My Project

I realize that I have not explained my research on my blog yet, so I’ll give a little background information and the overall goals of my project.

I will be studying the Southern Bentwing Bat (Miniopterus schreibersii bassanii) at Naracoorte Caves National Park, South Australia. The overall aim of my project is to monitor the bats at the maternity cave in Naracoorte and at their overwintering sites throughout South East South Australia.

The Southern Bentwing Bat was formally listed as Critically Endangered under the Environment Protection and Biodiversity Conservation Act of 1999 based on the fact that the sub-species has undergone a reduction in population by about 67% over three generations (from about 100,000-200,000 individuals in the 1960s to about 30,000 individuals in 2009) and that it has a highly restricted range, relying on only two maternity caves (Bat Cave in Naracoorte and Starlight Cave in Warrnambool, Victoria). We know that about 10,000 individuals die each year. My project will provide detailed information about the population dynamics of this species and will be a step towards determining where, when, and why so many individuals don’t survive each year.  

Throughout the year I will do several things to monitor the bat population. First, I will take regular fly-out counts with thermal imaging cameras to monitor population trends at Bat Cave and determine the peak population size. By doing these counts regularly we will be able to see seasonal population trends throughout the year and get an idea of how weather affects nightly emergences. This is what I have been doing since I got here in September. I try to go out every night, although that doesn’t always happen due to bad weather (it’s not good to take the expensive cameras out into the rain!) or me travelling. When I take a count, I start setting up the cameras about 45 minutes before dusk (so 6:30pm now that Daylight Savings Time has begun). The bats usually start coming out around 7:15pm and the emergence typically lasts about an hour to an hour and a half. I record the whole time onto a cassette tape. After that’s done, I go into the Bat Center (a short walk from the cave) to use the infrared cameras inside the cave to see if there are any bats left inside. Usually not all the bats come out, so most of my counts are probably underestimates. Then I go home (usually by 9:30pm) and upload the census to the computer. Then I run the analysis, which consists of playing around with the software parameters to get the best visualization of the bats and double checking the count that the computer does. Most of the time I have to run several “scenarios” until the computer count matches closely with my manual count (I do several one minute counts to check against the computer count). This can take awhile but it’s pretty fun, like a puzzle! In addition, a new laser beam system will soon be installed (by students at the University of South Australia) so I will be able to compare nightly emergence numbers obtained from this system with numbers obtained from the thermal imaging cameras. Once the laser beam system is up and running, it will give us detailed information on activity patterns throughout the night, which will be really neat to see.

Taking a census at Bat Cave with the thermal imaging camera

Second, I will monitor pup health in the cave to watch for signs of disease or starvation. I will do this by visually observing pups with the infrared cameras in the Bat Center to look for signs of starvation or lesions and by taking photographs inside the cave to estimate the number of pups present. These observations can then be used to assist with determining possible causes of any observed starvation or disease. This will start once the pups are born in early December.

A view of the bats inside the cave with the infrared cameras

Third, I will conduct overwinter cave surveys throughout the South East region of South Australia. Most of the Southern Bentwing Bats congregate in the two maternity caves during the summer and then disperse to over 60 overwintering sites to spend the winter in torpor. Taking overwintering surveys will provide us with information about dispersal patterns from the maternity colonies as well as information about sites/caves of priority for restoration or conservation. Conducting these surveys will involve organizing a group of volunteers to go into the many caves in the region on the same day during the winter (sometime in June). In order to get an accurate count, it’s important that all of the caves (or as many as are accessible) are investigated on the same day because bats may move between caves.

Fourth, I will monitor the health of individual bats around Bat Cave by trapping with harp traps (I have never used these before so I’m pretty excited!) and possibly mist nets once a month. When we catch the bats during these trapping sessions, we will record basic data on each bat, such as weight, age, forearm length, overall condition, etc. We will also record some echolocation calls from the bats to build a call library. This library will be useful in the future when doing bat surveys with acoustic monitoring (so calls recorded during the survey can be compared to the known calls of the Southern Bentwing Bat).

In addition to the research aspects of my project, I will aid in the development of a public interpretation program at Naracoorte Caves National Park that minimizes the impact on the bats while engaging the public in conservation efforts. I am interested in public engagement and helping the general public understand the importance of bats, so I am very excited about this part of the project.

As you can see, there’s a lot going on with this project and my work over the next year will only begin to address some of the knowledge gaps for the Southern Bentwing Bat. Hopefully the information I gather will aid in the management and recovery of this Critically Endangered species!