LunAero observes migrating birds as they pass in front of the moon. (Image Credit: University of Oklahoma)
For centuries, scientists have been perplexed by birds and what they may be doing during the night. Some even theorized that birds would go underwater or in mud. In 1881, a scientist pointing a telescope at the moon caught a glimpse of birds migrating at night. University of Oklahoma researchers developed LunaAero, a system that observes birds as they pass in front of the moon.
LunaAero features a camera for recording purposes, spotting scope, motorized mount, and a small computer. It also runs on basic computer vision techniques to keep its sights set on the moon, even when it's moving. The system detects birts that observers may otherwise not notice. Also, ornithologists and bird enthusiasts can use the system since the mount supports varying telescopes.
This bird-tracking system can also generate log files that contain data on the recording time, frame counts, and camera sensor settings. The researchers are currently producing software for LunAero video analysis. As it stands now, humans need to manually retrieve video frames with birds and annotate their flight paths or patterns. Tests began in April and May 2018 and 2019.
LunAero recorded migrants crossing in front of the moon over ten frames. Each arrow represents the bird's orientation. (Image Credit: University of Oklahoma)
The team extracted a significant amount of data from the system. They say that you can determine a bird's species or genus if you make assumptions about which birds are taking flight in that area. For example, they can characterize each bird based on flight patterns, such as a nighthawk swooping up and down. Also, the system can provide precise flight directions while visualizing wind drift.
The ultimate goal is to use this technology as an alternative to bird migration techniques, including radar aeroecology. Radar aeroecology allows anyone to see bird migrants and how they fly out of a city or roost. However, the drawback is that it's impossible to determine what's being observed. For example, it may detect some water balloon shape in the sky, but the radar won't be able to determine if it's a bird, twelve birds, insects, or even a floating object.
Of course, anyone interested in nighttime bird watching can build their own LunAero with off-the-shelf materials and motors from Amazon. It's pretty affordable to assemble, costing only $150 without a telescope. It requires a Raspberry Pi computer, the most expensive component, to power the system. This setup is also beneficial because it allows a user to deploy multiple systems simultaneously. Combining the sensors generates data that you would normally see on high-quality instrumentation.
The researchers continued upgrading their system after they published the tech in a HardwareX 2020 journal and even allowed bird watchers to try it out. They say it can be used as a citizen science tool, and factors like weather conditions or a cloud covering the moon affect the system, so there are times when they need to reconfigure it. Now, the team is creating proof-of-concept and early data papers for the system. They also hope to see it integrated with today's migration technology in five years.
In October 2019, scientists used sophisticated GPS technology to track and plot the movement of 39 European nightjars over several weeks. The data revealed that birds would spend more time feeding at night when the moon was out. It revealed that the nightjars migrated for ten days during the full moon. This proves that animals use moonlight to help them migrate.
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