A friend is in involved in the sat based version. They did manage incredible optimizations for power efficiency.

With a clock, pressure sensor, light sensor, a low power radio you can, and a bit of compute you can:

  * Use sunrise/sunset to get an idea of your longitude
  * Use the length of the day get an idea of your latitude 
  * Then use the above and some orbital calculations to find a 1-2 minute window when the sat will be visible.
  * Use the sat communications to upload a few 100 bytes and update your local clock, and get a better idea of your longitude.

> In looking at roost networks of bank swallows in Ontario you can identify that, “Oh, some bank swallows at night are actually going to different roosts from where their babies are,” and the adults will often trade off. We don’t know why, but they will sort of wander around and travel a hundred or more kilometers to a different place between nights.

That is actually pretty surprising to me. The weirdest insight from animal trackers I’d previously heard was kind of similar—that wolves regularly travel a lot further than scientists would have expected—but trading off roosts is a whole different level.

https://www.lotek.com/products/nanopin/

https://www.lotek.com/products/nanotags/

https://www.lotek.com/products/solar-nanotags-coded-vhf-for-...

These trackers on the legs remind of the 70 year old albatross https://news.ycombinator.com/item?id=38662454 which has the same tracker.

Does anyone have more in-depth technical details on these trackers? I assume they are UHF transmitters that require directional scanners?

Been bothered for a long time that wildlife conservationists are so quick to tag animals with labels and trackers left and right. Is it really helping, or is it rather control freakery and actionism when the natural habitat or food chain or whatever is simply shrinking and there's not much that can be done about it save for full-on stopping obvious causes? Can not at least animal identities and movement be tracked or estimated with minimal-invasive methods or cameras more intelligently?

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They are missing a huge chance by not using ultra cheap SDRs like RTLSDRs.

Edit: I see.. they are using RasPis. But it looks like a super complex setup.