The article seemed pretty devoid of technical details and left me curious as well. That said, this sentence might give us some insight: "The loggers took years

The article seemed pretty devoid of technical details and left me curious as well. That said, this sentence might give us some insight: "The loggers took years to perfect and I can still remember the excitement of getting the first one back that had successfully detected a boat’s radar." "Getting the first one back" makes me think that they physically had to retrieve the sensor, rather than have data transmitted. I am aware of two kinds of trackers deployed on birds. The first can note their location via GPS at regular intervals and send that data to cell towers when in range. I've only heard about these being deployed on larger birds such as Peregrine Falcons [0] or Snowy Owls [1]. The second type uses daylight to gather location data. If you know when the sun rose and set, relative to UTC, you can pinpoint your location to within ~100 miles. Trackers using this technology can be much smaller, but the bird has to be recaptured for data to be retrieved. Trackers like this were used within the last decade to finally uncover the location where Black Swifts who breed in the United States spent their winter. These small birds flew all the way to Brazil and returned the next summer to the exact same nesting location they used in prior years. Similar trackers, which also had accelerometers, were used to prove the Common Swifts sometimes fly non-stop all winter, sleeping while they fly. Given the text I quoted and the fact that albatrosses rarely come near any sort of radio receiver, I suspect the trackers must be retrieved from birds, likely on the breeding grounds, which would make the lag monumental. Perhaps it's possible that they're able to do some sort of satellite transmission, but that would seem very challenging indeed. [0] https://madisonaudubon.org/fff/2016/10/25/featured-sanctuary-bird-peregrine-falcon https://madisonaudubon.org/fff/2016/10/25/featured-sanctuary... (The main site appears to be down) [1] https://www.projectsnowstorm.org/ https://www.projectsnowstorm.org/