After a gap in 2012 and 2013, this project picked back up in 2014 with our interest in geolocator technology. A geolocator is a light-sensing device that is (currently) the most advanced technology available to track the movements of a small bird like the Prothonotary Warbler. These devices take light level readings each day that are ultimately used to determine the bird's estimated latitude/longitude position. The geolocators are worn as a "backpack," with a harness securing the geolocator to the bird and a small light stock sticking out of the end. The biggest catch with using geolocators is that they don't work in real time - birds must be caught, fitted with a geolocator, then captured again the following year to have the device removed!
So why use these devices at all? There's a big question that Audubon SC hasn't been able to answer: where do our birds go when they leave the swamp? We like to think that we keep the swamp a healthy place for these warblers, but we only host them for less than half of the year. In the winter, Prothonotaries spend their time in Central and South America (see our previous post here about a recent trip to Panama to see these birds). But what area specifically? Is it a healthy ecosystem? Is it threatened by development as so many coastal mangroves are? Is there something that we could be doing in another country that would help these birds?
There are many questions still to answer, so in 2014 we began banding birds again to establish a population of known individuals that we could potentially use as candidates to wear geolocators. The permitting and timing in 2014 left us in a bit of a bind so while we were planning to deploy four geolocators as part of a pilot project, we were only able to deploy one.
|A Prothonotary Warbler about to be fitted with the only geolocator we deployed. We captured, attached the geolocator, and released this bird in July 2014.|
The odds of ever seeing a banded bird again once it leaves to migrate are very low, less than a 1% chance. Prothonotary Warblers, however, make good candidates for geolocators because they show high site fidelity (fancy term meaning that they like to return to the same wetlands from year to year).
Imagine our surprise when a group of bird-watchers saw this very special bird on April 4th, 2015....in EXACTLY the same spot on the boardwalk where we captured it last July! This bird likely traveled a round-trip flight of approximately 3,000 miles - only to come back again to the same section of Beidler Forest. And for the first time ever, he's carrying technology that will hopefully tell us precisely where he went...and how he got there!
|Our returning "geolocated" bird (aka Longshot) seen on April 4th at Francis Beidler Forest. Note the small white blob on his back - that's the light stock of the geolocator!|
|Another angle of "Longshot" and his geolocator. Note that he, like many of the birds we're studying, is color banded. Each bird gets a unique 3-band combination so that we can identify each one individually.|
So, remember the "catch" that we mentioned? That's right, we still have to catch this little guy again to get the geolocator off before we can learn anything. We'll be trying to do that this week, so stay tuned to this blog for updates!