By Ben Raines. Originally posted on AL.com.
Deep in the swamp, where the water runs dark and cypress knees spear from the mud, you'll hear the call, high and piercing.
"Sweet, sweet, sweet... sweet, sweet, sweet."
Quick! Eyes to the trees. A flash of pure gold, like a pet shop canary. Then its gone. But what a sight.
The prothonotary warbler is perhaps the most intense burst of color to be seen on the wing in the United States. It's gold body so remarkable that old time Cajuns in the swamps of Louisiana named the bird after the brilliant saffron hoods worn by the Prothonotary Apostolic, the pope's team of clerics in the old days.
It is a mouthful of a name for a bird once known simply as the golden swamp warbler. The former name is perhaps better suited, as it describes where you are most likely to see a prothonotary. They are seldom seen more than a few hundred feet from water, be it a creek, a lake or, most often, a swamp. They nest in hollows in dead trees, and it is hard to find a place with more dead trees than an Alabama swamp.
While there is not yet enough data to back it up, I suspect the Mobile-Tensaw Delta will be revealed to be one of the warblers primary breeding grounds. Other known areas include swamps in Louisiana, Virginia, and the Carolinas. But those places are not located 15 miles from the Gulf, at the center of the Dauphin Island Trans-migration throughway. I think a quick study will reveal the delta's importance to the survival of the species, whose population has declined somewhere between 40 and 50 percent since the 1960s.
Head to the thickly wooded portions of the delta and sit still. Within a few minutes you will hear the distinctive call of the warbler. Better yet, play its call on your smartphone, (search for "prothonotary warbler song" on Youtube) and warblers will magically appear out of the woods. It is not uncommon for me to call a half dozen birds right to my boat within 10 minutes in the heart of the delta. It is a delightful thing to find yourself surrounded by such cheerful and glowing birds. If you are lucky, one might choose to sit still nearby and call back to you in a sort of iphone/bird harmony.
"There are a lot of them out there now. You can see them at Dauphin Island as they come in for the migration. They are just a spectacular bird. People hear them more than they see them I think," said John Borom, president of the Mobile Bay chapter of the Audubon Society. "I think the Delta is a perfect, gigantic, and important nesting site for them. It is the exact type of habitat they prefer. You have big wooded swamps. Cypress and tupelo bum bottoms. People sometimes call them golden swamp warblers because of their association with the habitat. What a treat to see, such a spectacular brightly colored bird!"
Recent research by the Audubon Society chapter in Louisiana, Louisiana State University, Virginia Commonwealth University, and collaborators in other states has shed new light on the the migratory habits of the warblers.
Erik Johnson is one of the lead researchers. His group has tagged close to 100 warblers with tiny satellite geotrackers, each weighing about half a gram. The birds weigh about as much as two quarters, while the geotrackers weigh about the same as twenty grains of rice. The trackers create a record of where the birds were and when. They can record data for a year.
"The technology of geolocators has gotten small enough that we could do it, but you must catch the bird again to get the data," Johnson said, about the tagging work. Considering that the birds migrate from the United States to Central and South America, the prospect of catching the same bird again a year later might seem remote. "We found that the birds were coming back to the same patches of woods, even this little fragment of a swamp in an urban area."
When the group caught it's first returning bird, "it yielded all this data about its migratory path."
"That bird traveled 5,000 miles over the course of the year. It took him 3.5 months to get to his wintering grounds, and only 3.5 weeks to get back north," Johnson said. "Four birds from Virginia, a single bird from South Carolina, and about 11 birds from Louisiana all seem to be wintering in Colombia and Panama. That's a little bit of a surprise."
Johnson said the research may provide a breakthrough in reversing population declines in migratory birds, especially for species like warblers, that have been hit hard in recent decades.
"You may find that you have a breeding population decline, but you aren't losing breeding habitat," Johnson said, explaining that many of the swamps the warblers rely on in the spring/summer breeding season have been protected. "That's been a puzzle. This research highlights that you may be losing the wintering grounds. So you're conservation work may need to focus on that instead. It's telling us a lot about what kind of strategies we need to reverse population declines. There's a clear understanding, but a lack of data, that we need to be doing work on the non-breeding grounds. This helps show where those areas are when they migrate south."