Collecting Bat Acoustic Data Using Passive Recorders in Costa Rica

Published on: Author: ahall6 Leave a comment

Greetings friends,

This is my first foreign correspondence while I am doing research on bats in Costa Rica. I will be following up at the end of my trip to sum up what I have learned from this experience. Currently, I am conducting acoustic surveys across Costa Rica using two Wildlife Acoustics SM4BAT full-spectrum passive recorders to investigate the impacts of land use on bat activity and species assemblage. “Passive” means these recorders can be left unattended with a set schedule to record for months at a time (batteries willing). “Full-spectrum” means my recorders pick up a lot of information about the echolocation calls bats are producing while navigating and foraging, such as change in intensity and frequency over time. I run the recordings through a computer program which listens for characteristic calls of different species. At the end of this project, I plan to classify the recordings in three acoustic guilds (low, medium, and high frequency calls) and look for correlations with land-use and environmental data. I hope this will elucidate the impacts environmental management decisions have on bat communities across Costa Rica.


My project is part of a larger National Science Foundation funded project led by Dr. Beck (St. Edward’s University) and Dr. Wasserman (Indiana University) looking at the impacts of land-use on primates. My four fellow interns are researching antibiotic resistance and hormone levels in primates (they follow monkeys around and collect fecal samples), water quality of streams entering/inside/leaving forest fragments, fig trees, air quality, and the social implications of eco-tourism. Meanwhile, I am the bat lady. We arrived January 2nd, and after about a week of setting up, we started data collection.


What have I learned in my first five weeks here?

  1. The weather and the environment are the rulers of the quality of data. Even though it is the ‘dry season’, it rained almost every day for the first four weeks we spent in La Selva Biological Research Station. I have not spent much time analyzing my data yet (as we spend most of our days in the field), but I average around 1,000 recordings a night per recorder from sunset to sunrise. Many of these files are ‘noise files’ filled with static, as the rainforest is a very noisy place with a lot of wind, rain, loud insects and animals. I am looking forward to seeing if there is a difference in the quality of recordings here at Las Cruces Biological Research Station where the weather is dry and not very windy.
  2. Sleep and food are paramount. I consider your body as part of your equipment, and if you do not take care of yourself, it will be harder to take care of your project. Field work is no joke and even though I work hard to get 8 hours of sleep a night, I always want more. Hiking miles a day through the forest carrying up to 20 pounds of equipment in the pouring rain while worrying about snakes and bullet ants is an experience which is hard to describe. But I enjoy every minute of it and will miss it when it is over.
  3. It is very important to get along with your teammates. We are going to be together for 10 weeks, every single day. I love my team and we are making amazing memories here in the jungle. If we did not get along, this would be a very different experience.
  4. I am lucky to have such supportive friends, family, and colleagues. The constant encouragement from everyone makes being away from home very easy. That being said, this is a marathon, not a sprint! I have 5 weeks left and I know at some point all of us will need some TLC and a shoulder to cry on when we are just missing that comfort of home. But, I love traveling and am fortunate to have this opportunity to conduct funded research in a beautiful country on awesome animals. We’ve done some really cool things: walked across Costa Rica’s second-longest bridge in Tirimbina, climbed a 46-meter-high tower overlooking the forest canopy where we got to watch Howler monkeys and White-faced Capuchins flit through the trees just 50 feet away, gone on night hikes and seen Eyelash Vipers and Red-eyed tree frogs, and watched rivers double in depth overnight. If anyone ever asked me if they should leave the comfort of home for an internship in a different country, I would say “GO FOR IT!” It takes a special kind of person to take that leap and it is unbelievably rewarding.
  5. It’s all worth it for the bats! At La Selva, we saw Proboscis bats and Greater White-lined bats every day when we walked out of our cabin. I’m sure I will see more species as time goes on. But getting to see their little faces and watching them leave every night to feed was such a neat experience. Everyone I talk to is eager to learn all the fun facts I can throw at them. Many people are surprised to find out not all bats are vampiric (3 of the approximate 1200 species drink blood). They love hearing about the special role bats play in ecosystems as seed-dispersers, pollinators, and insect-suppressors. Anything I can do to improve the understanding, empathy, and appreciation for these bats, I will!


Hopefully I, you, and everyone who knows and loves bats can help change the associated stigma over time to where they can be loved and appreciated for their insane evolutionary history, ecosystem services they provide, and their wonderful personalities.

Read my next blog post to learn about the results of my data!

Feel free to email me for any questions or comments (

Tata for now!





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