Thursday, April 23, 2015

Lightening the Load for Longshot

The weather forecast for last Wednesday (April 15th) was for rain and thunderstorms. We had five volunteers signed up to come help with our Prothonotary Warbler banding project (better known as Project PROTHO), and when they all arrived at the visitor center at Francis Beidler Forest, it was pouring rain. We were nearly ready to cancel.

Things have a way of working out, though, and Mother Nature obliged for about six hours that day, giving us enough time to try to catch Longshot. If you haven't heard about the Prothonotary Warbler that retired Audubon South Carolina State Director Norm Brunswig affectionately named "Longshot," see our previous post here. Amazingly enough, this tiny bird (weighing about 14 grams) wore a small device called a geolocator (weighting about 0.4 grams) for the last 10 months, flying to somewhere in Central or South America during that time. It is our hope that the device itself will answer that precise question - where did he go? Geolocators take light level readings to infer a relative position, thus enabling researchers for the first time to track the long-term movements of a small bird.

Staff and volunteers transport banding equipment on the boardwalk. Photo courtesy of Mac Stone.
Before last week, we'd already tried once to catch Longshot without success. Imagine our worry: he travels 2,000-3,000 miles wearing this device, and then we can't catch him to take it off when he's 20 feet away from the boardwalk at Beidler Forest! Last week was our second chance at trying, and our fear was that he might become shy of our net and decoy, thus making him even more difficult to catch.

Sure enough, we arrived at his "spot" on the boardwalk around 9:00 a.m. and tried unsuccessfully to catch him once again. After about 30 minutes of trying, we admitted defeat and left to try to catch a few other Prothonotary Warblers that were unbanded.

We had much more success doing that! The pictures below are a few taken by our talented volunteers of the banding process.

Every bird that we band receives a silver, aluminum band from the United States Geological Survey. This band contains a number that corresponds to a national database, so that if this bird is ever captured again somewhere else, whoever catches it can learn exactly where and when it was originally banded. We also add color bands in a unique, three-color combination so that we can identify birds individually. Photo courtesy of Mac Stone.
These are the color bands that we'll be using in 2015. Each color corresponds with a number, and in addition to the silver USGS band that every bird gets, we can assign a unique alphanumeric combination to each bird. The red-yellow striped band has a slightly different number - this band will be used on every bird we catch this year (the 15 stands for 2015), but will not be used in subsequent years.
The bands don't hurt the birds and are extremely small/lightweight (see picture above for scale). This bird's new name will be A1500, based on the colors used and their arrangement on the bird.

In addition to leg bands, a standardized set of measurements is taken from every bird that we capture. This information will be compared with data from researchers in several other states that are capturing Prothonotaries and performing the same measurements. Photo courtesy of Marcie Daniels.

Once the birds are processed, we try to take a few documentary pictures and then release them as quickly as possible. Here, a volunteer releases a newly banded bird. Photo courtesy of Mac Stone.

We banded three new birds for the day, taking us through lunchtime. Near the end of our field day, we decided to take one more chance at catching the Prothonotary with the geolocator. We set the net up in PRECISELY the same spot that we banded him in July 2014,!!

"Longshot," the Prothonotary Warbler that's been carrying a geolocator since July 2014, is finally captured! Photo courtesy of Mac Stone.

Once he was removed from the net, we were able to get a close up look at the geolocator (pictured in center). This device was attached to the bird as a harness, looping around his upper legs using Stretch Magic. A simple snip with a pair of scissors and it was off! Photo courtesy of Mac Stone.

The recovered geolocator from "Longshot," lightening the load he has to carry by 0.4 grams! The right end of the device is the light sensing stock, the gray portion contains the battery and storage unit, and the brown string is the cut harness. Photo courtesy of Mac Stone.

A914, aka Longshot, before his release last Wednesday. A truly remarkable story! Photo courtesy of Marcie Daniels.

Once we captured and removed the geolocator, we released Longshot and packed up our gear. About 20 minutes after arriving back at the center, the rain set in again. We had a fortunate day of weather that allowed us to catch a very lucky bird!

Now that the geolocator is back in our possession, we're going to send it off to our Audubon colleagues in Louisiana who can hopefully use software to analysis the data. If it all works out, are fingers are crossed that his "backpack" will tell us not only where he spent his winter, but how he got there too.

Stay tuned to this blog for more updates on Longshot and our other banded birds!

Tuesday, April 14, 2015

Project PROTHO - 2015 update and the return of "Longshot"

In 2008, Audubon South Carolina began what is still known today as Project PROTHO, a citizen science endeavor to learn more about the population of Prothonotary Warblers living in the swamp at Francis Beidler Forest. This project has continued off and on since then - for a comprehensive history of Project PROTHO, see past posts written by former Education Director Mark Musselman here:

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, 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!

Like male Prothonotaries are apt to do, here's a picture of our geolocated bird carrying nesting materials to a cavity. Males usually arrive at Beidler before the females and will choose a handful of cavities to line with mosses and other materials...then they let the females choose which one they like best!

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!