Night and low light photography has gotten easier and easier. With film, this type of photography was a challenge. Everything from color to color balance to "noise" (grain) to exposure problems due to reciprocity failure made night photography often unpredictable. Now with white balance control, excellent results at high ISOs and the ability to check exposure as you go, this is no longer such a problem. Digital photography makes night images accessible for any photographer.
That said, I can tell you that there are still a LOT of challenges for bat photography. I have set myself a goal of capturing images of bats on location, not captured and released for controlled photography. There is a reason photographers have not done that too often. It is hard!
Yet, for me, this represents another aspect of nature that is underrepresented in nature photography. Bats are a very important part of most ecosystems, yet when you see books about those ecosystems, you'll often find little to nothing about bats. Roughly 1/2 of each day, night, is consistently "under-reported" for nature. That is like trying to understand Mt. Rainier without considering its glaciers or Alaska without including its bears.
I get it, though, with photography of night life in nature. It is hard. Remote camera traps, including "trail cams" sold to hunters (and used by many naturalists), can record night life, but only when that life crosses in front of the camera. Bats are small, and with flight, they can go anywhere at anytime. Their flight makes bats neither contained or as predictable as terrestrial night animals (which makes the latter good subjects for trail cams).
One thing that is somewhat predictable for bats is their emergence from large colonies at dusk. Not all bats live in such aggregations, but when they do, their emergence can offer a wonderful experience of night life.
We had to privilege to experience some amazing Mexican free-tailed bat emergences in Austin over the Memorial Day weekend. The bat colony under the Congress Ave. bridge just south of downtown Austin is well known. Hundreds of people show up to watch every night, and on busy nights, that can be thousands. You will see every age, sex, culture and race there to see the bats. They have become a popular destination for folks coming to Austin. Over two million bats live in that bridge, the largest urban bat colony in the world.
We were there on a busy Saturday night – the park and lake below the bridge were filled with people. At this time of year when female bats typically have young, the Mexican free-tails often emerge earlier than sunset so they can get out and start feeding. There had been a lot of heavy rain in the area in the days before, so the bats would not have gone out much to feed, if at all.
But they did not start coming out until nearly 9 pm, about 30 minutes after sunset. It was definitely night and dark.
The bats became very hard to see. I had to use a flash to get anything, and only when the image showed on my LCD did I really see the bats. There could be no composing of bats or waiting until a certain number were in the frame because I could not see them before taking the picture. The photo opps were not good. A dad and his son near us were having trouble seeing the bats, so I showed them my LCD and that made their experience more real (and my work worthwhile, even if not that great). The local folks said that a hawk had been hanging around the bridge of late and that probably caused the bats to delay emerging until it was dark.
A friend who lives in the area, Ted Keller, had suggested we check out the I-35 bridge over McNeil Rd. in Round Rock (just north of Austin). He said that bridge also had millions of bats using it as a bat "house." We went there on Sunday night. The evening was sunny with hardly a cloud. The bats started coming out a little before official sunset and this was an amazing nature experience. My wife loves nature, but does not have the love of bats I do, but she was in awe and loved it. The bats swirled under the bridge, then came out in large groups out of the southeast end of the bridge.
The groups went into the sky and you could watch them go. The mass of bats and their group flight in the air reminded me of the starling flights going to roost in England (I have only seen videos of them). There were not many people there to watch, but they all just stood and watched with great attention as these bats came out in waves over the next half hour (they actually kept going longer, but when it was dark and getting hard to see them, the people left).
Easy to photograph? Yes and no. Easy to show bats with the urban location. Hard to give a feeling of the clouds of bats and show the bats, too (like most U.S. bats, Mexican free-tails are very small). I tried doing a variety of things, near and far, changing my position, etc. I was glad I was coming back the next day because I would know better what to do. Still, the experience was amazing.
Next day, Monday, sunset came. No bats. The bats did not start coming out until nearly 9 pm, like the Congress Ave. bats. I had seen a hawk fly through the flying bats on Sunday night, and it seemed like it caught a bat, though it was hard to tell at the distance.
I get it. These little bats are very vulnerable when it is light, so they delay emergence to make it harder for hawks to get them, even though that means going out for food later (bats have a very high metabolism, especially with young to feed, so that does matter).
This made the photography very, very challenging. I had to keep increasing my ISO in order to get a shutter speed fast enough to stop the action of the wings enough to recognize the bats as bats.
But it quickly got too dark for that, so I started using my flash (which I had put fresh batteries into so that it would recycle quickly).
Now came a whole new challenge. How to focus! It was not bright enough to focus easily focus where the bats were. Lights from the street gave enough light on the bridge to focus there, but I was shooting with a long telephoto with limited depth of field, so the bats would be out of focus. They were moving too fast to focus on, even with a light. So I used the bridge focus as a starting point and gradually changed my focus manually until I started getting some in focus.
Since bats fly, they don't follow a narrow path, so sometimes I would get them in focus, sometimes not. I kept tweaking my focus, which sometimes helped, sometimes hurt. I am thinking about trying a laser measurer for bats so that I can measure a distance and use that for focus.
Still, it was fun and I learned a lot.