[NSF] [Conserving any species is challenging, but how do you conserve what you can’t follow?]
[Nate] They can turn on a dime, and they’re going so fast, and then just over your head you suddenly hear this, this whoosh. And they’re all zig-zagging, it sounds like a bunch of, you know, air force jets heading over your head. And then when you think about them being able to fly all the way to South America, possibly in one jump, they can go wherever they want.
[Narrator] It’s hard to believe that you could lose track of 70000 of anything, but each year, the long-distance migrant the Hudsonian Godwit pulls a vanishing act that has the scientific world scratching its head.
[Nate] One day they’re on their breeding grounds on one side the globe and then proof, they’re gone, they disappear, and then a couple months later they show up a hemisphere away.
[Narrator] Off the coast of southern Chile, an international team of scientists is working to capture and tag Hudsonian Godwits. It’s an effort to reveal secrets to one of the world’s most dramatic and mysterious bird migrations. Nathan Senner is a competitive marathon runner and Hudsonian Godwit expert from Cornell University. He’s been studying shorebirds in his native Alaska since he was 16 years old.
If the team is going to succeed, they’ll have to trap, band, and release at least a hundred Godwits over the next five days, creating a marked population birds they’ll be able to track throughout their annual migration. But before they can start catching birds, the team will first have to find them.
Deep in the Southern Hemisphere, tucked between the cold Pacific waters and the rugged Chilean coast, is Chiloé Island. With rolling green hills, tranquil bays, and marine-rich coastline, it’s the hub of Chile’s booming aquaculture industry. But it’s also one of the most important sites in the annual cycle of the Hudsonian Godwit. And it’s the critical location for the team in their attempt to reach the birds.
[Nate] Chiloé is really the place to be to watch Hudsonian Godwits. There are more birds here in closer proximity to places that we can access than really anywhere else in the world.
[Narrator] Each November, the inhabitants of Chiloé share their island home with tens of thousands of wintering Godwits that have just returned from their breeding grounds in the Alaskan and Canadian Arctic, a grueling 9000 miles away.
[Nate] These birds are really in for rest and relaxation. It’s really a resort town for Godwits.
[Narrator] But its not the pastoral landscapes or quaint fishing villages that bring the Godwits back to Chiloé each year. It’s the mud. Every six hours twenty-foot tides reveal massive moonscapes of mud. And while this might leave Chiloé’s human inhabitants feeling a little stranded, for the shorebirds it’s a non-stop all-you-can-eat affair.
[Nate] The mud flats are really the place to be for Hudsonian Godwits. They have what is really a wide variety of food that may not be apparent to the human eye.
[Narrator] Chiloé’s tidal mudflats are rich with high-protein invertebrates like mussels and worms, and the Godwits’ 5-inch-long narrow bill is the perfect tool for probing deep into the mud and extracting them.
[Nate] At low tide Hudsonian Godwits are feeding like crazy, that’s really their time to gorge themselves and they’re right at the tide line in the softest mud.
[Narrator] The food that Godwits consume on Chiloé is the fuel that makes their long-distance migration possible. Each spring, Hudsonian Godwits from three primary wintering areas at the tip of South America: Chiloé Island, Bahia Lomas, and Punta Rasa, begin to migrate north. They’ll make a brief stop in the central United States, before completing the journey to their Arctic breeding grounds at James Bay, the Mackenzie River Delta and in south-central and western Alaska.
In mid- to late summer, after their chicks have fledged, they leave their breeding grounds to return south, and this is where the real mystery begins. The birds don’t take the same path back. A full two to four months pass before they begin to show up back at their wintering grounds. This time span leads scientists to believe that they must be stopping over somewhere. Figuring out where the birds stop is the top priority for the team, and critical information for the conservation of the species.
[Nate] I like to think about stopover sites in terms of what humans need when they’re on a cross-country trip. You wanna have food, you wanna have a nice place to rest, a quiet place so that you can get up and go the next morning. And if they get all of that in a stopover site then they can continue on with their migration, but if they don’t it can cause major problems for the species.
[Narrator] Barely the size of a softball with a sinewy frame and matchstick-thin legs it’s hard to believe that Godwits migrate as far as they do. But watch them fly, and you quickly realize that these birds were designed to travel long distances.
[Nate] You know they, they’ve got endurance, they’ve got speed and agility, it’s really the complete package. What I love is watching them morph into different shapes, it’s like one super organism almost, and they just look so effortless. It really makes you realize that as humans, we’re pretty rooted to the ground. Sure we can jump in an airplane, but not in the same manner that these Godwits are able to jet around the world.
[Narrator] Back on the ground Nate and Chilean conservationist Luis Espinosa scout the mud flats for the places where these Godwits will touch down, locations where the team will have the best chance at catching large numbers of birds.
[Nate] Looks like it might be a roost spot. It might be worth walking down there. So what we’ve been doing over the past couple weeks has been scouting out sites and trying to document exactly where large numbers of Godwits are roosting or spending the high tide hours.
[Narrator] Roosts, where birds rest, make the best capture sites, and on Chiloé Island, a roost is no small matter.
[Nate] You can have as many as three or four thousand Hudsonian Godwits all together in one roost site at high tide. That really provides us with the perfect opportunity to capture a large number of them at once.
[Narrator] With the best location scoped out, it’s time for the team to do what they came here for: catching and tagging birds.
[Nate] Here on Isla Chiloé this year we’re using cannon nets, and that’s really just as it sounds.
[Narrator] Employing explosives, cannons, and projectiles to capture wild animals is potentially dangerous, and it requires planning and precision to ensure that the birds don’t get injured. The idea is to have the incoming tide slowly push the birds towards the front of the net, or ‘capture zone’. The net needs to be placed just above the high tide line, close enough to catch birds but far enough away so as not to get swamped.
Once they determine where to place the net the team jumps into gear, working together to get it set. The thirty-meter net needs to be first untangled and furled so it will shoot out smoothly. At each end and in the center, holes are dug for the three cannons. This labor-intensive task is an important one. In fact, positioning the cannons is the most critical step in the entire process. It can mean the difference between injured birds and a safe catch. The projectiles are placed. The cannons are wired back to a trigger box and then it’s all hands on deck to help disguise the net with a mixture of seaweed and sand. Even footsteps are camouflaged. If done properly, the birds will never know the net is there.
The final touches are put in place, but if the weary Godwits are going to move into the capture zone, the team needs to move quickly to their hiding position, well out of the capture area. Wild birds are anything but predictable, but the team is prepared to stick it out, and they know that their patience will eventually pay off. The situation improves quickly, and within minutes dozens of Godwits fly into the capture zone and move closer to the net.
[Nate] Three, two, one, fire! The scientists go crazy because everybody’s been sitting there eagerly anticipating are the birds gonna be in the right spot, are we gonna, is the net actually gonna fire correctly, and so when that net goes off and we see there are birds there, there’s a little bit of euphoria, a little bit of craziness, and a lot of relief. Always exciting.
[Narrator] It’s a good catch but no one can afford to relax until they’ve got all the birds safely removed from under the net. Everyone takes as many Godwits as they can carry.
[Nate] You can’t complain about catching another 50 birds and no injuries, everybody’s safe, so it went real well.
[Narrator] With all the birds move safely into keeping cages, the team assembles into a quiet circle to begin processing them. Finally the scientists can take a moment to examine these remarkable birds up close.
[Nate] This particular bird has not yet completed its primary molt. When you look at these these wings, they’re built for flying a long ways. That guy is built for speed.
[Narrator] Around the circle different stations are set up for collecting specific data. Measurements of the legs, wings, and bills.
[Nate] We’ll weigh the bird and then finally we’ll take some blood and a couple of feathers from their breast to use for genetic work.
[Narrator] But the most important step in the entire process, and the main reason the team is on Chiloé, is to get these birds banded.
[Nate] We’ll place a numbered band on them, a little metal band, so that if they’re ever recaptured anywhere else in the world, someone will know that they were captured in January of 2008 on Isla Chiloé. We’ll put another colored band just to tell us which year it was banded in.
[Narrator] But the most significant band is the lettered red flag placed on the bird’s left leg.
[Nate] It’s really an incredibly powerful yet simple tool. Those bands give each of these birds a recognizable sort of identity, so that we can walk out here on the beach and go, aha! there’s AC or A1, and we know exactly when we caught that bird, we know how much it weighed when we caught it, and then we can assess through time how that bird might grow, or how many years it might survive for, so it really allows us to tell the story of the bird.
[Narrator] Five days and 150 birds later, the team has furthered the effort to establish a marked population of Hudsonian Godwits. These tagged birds represent the first steps in an evolving process that over time will allow scientists to follow the Hudsonian Godwits’ annual migration.
[Nate] I’d love to, at the end of this project, to be able to say, here are the different places that Hudsonian Godwits stop on their migration, and then to be able to say, here the things that we really need to conserve in order to make Hudsonian Godwits a species that’s gonna be around for the next fifty to a hundred years and hopefully forever. Doing pretty well.
[Special Thanks To: Jim Johnson, Nathan Senner, Larry Niles, Luis Espinosa, Lee Tibbitts, Humphrey Sitters, Brad Andres, Amanda Day, Jorge Valenzuela]
[Produced by the Cornell Lab of Ornithology and Hobart and William Smith Colleges through the Crossing Boundaries Project]End of transcript
How do you conserve what you can’t follow? Nate Senner, a former Cornell graduate student, studies one the most accomplished migrants on earth, the Hudsonian Godwit. Although we know that godwits summer in Alaska and Canada and winter in South America, the entire population disappears for a few months during migration. They can’t keep flying for months on end, so where do they stop over? Nate is trying to fill in the gaps of our understanding by continuously tracking the birds using data loggers fastened to their legs. These devices will help him determine which stopover points godwits depend on to rest and refuel during their hemispheric jumps. He hopes to use this information to jumpstart conservation efforts to protect these sites, and the birds.