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Mozambique Diary: Shooting bats

Leaf-nosed bats (Hipposideros sp.) in a cave of Cheringoma Plateau, Gorongosa National Park.

Leaf-nosed bats (Hipposideros sp.) in a cave of Cheringoma Plateau, Gorongosa National Park.

My entire last month was a blur of hectic activity, related mostly to the opening of the E.O. Wilson Biodiversity Laboratory in Gorongosa National Park. This kept me from updating the blog, but it was definitely worth it – the Lab is a fantastic facility that will serve as a research base to current and future scientists in the park, and as a center of advanced biodiversity education for Mozambican students for years to come (I just finished teaching its first African entomology workshop there, and it was great.) We are also creating the Gorongosa Synoptic Collection, which has the ambitious goal of documenting, over the next 15-20 years, all (or at least as much as physically possible) multicellular diversity of the park – I will try to post frequent updates from this effort. In the meantime, I would like to invite all biologists to come and work in Gorongosa – there is an entire universe of unexplored life out there, waiting to be studied and saved. Contact me if you are interested – Gorongosa wants your research projects, and we will help you make them happen.

Slit-faced bat (Nycteris cf. thebaica) from Gorongosa and a sonogram of its echolocation.

Slit-faced bat (Nycteris cf. thebaica) from Gorongosa and a sonogram of its echolocation.

One of the many benefits of having a permanent and safe logistical base in a place as biologically rich as Gorongosa is that I am not afraid to bring and leave behind my expensive high tech gear, and experiment with it. For months I had been dying to try out my high speed photography system, and finally was able to use it last month to shoot flying bats in the comfort of our lab. Now, bats have been photographed in flight by many, and the technology to do so has existed since at least the 1980’s. But, as far as I could tell, few had tried to take images of flying bats using the white background technique, made popular by the Meet Your Neighbours project, and I really wanted to try it.

An orange form of a Horseshoe bat (Rhinolophus landeri) from Gorongosa and a sonogram of its echolocation.

An orange form of the Horseshoe bat (Rhinolophus landeri) from Gorongosa and a sonogram of its echolocation.

The setup for photographing bats in flight will be familiar to anybody who has ever worked with high speed photography: I used an external, very fast shutter (6mS response time, 10-50 times faster than the shutter in a typical SLR) mounted on a Canon 7D with a 100mm macro lens, triggered by two intersecting laser beams, and with four Canon flash heads that provided the illumination. Cognisys is a company that sells turnkey solutions for high speed photography, and their excellent StopShot system is what created the basis of my setup. The tricky part was to create a stage where the bats’ flight path was relatively narrow, allowing me to illuminate it properly. Last year I photographed bats in a cave, which was relatively easy, but gave me little control over the lighting. I needed to restrict their movement better, and decided to bring a large diffusion box that I would then turn into a flight chamber for the bats.

The box was about 1 m (3 ft) long, giving even the largest Gorongosa species ample room to fly. On the sides of the box I cut out two small windows (covered with thin, clear Perspex) that allowed the laser beams to go through. The front of the box had to remain unobstructed to the lens, but something had to stop the bats from flying out; I ended up using a large piece of thin glass (and had to adjust the flashes so that they would not reflect off the glass). But somebody had to put the bats in there, and it was not going to be me (one word – rabies!)

Leaf-nosed bat (Hipposideros caffer) from Gorongosa and a sonogram of its echolocation.

Leaf-nosed bat (Hipposideros caffer) from Gorongosa and a sonogram of its echolocation.

Luckily, I got help from Jen Guyton, a Princeton graduate student and a bat specialist, who is working on her Ph.D. in Gorongosa. Since capturing bats to get samples of their DNA (or rather the DNA of their prey) was part of her nightly routine, Jen was able to bring live bats to my studio and control them while I took the photos. Once all the technical kinks were ironed out, the system worked like a charm – in a few minutes I would get multiple shots of each bat, and then the animal was removed from the chamber unharmed.

A studio setup for photographing bats in flight: (1) Cognisys high speed shutter, mounted on Canon 100mm lens; (2) a laser and a laser beam sensor (an identical but vertically reversed set is positioned on the opposite side of the box).

A studio setup for photographing bats in flight: (1) Cognisys high speed shutter, mounted on a Canon 100mm lens; (2) a laser and a laser beam sensor (an identical but vertically reversed set is positioned on the opposite side of the box).

But some species turned out to be more difficult than others – members of the family Molossidae (my favorite bats) are not able to lift off from horizontal surfaces and thus could not fly in the box. Next month I plan to photograph them in the wild by combining this system with a UV light – I hope that the bats will be attracted to insects coming to the light (which they often are) and sooner or later will hit the laser trigger. Watch this space to see if it worked.

One final note – don’t try any of this at home! Nobody but professionals, vaccinated against rabies, legally permitted, and fully trained to handle live bats should ever attempt catching these animals. If you are interested in photographing bats, get in touch with a mammalogist at a nearby university or a conservation group that works with these mammals, and they may be able to help you. They are an awesome group of animals, but don’t risk their or your own life. Having seen Gorongosa bats’ unbelievably sharp, lyssavirus-carrying teeth in action, I now think of them as flying vipers – cool, beautiful and fast and, potentially, very deadly.

A grey form of the Horseshoe bat (Rhinolophus landeri) from Gorongosa

A grey form of the Horseshoe bat (Rhinolophus landeri) from Gorongosa

 

When life gives you lemons

An 8 second exposure of mating horseshoe crabs (ISO 1250, 14mm, f 7.1) – I like these kinds of shots, but they give the false impression of the scene being static and dreamy.

An 8 second exposure of mating horseshoe crabs (ISO 1250, 14mm, f 7.1) – I like these kinds of shots, but they give the false impression of the scene being static and dreamy.

Last weekend I drove with a couple of friends to Delaware to watch what surely must be one of the most amazing natural spectacles in North America, the annual mass spawning of Atlantic horseshoe crabs. I do it almost every year, and over time the eight hour drive from Boston to Delaware Bay has become a ritual, my way of communing with the ancient arthropods. (It is also an opportunity for me to gorge on delicious things I normally try to avoid – gas station donuts, Big Macs – after all, there is simply no way to eat healthily while on the road, right?)

A trip to Delaware allows me to flex my photographic muscles and try new approaches to capturing a scene that has been photographed a zillion times already, but this year the circumstances were not particularly favorable for photography. In fact, they could not have been worse. High tides, which is the time when horseshoe crabs emerge from the ocean to lay eggs, were late at night, long after the sun had set. It was new moon and the sky was overcast, hiding the stars. This challenge presented me with three possible options. I could forget about pictures and simply enjoy the show with a beer in my hand – I have already taken thousands of photos of horseshoe crabs, and didn’t really need to take any more. Very tempting. I could also shoot with flashes and get crisp, clinical shots of the crabs’ aggregations. Boring. Or I could think of a new, unorthodox way to shoot them.

Once I used some fill-in light I was able to capture the true, dynamic character of the scene – waves crashing over the bodies of horseshoe crabs tumbling in the brown waters of the Delaware Bay.

Once I used some fill-in light I was able to capture the true, dynamic character of the scene – waves crashing over the bodies of horseshoe crabs tumbling in the brown waters of the Delaware Bay.

Photographing horseshoe crabs is not easy even under the best of circumstances – the light is usually low, salt water splashes on the equipment, waves move the tripod. In the near darkness of the new moon things were even tougher. Still, I was determined to get at least one interesting shot. The idea was to capture the dynamic nature of the spectacle and convey the darkness of its surroundings. I decided to go for a low angle shot of the animals tumbling in the waves, while showing the darkening skyline. I used my Canon 7D with a Canon 14mm fisheye, mounted on a tripod (dug deep into the sand to stabilize it) and positioned less than a foot above the crabs in the splash zone. I had to wipe the camera and lens every minute, but soon they were both dripping wet. I tried a bunch of simple, long exposures (30 seconds or longer), but those produced static, if somewhat dreamy pictures, where the waves turned into a silky mist enveloping the animals. I needed extra light to capture individual waves.

Horseshoe crabs, like some of their distant arachnid cousins, fluoresce under ultraviolet light. A dark, moonless night last weekend was a good opportunity to photograph it.

Horseshoe crabs, like some of their distant arachnid cousins, fluoresce under ultraviolet light. A dark, moonless night last weekend was a good opportunity to photograph it.

A pop of flash often works very well in such situations, freezing some of the action, while the rest of the exposure time allows for the scene to become more diffused and messy. But I did not like the harshness of the flash, and even my headlamp produced illumination that was too bright for a long, ISO 1600 exposure. Only after I wrapped it in a few layers of paper towels did the light become diffused and soft enough for me to start “painting” the scene with it. In the end I was able to capture an image very close to what I had in mind – a melee of animals among waves splashing against their bodies, while the last traces of sunlight reflect off the clouds above. The shot is grainy and dark, but to me it feels right and true to the circumstances. I guess the lesson here is that when life gives you lemons, you photograph them.

During the day, when horseshoe crabs were deep in the ocean, I photographed other things. Great Blue Heron hunting mud crabs in the marshes of the Prime Hook Nature Reserve made for an interesting subject.

During the day, when horseshoe crabs were deep in the ocean, I photographed other things. A Great Blue Heron hunting mud crabs in the marshes of the Prime Hook Nature Reserve made for an interesting subject.

Natural areas surrounding the Delaware Bay are full of amazing creatures. I found this Eastern Mud Turtle (Kinosternon subrubrum) on a country road near the ocean.

Natural areas surrounding the Delaware Bay are full of amazing creatures. I found this Eastern Mud Turtle (Kinosternon subrubrum) on a country road near the ocean.

BugShot 2013 in Belize

There are still a few slots available for BugShot 2013, a great opportunity to learn macrophotography in the rainforest of Belize from Alex Wild, Thomas Shahan, John Abbott, and yours truly. It is going to be a great event, at a fantastic location. You will not only discover the carefully guarded secrets of some of the best insect photographers in the world (e.g., what cameras they really use, how they drug their insects so that they sit absolutely still* etc.), but you will also learn a lot about insect biology and behavior, and visit a variety of Neotropical habitats.

Head on the BugShot.net to grab one of the few remaining spaces.

*) I am kidding, of course – real nature photographers never drug, chill, or kill their subjects.