Stormies, with an erratic, hesitant flight pattern. They often appear to walk on the water . . . What else?’ She thought harder. ‘Oh. Yes. They don’t recognize their own chicks and will switch mates if a hatching fails. They usually only lay one egg. It’s rough-textured, chalky white with a few small red dots at the larger end and they’re highly prized.’

‘I’ll say,’ Sholto murmured, glancing at her. ‘Papa’s been after one for six years. And you’ve just walked him straight up to one!’

‘I’m afraid I really must have it,’ the earl murmured, as if he was breaking bad news to her. But he wasn’t the first rich man to have arrived here on an egg hunt and he wouldn’t be the last. ‘Sholto, seeing as you’re nearer . . .’

His son nodded.

‘Wait,’ Effie said as he moved to go forward. ‘If you invade the nest, they’ll spit oil on you.’

‘That’s nothing to what Papa will do if I don’t get it for him.’ Lord Sholto gave a bemused smile.

It was the sort of smile that probably meant he always got what he wanted but she held firm. ‘Just wait. She’ll move.’

‘Today?’ But it was a gentle joke, and he moved back into position again.

‘During incubation, both parents frequently abandon the egg for days at a time. Their eggs incubate at much lower temperatures than other birds. Look, see how she’s twitching again. I think she’s getting ready to fly . . .’

‘How do you know all this?’ Lord Sholto asked.

She felt offended he expected so little from her. Did he assume her to be primitive just because she was an islander? ‘I watch and I learn, sir.’