Catch That Bat! (8 page)

Chapter 7

The next day was a Saturday. Tom and Sophie leapt out of bed and rushed across to their grandad’s barge. Grandad was already up, whistling a Beatles song and frying eggs.

‘She’s in the darkroom,’ he said, ‘ready for her breakfast.’

Tom and Sophie went into the darkroom and turned on the red safe light that Grandad used when he was developing his pictures. This meant that they could see what they were doing, but Pat wouldn’t be disturbed by the brightness. The children took turns feeding Pat milk and mealworms.

Half an hour later, Mrs Nightingale arrived. She put on a pair of black gloves and inspected Pat’s fur, wings and claws.

‘She damaged her left wing very slightly in the fall,’ she said. ‘We’ll rub this cream on it for the next couple of days to speed up the healing.’

Mrs Nightingale placed a blob of cream on the end of her right glove and then rubbed it into Pat’s wing.

‘Is she in pain?’ Sophie asked.

‘No, not really. But best to be on the safe side. Those mealworms are building her strength up too,’ Mrs Nightingale said.

For the rest of the day, Tom and Sophie continued to sit in the darkroom with Pat, feeding her and changing her bedding.

In the middle of the afternoon, Terry’s head appeared around the darkroom door.

‘How’s she doing?’ Terry asked.

‘Fine,’ Tom and Sophie both said.

Terry looked from Tom to Sophie and said, ‘You know, we WILL have to return her to the wild at some point.’

‘All right. We know,’ Tom said.

‘But in a way, that is almost as cool as looking after her,’ said Terry.

‘What do you mean?’ asked Sophie.

‘Well, we’ve got a mission now,’ Terry said. ‘We’ve got to try to find Pat’s mum.’

‘What? So she can just drop Pat on her head again!’ huffed Tom, folding his arms.

‘Pat’s mum didn’t mean to drop her,’ said Terry. ‘She’ll be worried.’

‘But HOW can we find her mum?’ said Sophie. ‘I read yesterday that there are over a million bats in the UK.’

‘And didn’t you say she was on her way to a new roost,’ said Tom. ‘She could be in Scotland by now.’

‘Not likely,’ said Terry. ‘My bet is they flew off to a temporary roost because of the bad weather last week. It got too damp for them. But they won’t be far away. And what’s more, they might go back to their original roost now it’s drying off.’

‘So that narrows it down to a few thousand bats then,’ said Sophie.

‘It wouldn’t be a mission if it was easy,’ said Terry.

He beckoned them into the kitchen. Lying open on the kitchen table was a large bag containing a black rectangular box with a digital display, a net, a rolled-up sheet of canvas, a small laptop, three torches, a thermos flask, a plastic stick and a gigantic bar of chocolate.

‘My bat-finding bag,’ announced Terry.

‘Do bats like chocolate then?’ Tom asked.

‘No, the chocolate is for me,’ Terry said. ‘Finding bats is hungry work. So – are you up for it?’

Sophie glanced back at the darkroom and hesitated.

Tom took the black box out of Terry’s bag and said, ‘What’s this?’

‘A bat detector,’ said Terry.

‘Then I’m definitely up for it!’ Tom said, turning the box over in his hands.

Sophie was still looking back at the darkroom. Terry noticed this and said, ‘Don’t worry, I’m not suggesting we return Pat to her mother right away. Her wing needs to heal first. But it’ll help if we know roughly where her home is.’

Sophie nodded firmly. ‘OK. When do we set off?’

‘Tonight at seven,’ Terry said. ‘I’ve cleared it with your mum and dad. We’ll start off where you found Pat and work from there.’

So that evening at seven, Tom and Sophie said goodnight to Pat. They moved her on to the kitchen table and switched all the lights on, then watched her close her eyes and snuggle into a corner of the box.

Terry arrived shortly afterwards. A few minutes later, Tom and Sophie found themselves crouching down by the side of the canal, at the exact same spot where they had found Pat.

Terry was standing over them, with his bat-finding kit slung over his shoulder.

‘Pat’s mum probably flew from that bridge right over there,’ explained Sophie, ‘then headed towards those trees behind the canal.’

‘Hmm,’ said Terry, looking at the sky overhead. It was dusk and a few families of bats had started to gather. ‘Let’s see what we’ve got here.’

He took out his bat detector and pointed it at the sky.

‘What’s that actually doing?’ Tom whispered.

‘Well, the human ear isn’t great at picking up bat squeaks,’ said Terry, ‘so this is going to help us. Let’s all be nice and quiet.’

Terry twiddled a knob on the front of his bat detector. Within a few seconds, Tom and Sophie heard a strange squelching noise.

‘Gotcha,’ said Terry. He turned the knob very slightly to the right and the squelching noise got louder.

‘What’s going on?’ asked Sophie.

‘I started by setting the detector at about 45 kilohertz, because I know that the bats around here make noises at about that frequency,’ said Terry. ‘Then when I picked up a noise, I adjusted the frequency to make the sound clearer. It’s like when you tune a radio.’

‘It doesn’t sound very much like a bat,’ said Tom, pointing at the detector.

They listened again to the squelching noise.

Terry smiled. ‘The bat detector slows the noise down so we can actually hear it.’

‘So do you know which type of bat is making that noise?’ Sophie asked.

Terry nodded and sighed. ‘Pipistrelles. Not Daubenton’s, I’m afraid. Pat’s mum ain’t here.’

He switched off the bat detector.

‘I was hoping for first time lucky,’ he said, ‘but never mind. OK, let’s go and find some more bats. Where do you suggest we try next?’

‘Erm, well there are so many around here . . .’ Sophie said.

‘I’ve been . . . I, er . . . well, I’ve started drawing a map . . .’ Tom said. He pulled out a piece of paper from his back pocket and unfolded it to show Terry a map with a cross wherever he and Sophie had already spotted bats.

‘This. Is. Brilliant,’ Terry said. ‘We’ll find Pat’s mum before you can say Small Asian Sheath-Tailed Bat.’

They jogged along the towpath to the first cross on Tom’s map. Terry held up his bat detector and turned the knob on the front until he had picked up a bat’s call. It made a very faint crackling noise.

‘Wow, brown long-eared bats,’ said Terry, ‘one of my favourite species. Didn’t realise there were any around here.’

‘I couldn’t hear anything,’ Tom said, looking up.

‘That’s cos they’re the quietest bats in the UK,’ said Terry. ‘Their shrieks are almost silent. They don’t have to be loud because their ears are so huge. Like – three times the size of their head. With such big ears, they can hear everything – for example, beetles crawling on leaves. And when a brown long-eared bat is resting, his ears are so big that he’ll actually put them away. Either he’ll roll them up behind his head or tuck them under his wings.’

‘That’s so cool,’ said Sophie, chuckling.

Tom looked impressed, but then his face fell. ‘So Pat’s mum isn’t up there?’

Terry shook his head. ‘No, we need to keep looking.’

They walked along the canal and stopped at the next X on Tom’s map.

Terry held up the detector. ‘Want to try?’ he asked.

‘Definitely,’ Tom said, before Sophie had even opened her mouth.

‘OK, turn this dial here slowly until you hear a noise,’ Terry said.

‘There are definitely bats here,’ said Sophie. ‘I can hear them without that.’

Tom and Sophie peered up into the dark trees overhead. Tom kept turning the dial on the detector.

‘I can’t hear anything,’ said Terry, ‘but the fact that you can means they must be a fairly loud species. Maybe noctules.’

Tom twisted the dial on the detector until it emitted a series of loud pinging noises. He grinned in triumph.

‘And there they are,’ said Terry. ‘Noctules. Oh, I love noctules.’

‘It sounds like a laser gun in a science fiction film,’ said Tom.

‘Or someone twanging a rubber band,’ said Sophie.

‘Beautiful, aren’t they?’ said Terry. ‘Let me have the detector a minute.’

Tom handed it back and Terry quickly connected it to his laptop. ‘Noctules are a big, loud bat. Fast too, about fifty kilometres an hour. And tough – they can survive without food for three or four months if necessary.’

He clicked an icon on his laptop and a series of sound waves rippled across the screen.

‘Look, see how the sound waves are getting closer together,’ said Terry, pointing at the screen. ‘That means he’s increasing the frequency of his call. He’s heard an insect. He’s hunting.’

The bat detector was making higher and faster noises and the sound waves on the screen were getting closer and closer together.

‘What’s happening now?’ Sophie asked.

‘He’s closing in,’ said Terry.

The sound waves were almost on top of each other. Then they smoothed out and there was a series of sharp clicking noises.

‘Now what?’ Tom asked.

There was another clicking noise.

‘He’s eating his dinner,’ said Terry.

The sound waves were getting smaller and flattening out.

‘And now he’s flying out of range,’ said Terry.

Tom stared at the screen for a few seconds and then said, ‘So what would Pat’s mum sound like?’

Terry looked at Tom and smiled. ‘Good question.’ He opened a file on his computer and double-clicked it. ‘Like this.’

Tom and Sophie heard a rapid fluttering noise. The sound waves on the screen were bunched together very tightly.

‘It’s like a bird flapping its wings really quickly,’ said Sophie.

‘Or if you hold a plastic ruler over a desk and flick the end,’ said Tom.

‘OK,’ Sophie said. ‘Now we know what we’re listening for. On with the mission.’

Terry nodded. He handed the bat detector to Sophie. ‘Your turn.’

Sophie smiled and took the detector.

For the next hour, they continued to search up and down the towpath, leaving the marina to hunt along the canal at Camden and Islington. Using the bat detector, they picked up more Common Pipistrelles, long-eared bats and noctules. Behind Regent’s Park, they heard a serotine bat, which made a call that was similar to a noctule’s but slower and less metallic.

They were having so much fun, they almost forgot about their mission.

Then at half past eight, Terry said, ‘OK, I’ve got to get you two home now.’

‘But . . . but . . . we haven’t found any Daubenton’s yet!’ protested Tom.

‘And there are loads of places we haven’t looked,’ added Sophie.

‘Look, if I don’t get you back at a decent time, your mum will kill me,’ Terry said. ‘And if she kills me, our mission will be over, won’t it?’