‘Well, we didn’t do a lot of sleeping.’ Hugh stopped and looked down over the island. They could see each of the croft houses, set out like a child’s drawing. The clarity of the light made the perspective look wrong. Everything was flat and too close. Hugh took out another cigarette, the only sign that he might be nervous. ‘How did you know?’

‘Someone told me Angela liked pretty boys.’

‘She picked me up the first night I was here.’ Hugh had a smile, wide and welcoming, but fixed; there was somehow, even when he was talking, a shadow behind the words. It gave Perez the sense that he would take nothing seriously. ‘I was last up in the common room. I’d been drinking all evening. I’d wanted to visit since I first heard about the Fair Isle field centre; it was so cool to be there finally. I felt like celebrating. And Angela wandered through from the flat and found me there. “Let me give you a tour of the island.” It was a clear, still night, just before the westerlies started. Cold. There was ice on the windscreen. Unusual so early in the year, apparently. She took me up to the west cliffs and pointed out the lights of Foula right in the distance.’

‘You had sex?’

‘Twice that night. Once in the back of the Land Rover, parked on the airstrip, and once in an empty room in the North Light when we got back. It was three in the morning when she left me.’ He paused, added with admiration: ‘She was up at dawn to do the trap round.’

‘And on other occasions?’

‘Not every night. She’d made it quite clear we met up on her terms. She’d come and find me when she wanted me.’ Hugh spoke without apparent resentment. He wasn’t like Perez with his first lover; it seemed Hugh had no interest in forming a permanent relationship. The smile remained in place.

They’d reached the peak of a ridge and now had a view north. The only sign of habitation from here was the lighthouse and that was almost obscured by a fold in the land; only the tower and the lens were visible. Perez remembered when the lighthouse was manned: there’d been a Glaswegian couple with a little boy who’d come to the island school, a bluff retired merchant seaman as senior keeper and they’d all lived in the whitewashed buildings at the foot of the tower. Then the field centre trust had taken it over, raised the money to convert it. From this position he became aware again of how isolated it was.

‘Did she come to find you?’ Perez asked.

‘Oh, yes. At odd times. Once in the middle of the day when everyone else was having lunch. We were in the dorm. Dougie could have come in at any time. But that was what she liked. The excitement. The danger.’

And you? Perez wanted to ask. Did you like it too?

But he could see that Hugh would have found the question ridiculous. Of course he liked it. Sex without complications. Wasn’t that the dream of every young man? And why shouldn’t a woman enjoy it too? Perez would have liked to discuss Angela’s attitude to men with Fran. He suspected Fran would accept it without question. Very little shocked her. He found Angela’s need for pretty boys not so much shocking as depressing. What did it say about her marriage? That it bored her? That she had to find her excitement elsewhere? Did that make Perez boring too, with his plans for marriage, a settled family? Would Fran think him tedious after a couple of years?

Now they were both out of breath and they stopped. Perez took a flask of coffee from a small backpack and handed Hugh a slice of the sticky chocolate concoction that the islanders called peat. His mother had made a batch the evening before. They sat on a flat rock that stuck out of the heather, looked down on the bright blue sea and the wild white waves.

‘Did Angela talk to you?’ Perez asked.

‘Of course we talked.’ Hugh regarded Perez with patronizing amusement. ‘We got on. We were good mates.’

‘You didn’t seem very upset by her death.’

Hugh shrugged. ‘To be honest, it was never going to be a long-term thing, was it? I mean, I can’t imagine we’d have kept in touch once I’d left the Isle. I’m sorry she’s dead, but I can’t pretend to be devastated. I can’t bear shallow sentimentality.’

Perez wondered if that was what he was. Sentimental and shallow. A brief affair followed by no contact didn’t fit his definition of being a good mate.

‘Did she seem anxious about anything? Concerned for her own safety?’

Perez had expected an immediate flip remark, but Hugh considered the question. ‘Something was bugging her,’ he said eventually. ‘The last couple of days she’d seemed tense, not her usual self.’

‘What was the problem?’

‘She wouldn’t talk about it,’ Hugh said. ‘Told me it was none of my business. That was OK with me. I didn’t want to pry. I thought the weather was getting her down. The lack of good birds. Or Poppy. The girl really got under her skin.’

‘Did she discuss her husband with you?’ Perez looked out over the blustery water. The air was so clear that he could see Shetland mainland, the outline quite sharp on the horizon, the first time it had been visible since they’d arrived on the island. He found the sight reassuring, a connection at last with the outside world. The next day the boat would go out and Vicki Hewitt and Sandy Wilson would come back in with it. He would no longer be working alone.

‘Oh, Maurice wasn’t bothering her,’ Hugh said with a little laugh. ‘Maurice would let her do whatever she wanted as long as she stayed married to him.’

‘He knew about her affairs?’

‘Probably. Or didn’t look too hard at what she was doing because he didn’t want to know. As I said, she resented Poppy being here. I think it was the first time Maurice had ever stood up to her. Angela had said the autumn was a bad time for the girl to visit – after the seabird ringing it was her busiest time. He’d insisted, said his daughter had to come first for a change. Angela was shocked. She usually got her way. But I’m not sure that was what was worrying her. It was only temporary, after all. Eventually the wind would change and the girl would get out.’

Hugh stood up and brushed the crumbs from his jacket. ‘I thought you wanted to see this swan.’ He turned on the inevitable smile and walked very quickly down the bank towards Golden Water. Perez had almost to run to catch up with him.

The swan was on a shingle beach at the side of the pool. It looked to Perez like any of the swans that came into the island in long skeins in the winter. ‘Show me what all the fuss is about,’ he said again.

Hugh set up his telescope on a tripod and let Perez look. ‘It’s the black beak that’s important. That and the American ring, which proves it hasn’t escaped from a collection somewhere.’ He straightened. ‘There’ll be hundreds of birders in Shetland mainland waiting to come here to see it.’

Perez had a sudden image of an invading army preparing for battle. How would a sudden influx of visitors affect the investigation into Angela Moore’s murder? And was there anything he could do to prevent it?

‘Will folk really go to all that effort?’

‘Believe me,’ Hugh said. ‘People would kill to get that bird on their list.’

Chapter Eighteen