Geolocators
Geolocators have revolutionized ornithology. These tiny devices are providing new insights in to the migrations of bird species that were previously too small to track. Although manufactured versions are relatively cheap as tracking devices go ($100-$200 per tag), we’ve been making them at a cost of about $20 per tag. We hope to soon release our design and provide geolocator kits that you can assemble yourself.
Meanwhile here are some pics of our devices and some of the results they have produced:

This was one of our earlier designs. We call it the hatchback. It has a small solar cell on top that opportunitically charges the battery. To record light levels the tag simply measures the voltage from the solar cell. A downside to this design is the complex folding of the flexible circuitboard. It is time consuming and hard on the board’s small copper traces.

Hatchback tag on a Purple Martin

One of our first geolocator tracks. This is a Lark Sparrow from Ohio (see Ross et al, Animal Migration 2:29-33. doi: 10.2478/ami-2014-000)

Here’s our newer geolocation. It uses a fancy real time clock that has an ‘off switch’ that can shut down all of the other components when logging is not happening. This helps conserver battery power. Some results from this tag are coming soon.