‘Thanks, I’ll be quick.’ Clasping her camera, the girl hurried off as Tilly made her way around the back. Luke went straight indoors, and when she rejoined him half an hour later, he was paging through Native Mammals of the North. He glanced up at her arrival. ‘Come and see. Do you reckon this is the bat we saw, Tilly? Far as I can tell the colour’s the same, though if there’s a difference it could be age related. And the nose is definitely the same . . . What d’you think?’

She scrutinised the picture, trying to recall the exact shape of the little mammal viewed in the faint daylight at the mouth of the cave. ‘It looks about right. They’re all the same though, aren’t they – only bigger or smaller? It was tiny so it might’ve been a baby.’

He sighed. ‘There are thirty-odd species so no, they aren’t all the same. And it wasn’t a baby, not if I’m right. I’ll have to wait for the film to be developed to be certain, but I’m pretty sure this is the one.’ He tapped the picture. ‘Which makes it a leaf-nosed bat.’

‘So? I thought it had a weird-looking face, but I’ve never seen one up that close before,’ Tilly admitted.

Luke tutted. ‘You need to study the native species,’ he said seriously. ‘It’s part of the job, Tilly. And if I’m right, that cave is rather special because the leaf-nosed bat has only ever been found in Arnhem Land. Which would make this one a separate colony and maybe different. A new species, in fact.’

‘Really? Wow! You’ll be famous, Luke, if you’re right. We’ll have naturalists from all over swarming the place, wanting to see and study . . .’ Her thoughts leapt ahead, dismissing caution. ‘And once the WPA hears it’ll be bound to guarantee the Sandstone project, wouldn’t you think?’

‘Maybe,’ he said cautiously. ‘If I’m right. But it would also mean they’re very rare – maybe the only colony in existence – so they’d need protection. The first thing I’d be advising would be a gate to keep them safe. To keep people out. It’s not like they have a choice of habitat round here if they’re chased out of their home. Theirs is the only cave in the region.’

‘Have you told Sophie?’

‘Not yet. She’s feeding the joeys, and I wanted to check the books and your recollection first.’

‘Well, I’m sorry I can’t be more help, but you probably are right. It pains me to admit how often that happens.’ He grinned at that and she said, ‘Congratulations if it’s true. And now I’m bagging the bathroom.’