Bat Detective arrives in Japan, our next World Tour stop

Welcome to the latest stop on our World Tour! We’re now in Japan, after spending the last two months uploading data from Australia and New Zealand to the Bat Detective site. Firstly, a massive thanks from the Bat Detective team for all your efforts in listening to and classifying our data so far this year – thanks to the amazing efforts of citizen scientists during the World Tour as well as British Science Week back in March, we’ve got a much larger dataset of labelled bat calls to train our automated algorithms with, and the results are improving.

In the coming months we have a few more World Tour stops before we reach the end of our global bat search. This month we’re in Japan, with a new set of data uploaded to the Bat Detective site that was recorded on car-driven transects during 2010 and 2011 in locations throughout Japan: you can see where the surveys were carried out on the map shown below. We hope you’ll enjoy searching for bats in Japan, and if you have any queries just let us know via the Talk section of the Bat Detective website.

For this month’s blog post, to accompany our Japan data, we’re publishing a short piece written by iBats and Bat Detective’s founder Kate Jones during her 2010 trip to Japan, during which she collected iBats audio data and hosted training workshops for the iBats monitoring program. Scroll down below the map to start reading…


Locations throughout Japan where the data currently hosted on Bat Detective were recorded, during 2010 and 2011.

“I stare slightly queasily down at the tiny but perfectly formed green-tea plantations and rice paddies in the valley far below, as the car winds down the narrow mountain roads of the Mount Fuji highlands in Japan. We stop to try to manoeuvre around an impossibly large truck loaded with locals, and I am struck by the beauty of the mountains surrounding us, lush green forested slopes and azure blue lakes matching the skies overhead.

A crazy expansion of the iBats monitoring program over the past few months has me visiting places and people that I have only imagined. ‘What are you doing in Japan?’ asked the Japanese air attendant politely as I waited for the bathroom on my 11 hr flight to Tokyo. ‘I am hoping to develop a program with local people and scientists to monitor bat populations’, I replied carefully. ‘You see, you can use changes in bat populations like a heart monitor to check the health of nature and the impact of people on the environment’. ‘Bats?’ she squealed, ‘I LOVE bats,’ and proceeded to draw me a map of Japan marked with large crosses where I should visit to see bats. Equally unexpected was finding out at dinner on our first night given by our host, Dai Fukui, that grilled eels are actually very tasty. Especially as tempura with sesame dressing. Yum.

Stuart Parsons, sitting next to me in the car, is looking even more pale than I. Obviously the sake of the previous evening is not going well with Dai’s mountain driving. David Hill on the other hand is made of sterner stuff, alternating between calmly explaining Japanese culture to us in the back and chatting easily to Dai in Japanese in the front. Yesterday was spent exploring caves in the mountains with members of the Japanese bat group (Komori no koui) and listening to horseshoe bats bubbling and warbling over our heads.

In the evening we were introduced to a whole new concept in fieldwork, a ‘mist netting barbecue’. We left the hard work to the local experts and sat around chatting to the group while some of the students brought us mist netted bats for us to look at. The endemic tube-nosed bat (Murina ussuriensis) was especially cute — David’s favorite. Dai explains that he has found this bat hibernating in little tubes it has made in the snow in winter. We drink cold sake and ponder how this bat copes with subzero temperatures. I explain the importance of monitoring to the group and how our acoustic equipment works. Stuart displays the calls in real time from the bats flittering over our heads on his brand new iPad. Whilst outwardly dismissing this gimmick, I am secretly marveling at how Stuart is among the select few in the world that can out-geek me with Apple products.

Although bats are protected in Japan, there is no formalised monitoring of their populations and little general public awareness of the important role bats play in ecosystems. This is a fact that the bat group is trying to change with their awareness-raising activities around Japan every year, culminating in a bat festival in August. The car lurches down the mountain and I see a Bat Conservation Trust sticker on the car in front in our little convoy.

‘Are you a member?’ I ask curiously of the owner, Keiko Osawa, earlier that day, during our lunch overlooking Nagashima Dam. ‘Yes,’ motioning to her husband Yushi, ‘we like getting Bat News’. Yushi is a photographer and they seem to spend most of their time travelling the world photographing fruit bats.

‘Kate San,’ asked the secretary of the bat group Akeiko Mekosa politely. ‘How many members does Bat Conservation Trust have?’. She exclaimed in surprise when I told her over 5000, and said she struggles to get their membership up to 500. The group wants to develop an iBats project here over the next year, and hopes to raise the profile of bats and start its first national monitoring program. Stuart and I are here to help this get started, and to run a workshop on iBats monitoring, volunteer management and acoustic analysis for them.


Ussuri tube-nosed bat, Murina ussuriensis (image reproduced from

Beside me in the car, Stuart is beginning to look more normal and is checking his photos on his new iPad just to annoy me. We chat about his plans for his iBats project in New Zealand next summer (our winter). In contrast to Japan’s forty species of bats, New Zealand only has two. Stuart bristles at my dismissive tone and says that what they lack in numbers they make up in distinctiveness.

I have to agree with him for once — New Zealand is home to the short-tailed bat (Mystacina tuberculata) which spends most of its time in the moist fern-filled forests scampering on the ground hunting for fruit and insects. Although the iBats car-based acoustic monitoring would not be useful to monitor Mystacina as they are confined to deep forest, Stuart sees the potential for using iBats to monitor long-tailed bats (Chalinolobus tuberculatus). He has agreed to trial our new iBats application for the iPhone – you just attach your iPhone to an ultrasound detector and send the recording and GPS information straight to the iBats website. We did a test run in the Fijordland of New Zealand’s South Island in February and apart from us being bitten to death alternatively by sand flies and mosquitoes, it worked perfectly. Long-tailed bats happily flew over the car as we made our way along the transect through Lord Of The Rings country. Stuart is excited about using the technique to better understand the distribution of this threatened endemic species.

We head back up into the clouds with the help of the nice Japanese lady satnav to where we are staying tonight and holding the workshop. The workshop venue is a lodge in the highlands with traditional Japanese style rooms, where the bed is made every night from bedding beautifully folded and organised in wooden cupboards with ornate sliding doors. I’m especially excited about the tales of the Japanese bath houses, with their piping hot plunge pools fed from the surrounding hot springs.

The expansion and interest in the iBats project has been rather overwhelming over the last few months and has seen the team giving workshops in Hungary, Ukraine and most recently Russia, where the vodka flowed a little too easily but the welcome and enthusiasm for the project was amazing. I am overwhelmed by the generosity of the people I have met around the world and their commitment to conserve their bats in the face of conditions much more problematic than those we face. As we stop to investigate the first bat house built in Japan, one of the group asks me where next for the iBats project. Hmmmmm, what about Australia?”

Next World Tour stop, Australia!


Southern free-tailed bat (photo by Terry Reardon, via Adelaide Bat Care)

Welcome to the latest stop on the Bat Detective World Tour! After a month in New Zealand, we’ve reached our next stop, Australia, and we’re now just over halfway through the full tour. We’ve just uploaded a new set of acoustic data to Bat Detective, which was recorded by the iBats project in the Adelaide Hills in 2011. So visit the Bat Detective site now to listen to the data and get searching for Australian bats.

In addition to the World Tour and a busy British Science Week, there’s been lots of activity in the Bat Detective camp in the last few months. In our last blog post we discussed the recently published Mexican bat classification paper by members of our research group, which was widely reported in the BBC and other media.

Following that, this month Bat Detective founder Prof. Kate Jones went out bat detecting on London’s Hampstead Heath with Adam Rutherford, for BBC Radio 4’s weekly science show Inside Science. While listening to the sounds of passing pipistrelles through an ultrasonic detector, they discussed echolocation, the use of acoustics to monitor bat populations, and how with the public’s help we’re building classifier algorithms to improve the effectiveness of bat monitoring both in the UK and globally. You can listen to the programme now, or download it as a podcast, from the BBC Radio 4 site.

And in other recent news, in April our team’s Rory Gibb presented some of the latest findings of Bat Detective’s citizen scientists, as well as our work to develop automated bat call detector software, at the British Bats Research Symposium in London. Stay tuned to the Bat Detective blog in the coming months for further updates about the progress of our research (you can read our last update here) – the efforts you’re putting in to classifying our recordings are making a real difference.

Adelaide Hills, the area where the Australian world tour data were collected

Adelaide Hills, the area where the Australian world tour data were collected

Similarly to the New Zealand audio, our Australian acoustic data are noisier than some of the European and American recordings from earlier in the World Tour: there’s lots more background sound, making it sometimes difficult to distinguish sounds from each other. Keep an ear out for various types of insects, including distinctive rattle-like calls made by crickets and grasshoppers (Orthoptera), as well as calls from a wide variety of bat species.

There are around 14 species of microbat (echolocating bats) found within the Adelaide region. They include the Southern free-tailed bat (Mormopterus planiceps, pictured above), a relative of the well-studied free-tailed bat species found across the Americas, as well as the little forest bat (Vespadelus vulturnus), which is only found in south-eastern Australia and is one of the continent’s tiniest mammals (often weighing less than 4 grams). Also found in the Adelaide area – including in the city itself – are much larger fruit bats such as the grey-headed flying fox (whose population in the area is reportedly growing due to migration from elsewhere in Australia). However, since these do not use ultrasonic echolocation, you won’t be able to hear them in our recordings.

Thanks very much for all your efforts in classifying the New Zealand data, and we hope you’ll enjoy searching for bats in these Australian recordings. As ever, if there’s anything you find that you’re unsure about, just use the Talk section to flag it up and discuss with other members of the Bat Detective community.


Bat Detective New Zealand: our latest World Tour location

Welcome to New Zealand, the latest stop on the Bat Detective World Tour! As of today we’ve just uploaded a new set of audio data to Bat Detective, recorded along survey transects on New Zealand’s South Island. You can see the locations of the surveys on the map below, and visit the Bat Detective site now to get searching for bats.

Prior to this we’ve spent the last month hosting audio data from iBats Mexico, which was neatly timed to coincide with the publication of the latest automated bat call classifier from members of our research group – a classifier for Mexican bat species. As with our results from the algorithms we’re training with Bat Detective data, it’s another example of how advances in machine learning technology are increasingly enabling the development of tools and systems for effective acoustic monitoring of bats (as well as biodiversity more broadly). You can find out more about the Mexican classification tool and how it will assist in bat population monitoring via some great coverage in the media, including in Science and an interview with our group’s Dr. Veronica Zamora-Gutierrez and Prof. Kate Jones on the BBC.


Locations on South Island, New Zealand, where iBats data were recorded

Bats occupy a unique space in the ecology of New Zealand, since they are the country’s only endemic terrestrial mammals – before humans settled the islands, the only mammals native to New Zealand were three bat species (the greater short-tailed bat, lesser short-tailed bat and long-tailed bat) and several species of marine mammal. Since human settlement this has changed, with invasive mammalian predators (such as rats and cats) driving massive declines in the populations of endemic birds and bats. Indeed, the last sighting of the greater short-tailed bat was in 1967, and it is now believed to be extinct, while New Zealand’s other two bat species, the lesser short-tailed (pictured below) and long-tailed bat, have both experienced major declines and are priorities for conservation.

The acoustic data on Bat Detective New Zealand, recorded on South Island in 2010, are much noisier than lots of the recordings you’ll have previously heard on Bat Detective. Many clips have a great deal of background noise and static, in addition to distinctive bats and unique rattling insect calls. Although this can make it challenging to determine what sounds you’re hearing, it’s very useful to include data like these while training algorithms to automatically find bat calls – this will help improve the algorithms’ ability to detect bat echolocation calls in even the most noisy of real-world acoustic recordings. This will make them more useful for surveying bats in naturally noisy and complex acoustic environments, such as urban areas where there is lots of human-generated sound, or highly biodiverse (and therefore very loud) rainforests.

We hope you’ll enjoy helping us search for bats in our New Zealand data, and as ever if you’re struggling to figure out whether a sound is a bat, an insect, or something else, you can use the Talk page to flag it up and discuss it with us and other users.


Lesser short-tailed bat (photo via New Zealand Department of Conservation)


Welcome To Mexico, our latest World Tour location!

Welcome to Mexico! After our exciting hiatus for our British Science Week classifications target (which you helped us to hit comfortably), we’re now back on the road for the next stop on the Bat Detective World Tour. This time we’ve headed south, from our previous location in New York to tropical Mexico. Today we’ve uploaded a new set of data collected in 2008 during audio surveys in several locations on the Yucatán Peninsula, so head across to the Bat Detective site now to begin listening and classifying bat calls.

These data were recorded by a team that included Bat Detective’s founder Prof. Kate Jones, and include surveys around the city of Merida, the capital of Yucatán, as well as the Mayan historical sites Edzná and Calakmul, both of which are located in the jungle and are areas of special archaeological as well as biological interest.

Mexico is a remarkable country in which to search for bats. It has among the highest bat species diversity found anywhere in the world, as well as some of the world’s most unusual, beautiful and bizarre bat species. Some of our favourites are the spectral bat (Vampyrum spectrum), the largest carnivorous bat in the world; the fish-eating bat Myotis vivesi, which hunts by using its exceptionally large feet to snatch marine fish and crustaceans from the sea; and the banana bat (Musonycteris harrisoni), whose extremely long snout and tongue are ideal adaptations for feeding on nectar from tropical flowers – and lend it its alternative name of trumpet-nosed bat. Other Mexican nectar-eating bats are famous as important pollinators of agave plants – vital for making tequila.

Locations on the Yucatan Peninsula, Mexico, where Bat Detective audio data were collected

Locations in Mexico, where Bat Detective audio data were collected

Another of the country’s best-known bats is the Mexican free-tailed bat (pictured below) which is widespread throughout the Americas and famed for roosting in colossal cave colonies of up to several million individuals. Because of its abundance and visibility, it is fairly well studied; for example one 2015 study, published in the journal Science, found that this species has the remarkable ability to produce interference vocalisations to ‘jam’ rival bats’ echolocation sonar, potentially enabling individuals to improve their own hunting success.

In southern Mexico, as in other tropical regions of the world, bats are even harder to survey than in temperate regions – tropical forests are noisy places, filled with inhabitants occupying their own sonic niches and working to be heard above and around each other. Developing automated bat detector softwares to pick out bat calls from this dense acoustic hubbub, and to then identify those calls to the level of species or species group, requires a lot of labelled input data to train our algorithms.

But it’s worth the exploration, since many of the calls you’ll encounter in tropical Mexico are quite unlike our earlier data from temperate regions such as Europe and New York. So if you’re unsure, use the guide underneath the main classify window to help you figure out what sounds you’re hearing. And as ever, if you have any challenges working out whether a call is a bat or not, just click through to discuss it on the Talk section of the site with us and other citizen scientists. These are some of our favourite recordings to be uploaded to Bat Detective, and we hope you’ll enjoy listening and classifying them too.


Mexican free-tailed bats (photo via Wikimedia Commons)

British Science Week: we did it!


Yesterday was the final day of British Science Week – and we’re now very happy to report that with your amazing help we sailed past our target of 100,000 new classifications over the course of the week. We reached the target on Friday night (to much excitement), and then classifications continued to climb over the weekend – reaching a total of over 110,000! The Bat Detective team would like to extend a huge thank you to all the citizen scientists who participated and contributed their time and energy over the course of the week – your efforts are much appreciated and will make a real difference to our research.

Keep an eye on the Bat Detective blog, Twitter and Facebook during the coming months, and we’ll keep you updated about how our research is going, and explain how your classifications during British Science Week are helping to improve our automated bat detection algorithms for bat population monitoring.

We’d also like to extend our thanks to everyone at British Science Week and the Zooniverse team, as well as everyone who’s been involved in the last week’s bat-themed events, including the Grant Museum, In The Dark Radio, Bat Conservation Trust and all the speakers at the Museum’s bat-themed lunchtime talks.

After that exciting week’s diversion, the Bat Detective team are now preparing to resume our World Tour where we left off – next stop Mexico! We’re preparing to upload some new Mexican data to the Bat Detective site so stay tuned over the next couple of days – hopefully you’ll be keen to continue helping us in our search for bats.


British Science Week and Bat Detective: get involved!


British Science Week 2016 begins this Friday! This year’s citizen science theme is “all things bat-related”, and if you’ve been following us on social media you might have noticed that we’re excited to be one of the week’s main citizen science partners. With the help of both our fantastic current community of citizen scientists and what we hope will be many new recruits, we’ve set ourselves the goal of reaching 100,000 new classifications over the course of British Science Week.

So from Friday 11th March to Sunday 20th March we’re asking for your assistance in helping us to hit our target, by listening for for bats, insects and other sounds on Bat Detective. An extra 100,000 classifications will give us a fantastic boost in useable data for our bat detection algorithms, and will be a great step towards our goal of producing new software for bat population monitoring. We’ll have a counter on the Bat Detective site throughout the week, counting up the number of classifications we’ve managed so far and reminding us of how far we’ve yet to go. So please do get involved during the week and help us reach our goal — your efforts are very much appreciated and are invaluable to our research. To get involved, head to the Bat Detective website at any time and click “Get Searching”.

In addition to aiming for this classification target, we’ve also got a week of special bat-related events planned in collaboration with British Science Week and the Grant Museum of Zoology.

These will be taking place throughout next week at the Grant Museum on Gower Street, London, just around the corner from where the Bat Detective team are based at UCL. Throughout the week, from Saturday 12th to Saturday 19th March, the Museum will be hosting a pop-up Bat Detective stand where people can participate, classify calls and help us reach our target. The week’s events will also include lunchtime talks from researchers from Bat Detective and the Bat Conservation Trust, a special immersive audio evening exploring bat echolocation, and a family bat-fun day on Saturday 19th. There’s lots of information at the Grant Museum homepage, which you can find here.

The full set of special events runs as follows. So if you’re in London, come along, get involved and say hello to us — members of the Bat Detective team will be attending or speaking at many of the events. We look forward to seeing you there. And to hear about our progress during British Science Week and keep updated with Bat Detective news, you can follow us on Twitter or Facebook.

Monday 14th March, 1:30pm–2:30pm
Bats at Lunchtime: The London Soundscape (talk)

A talk exploring how scientists at UCL are working to understand the health of London’s biodiversity through listening to its soundscape, including listening to bat calls.

Tuesday 15th March, 1:30pm–2:30pm
Bats at Lunchtime: On Dark Nights (talk)

A talk by researchers from the Bat Conservation Trust, discussing how street lights and other sources of urban light affect the nocturnal lives of bats.

Tuesday 15th March, 7pm—9pm
Bats: In The Dark 

Join In the Dark Radio for an evening of stories told through sound (like a cinema, but without the pictures) at the Grant Museum of Zoology during British Science Week. Enjoy the Museum after hours and listen to hand-picked audio inspired by Bat Detective, an audio visual citizen science project that asks people to identify bat calls. Discover the strange calls of these creatures of the night and find out more about these amazing flying mammals at this exploration of echolocation. This event is ticketed — book a place here.

Wednesday 16th March, 1:30pm–2:30pm
Bats at Lunchtime: Bat Detective (talk)

A talk from members of the Bat Detective team. Learn more about the ideas and science behind the Bat Detective citizen science project, and how the contributions of citizen scientists are helping us to develop tools to reliably identify bat calls.

Thursday 17th March, 1:30pm–2:30pm
Bats at Lunchtime: Bats In The Woods (talk)

A talk by researchers from the Bat Conservation Trust. Woodlands are excellent foraging and roosting areas for bats — learn about efforts to protect these important habitats.

Saturday 19th March, 1pm—5pm
The Brilliance of Bats family day

Bats are taking over the Grant Museum for a mini festival celebrating the brilliance of these flying mammals. Join the Museum for an afternoon of bat-related fun, try batty crafts with finger puppets and origami, take a closer look at some of specimens, hear from scientists investigating bats here in London and discover more about the work of the Bat Conservation Trust. This event is free so there is no need to book, just drop in from 1pm to 5pm.

Bat Detective USA: We’re in New York!

We’ve just landed in North America for the next stop of the Bat Detective World Tour! We’ve spent the last couple of months in the rather warmer climes of sub-Saharan Africa, asking for your help in listening for bat calls in data from Ghana and Zambia. Since the start of the World Tour you’ve listened to over 10511 unique audio clips and classified bats and insects in nearly 2000 of those, labels which will help to make our bat detection algorithms more accurate and robust. You can learn more about how your efforts are contributing to our research and bat population monitoring here, and keep an eye on the blog for future updates about how your work is further improving our automated bat detection software.

Following our time in Africa, we’ve now jetted across the Atlantic to arrive in New York, U.S.A. As of this morning we’ve uploaded a fresh set of audio data to Bat Detective, so visit the Bat Detective site right now to start searching and classifying. These data were recorded by iBats volunteers during surveys both within New York City itself as well as elsewhere in New York State. They cover a variety of urban and non-urban locations, including Central Park in Manhattan, Forest Park in Queens, Pelham Bay Park and Bronx Zoo, as well as Black Rock Forest, a 3,838-acre area of forest specially managed for maintenance of varied habitats and high species diversity. You can see the survey locations on the map below.


Locations of iBats New York survey data: Black Rock Forest, Forest Park Queens, Central Park, Bronx Zoo and Pelham Bay Park

With its temperate climate, New York lacks the very high species diversity of tropical regions, meaning that the sonic variation and insect noise in these recordings is often lower than in our recent African data. But there are plenty of fascinating bats to be heard. While listening through the data you might encounter any of several bat species found in this region and adapted to its seasonal climate. These include cave and mine-roosting species such as the abundant little brown bat and its larger relative the big brown bat, as well as the Eastern pipistrelle – a cousin of the well-known pipistrelle species you might have encountered in our European recordings – and the large, handsome Hoary bat (pictured below), whose range stretches throughout North and South America.

Bat conservation is currently an important topic in North America, mainly due to the ongoing spread of the deadly fungal disease white nose syndrome (WNS), which has caused large bat population declines in the northeastern US. Named after the furry white fungal mass often seen coating the muzzles and wings of affected individuals, WNS infects hibernating species such as little brown bats during the winter months, and is estimated to have killed over 6 million bats since it was first identified in New York in 2006. Research and conservation activities are ongoing to understand and attempt to contain the spread of WNS, and in response the United States, Canada and Mexico signed an agreement in 2015 to improve co-ordination of bat conservation responses across all three countries.

More broadly, infectious disease of wildlife is a serious and growing conservation threat to multiple species groups. The emergence of white nose syndrome in bats, for example, has parallels with the rapid spread of the amphibian fungal disease chytridiomycosis over the last two decades, which has driven massive declines and even extinctions in global amphibian populations. With most bat species difficult to monitor due to their nocturnal and elusive lifestyles, these challenges further emphasise the need for new tools and technologies to help researchers better understand the impacts of threats such as disease on bat populations – efforts we hope will be assisted by the automated softwares we’re currently developing with your assistance.

We hope you enjoy listening for bat calls in our New York data during this latest stage of the Bat Detective World Tour – click here to start searching. As ever, if you’re unsure about whether a call you’ve heard is a bat or not – or even just want to flag up something unusual or interesting you’ve discovered – click through to the Talk section, where you can discuss it with other citizen scientists and our own researchers.

Hoary bat (photo by J.N. Stuart, used under Creative Commons licensing)

Hoary bat (photo by J.N. Stuart, used under Creative Commons licensing)

Next on our World Tour: Kasanka National Park, Zambia

Happy new year from the Bat Detective team, and welcome to the next leg of our World Tour! Having spent the last month searching for bats in Ghana, we’ve travelled south to Zambia, another country in sub-Saharan Africa with high biodiversity and amazing wildlife. Today we’ve uploaded a new set of audio data to Bat Detective, containing recordings made in Kasanka National Park, which is shown on the map below. Head to the Bat Detective site now to start exploring the new data and classifying calls.

Location of Kasanka National Park, where the Zambia world tour data were recorded

Location of Kasanka National Park, where our Zambia world tour data were recorded

Kasanka is a relatively small national park located in the Lake Bangweulu basin, but has a broad range of habitats and an associated rich array of wildlife species, from famous large African fauna such as hippo and elephant, to a wide diversity of birds and bats. Indeed, like Accra where our Ghanaian World Tour audio data were recorded, one of Kasanka’s most famous wildlife sights is its massive gatherings of straw-coloured fruit bats (Eidolon helvum).

Each year, in November and December, around 1.5 million individuals arrive in Kasanka from the Congo Basin to feed from ripening fruit trees, in one of Africa’s most spectacular wildlife migrations (pictured below). Already known as one of the continent’s most widespread bat species, found from the base of the Sahara desert all the way to South Africa, research in recent years has confirmed that straw-coloured fruit bats are highly mobile and migratory. Recent research taking genetic samples from individuals across mainland Africa found that the straw-coloured fruit bat population is genetically mixed across the entire continent – an indicator of a highly connected population at a huge geographical scale. Indeed, tracking studies have also shown that individuals can travel huge distances, covering up to 370 kilometres in a night.

Fruit bats at Kasanka National Park (photo from

Fruit bats at Kasanka National Park (photo from

Similarly to our Ghana data, however, you won’t hear any fruit bats in these audio recordings from Zambia. The Pteropodidae, the genus to which fruit bats belong, do not use true ultrasonic echolocation to navigate, communicate and search for food.

However, Kasanka is home to a rich diversity of echolocating bat species, which you might encounter while listening through the data. Among these are two species of horseshoe bat, Lander’s and Hildebrandt’s horseshoe bat, with their distinctive constant-frequency calls; the tiny Schlieffen’s twilight bat (pictured below); and the banana pipistrelle, named for its habit of nesting in the leaves of banana and plantain trees. You might also have encountered some of the more widespread African species, such as the Angolan free-tailed bat, in our Ghana recordings.

Similarly to the Ghana data, the recordings from Zambia are very acoustically diverse – see our Ghana blog post for a guide to some of the sounds you might encounter. Occasionally mechanical noise or insect chirps can prove very challenging to tell apart from bat calls – if you’re unsure if a recording contains a bat call, just use the Talk section to flag it up and discuss with other users and the Bat Detective team. Good luck and happy searching!

Schlieffen's twilight bat

Schlieffen’s twilight bat (photo by Natalie Weber via

Next stop on the World Tour: We’re in Ghana!

Welcome to the second stop on the Bat Detective World Tour! We’ve spent the past few weeks uploading audio data from surveys in the UK, where the Bat Detective team and the Bat Conservation Trust are based. During that time our team of citizen scientists have completed over 7500 classifications, so thank you for your work during the first leg of the world tour. You can learn more about how your input is helping us to improve our automated bat detector softwares at this recent blog post.

Now, just as the UK weather is getting colder, we’ve jetted off to warmer climes. We’ve just arrived in Ghana in tropical West Africa, a country with rich biodiversity and a range of amazing bat species, and an important agricultural producer of crops such as cocoa, sugar cane, rubber, palm oil and bananas. Bats are pollinators for some of these crops, including some mango, cocoa and banana species – one of the many important ‘ecosystem services‘ that they provide for humans.

Starting today, 30th November, over the coming weeks we’re asking our bat detectives to listen through audio recordings of bat surveys around Ghana’s capital city of Accra (shown on the map below), conducted in 2010 by iBats volunteers. Click here to visit the Bat Detective site now to start listening and classifying. As you might expect for a tropical country with high wildlife species diversity and associated acoustic variety within the environment, many of the sounds you’ll encounter in these data are markedly different from the European audio data we’ve previously hosted on Bat Detective. They include different insect species, as well as a variety of bat species with their own fascinating, complex calls.

Accra, where the Ghana world tour audio data were collected

One particular bat species is one of Accra’s most famous urban residents – the straw-coloured fruit bat (Eidolon helvum). Massive gatherings of up to a million individuals of this large species are known for roosting in trees near the centre of the city, before spectacularly taking off at dusk and travelling outward en masse to forage. However, you won’t hear them in our Bat Detective recordings, as they’re part of the fruit bat family Pteropodidae, which do not use true ultrasonic echolocation to communicate and search for food. However, there are a wealth of echolocating bat species in this region of Africa that you might encounter while searching our Ghana data, from the widespread Angolan free-tailed bat and Noack’s roundleaf bat, to the distinctive yellow-winged bat (pictured below) a member of the false vampire bat family.

Although the Ghana recordings are often quite acoustically different to our previous European data, the same general rules for recognising different sounds still apply. Bat calls sound like a chirp, squeak or whistle, and usually show up on the spectrogram as defined pulses of sound, sometimes with additional harmonics at higher frequencies. The following two images are examples of bat calls from the Ghana data.



And the spectrogram below contains two distinct sets of bat calls from two individuals: one series of almost vertical calls at slightly lower frequency; and a separate, very bright horizontal call with two harmonics stacked at higher frequencies.


If you’re lucky you might also come across a ‘feeding buzz’ – a distinctive sequence of call pulses that gradually become closer and closer together as the bat approaches its prey, as shown in the clip below.


Insects often make rhythmic calls which can sound like a serrated rattling, buzzing or hooting. Visually they often look like repeated figures across the spectrogram at lower frequency than bat calls, such as in the following two clips. They can also often sound like car alarms or like distinct pulses within a messy spectrogram.



You might also encounter both insect calls and bat calls in the same clip, such as in the example below, where a bat call is shown in the blue outline, and the insect calls in green. You can usually tell the two apart by listening carefully for the bat’s distinctive chirping or whistling tone.


More detailed information and examples of different sound types are provided in the key at the bottom of the Bat Detective ‘classify’ page.

But if you’re still unsure about whether a sound is a bat or not – or even if you’ve just discovered a particularly strange or interesting clip that you want to draw attention to – just use the Talk function to discuss the call with others in the Bat Detective community and our researchers.

We hope you’ll enjoy searching for bat calls in our Ghana data over the coming few weeks. We’ll be staying in Africa for the next stop on the tour too, so keep an eye on this blog and our Twitter and Facebook pages for future news announcements.

Yellow-winged bat (photo by sandralee, displayed under Creative Commons licensing)

Yellow-winged bat (photo by sandralee, displayed under Creative Commons licensing)

Bat Detective World Tour begins! Welcome to the UK

The Bat Detective World Tour starts today! Over the next few months we’ll be regularly uploading new sets of data to Bat Detective from different countries across the globe – from Europe to Africa, the Americas and Asia – each with its own selection of bat species alongside other acoustic inhabitants. Today we begin our global bat search in the United Kingdom, home of the Bat Detective team and the Bat Conservation Trust (BCT). We’ve just uploaded a brand new set of audio recordings from the UK for our citizen scientists to explore, so to get involved, head across to the Bat Detective site right now.

These recordings are from surveys carried out across Great Britain between 2005 and 2010 – you can see their locations on the map below. The sounds you can expect to hear in these recordings are similar to the earlier Bat Detective data from Eastern Europe, including many of the same bat species, such as pipistrelles, serotines and noctule bats. Found across much of continental Europe, these are also among the UK’s most widespread bats, some of which you’ll probably have seen or heard through a detector if you’ve ever been out for a British bat walk or survey.

They’re also among the main species surveyed in the UK as part of the BCT’s National Bat Monitoring Programme (NBMP), a huge ongoing citizen science project that has been running for over 17 years. Carried out by thousands of volunteers who are trained to recognise different species calls using acoustic bat detectors, it’s a great example of how citizen science can make a real difference to our understanding of the status of wildlife populations.

iBats UK survey locations, which provided data for the UK segment of the Bat Detective World Tour

Survey locations from iBats UK project, which provided audio data for the UK segment of the Bat Detective World Tour.

You can read the most recent results report from the NBMP here. A paper by the NBMP team published in the scientific journal Biological Conservation in early 2015 showed that the long-term data collected by their volunteers could detect changes in bat populations equivalent to a Red Alert (a decline of 50% in 25 years). They also suggested that the current outlook for UK bat populations seems to be relatively positive, with most bat species showing either stable or slightly increasing population trends between 1997 and 2012 – promising initial news after the declines suffered by many species during the 20th century. These results should continue to assist in future monitoring of UK bat populations, and are evidence that citizen monitoring programmes can and do provide scientifically useful data for informing conservation. To find out more about the NBMP and how you can get involved, click here to head to their website.

Our goal with Bat Detective and iBats is to use similar citizen science-led approaches to develop new tools for monitoring bats on a global scale, while taking advantage of new advances in technology. As we’ve explained in previous blog posts, the data collected by iBats volunteers and labelled by Bat Detective users is helping us to develop automated software for reliably detecting and species-identifying surveyed bats. This will allow the analysis of massive amounts of survey data to be standardised across all volunteers and countries, thus increasing the usefulness of the data for drawing scientific conclusions. To read more about why collecting this data is important, read our earlier blog posts, here and here.

As well as some of our better-known bat species, while you’re exploring the UK Bat Detective data, you might also encounter a rather more uncommon visitor – the migratory Nathusius’ pipistrelle (Pipistrellus nathusii), which was named BatLife Europe’s bat of the year in 2014. Much is still unknown about the presence of this tiny traveller in the UK, since it’s rarely encountered here, although some individuals are known to be resident all year round. But researchers are finding increasing evidence to suggest that this species frequently crosses the North Sea between the UK and mainland Europe. In 2013 one individual that had originally been identity ringed near Bristol was found in the Netherlands, a direct distance of nearly 600 kilometres – a colossal trip for an animal that’s only about the size of a human thumb!

BCT are currently running a Nathusius’ pipistrelle project in the UK. Learning more about this amazing species will be important for reducing the potential human hazards it might encounter on its migrations, for example by placing wind turbines away from its main travel routes. So while searching the UK Bat Detective data you might be lucky and hear one too – for information on how to identify Nathusius’ pipistrelle from their calls, visit the BCT site.

Good luck and happy searching during this first leg of the Bat Detective World Tour! If you’re unsure about whether the sounds you’re hearing are bats or not – or just want to highlight something interesting you’ve found – visit the Talk section of the website to discuss your findings with the Bat Detective community.

Nathusius' pipstrelle

Nathusius’ pipistrelle (photo via Wikipedia).