Can multiple stations be used for trilateration?

Analysis and Data
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Hi All!

I’m a bat person and relatively new to Motus. I’m interested in using multiple stations to track bat use of the field site I work in. Has anyone done this before? I’d love some input before I purchase equipment.

Some context: I’m interested in bat use of prairie dog colonies. My lab has found that bats echolocate more over prairie dog colonies compared to adjacent non-colony areas.

The field site is we work at is The Nature Conservancy’s Smoky Valley Ranch in western Kansas, which is nearly 19,000 acres. It is also pretty flat, so line of sight shouldn’t be a big issue. This site has a Motus station (GPCD Smoky Valley (#10626)).

In 2022 and 2023 we set up a network of 20 CTT nodes on and off colony, calibrated the network, and tagged 10 bats with CTT PowerTags. We got some tantalizing results, suggesting that bats may be using the contact zone between habitat types. We’re following up on this with acoustic surveys this summer.

I would like to get a better idea of how bats are using the habitat at the ranch. I would prefer to avoid nodes to do this. Setting up the node network was very labor intensive even for 20 nodes, calibrating the network is time consuming, and a node network only gives a snapshot of where tagged animals are.

Which brings me to my original question. Can I set up additional Motus stations with directional antennas to locate/track bats? I have some internal funding to set up three additional stations, but I’d love some feedback on whether this could/should work.

Thanks!

Lorelei

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Hi Lorelei,

That sounds like a really interesting study! In theory, it’s possible to use multiple Motus stations to trilaterate/triangulate, but I think it can be quite challenging in practice (take what I have to say with a grain of salt since I’ve never tried to do this myself). I’m not sure it would end up being less labour-intensive than a node network, but your study area does sound like good conditions for this kind of thing - flat and open.

Here are a couple papers that may be relevant:

[Lenske and Nocera (2018) field test radio-telemetry.pdf|attachment]

Rueda-Uribe et al. (2024)

I recall Alyssa Sargent, one of the authors on the paper above, giving a talk at the American Ornithological Society meeting a couple years ago about comparing CTT nodes and trilateration from a smaller number of larger stations to study hummingbird movement. I couldn’t find a publication for that work, but it could be worth reaching out to the authors of that paper.

Cheers,

Amie

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Hi,

see our preprint from a few days ago, where we exactly do that in an easy to use R-package:

Rüppel, G., Karwinkel, T., Brust, V., & Schmaljohann, H. (2025). movetrack: An R package to model flight paths from radio-telemetry networks. https://doi.org/10.32942/X2JD13

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PS: A person, who has a very dense Motus network and also works with bats is Sander Lagerveld (ir. S (Sander) Lagerveld - WUR). he might also help out. Just look on the reciever map in the Netherlands and you instantly see how dense they are deploying stations.

Best, Thiemo

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Also check out some cool work in Hawaii by Jenny Smetzer et al:

Smetzer, J.R., Paxton, K.L. and Paxton, E.H., 2021. Individual and seasonal variation in the movement behavior of two tropical nectarivorous birds. Movement Ecology , 9 (1), p.36.

Smetzer, J.R., Paxton, K.L., Hart, P.J. and Paxton, E.H., 2022. Activity patterns of Hawaiian forest birds in a fragmented and continuous landscape. Journal of Avian Biology , 2022 (4), p.e02905. https://nsojournals.onlinelibrary.wiley.com/doi/pdf/10.1111/jav.02905

Paxton, K.L., Smetzer, J.R., Hart, P.J., Anderson, M.J. and Paxton, E.H., 2024. Landscape configuration alters movement behavior and space‐use of a Hawaiian forest bird community. Journal of Avian Biology , 2024 (1-2), p.e03117. https://nsojournals.onlinelibrary.wiley.com/doi/pdf/10.1111/jav.03117

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Hi Lorelie! I am a Postdoc in Christina Davy’s lab. We are doing something very similar with bats in our area. If you want to hear more about our equipment, setup, etc. please let me know (erinstukenholtz@cunet.carleton.ca). I am more than happy to share what we have learned and how we have improved our techniques. I will also be at NASBR this year to discuss some Motus research.

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Thank you so much for the papers!

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Thank you so much! I just emailed you.