Cholao, the amazing Lesser Yellowlegs that gives wings to GPS monitoring across the Americas

Cholao, a small Lesser Yellowlegs (Tringa flavipes) is turning into a widely known character amongst Audubon’s social media followers. Why? Due to its migratory journey, which began within the Cauca Valley, in southwestern Colombia,  and just lately reached the boreal forests in Canada, was monitored with a GPS that tracks its whereabouts, its motion, its epic crossing over the Gulf of Mexico till touching down in Louisiana, and from there  to  Saskatchewan, Canada, the place it’s at present situated and can absolutely stay.

Jorge Velásquez, Audubon’s Science Director for Latin America and the Caribbean, is probably the one who is aware of essentially the most in regards to the life and travels of Cholao —who is not only one, however a number of people— as he has spent some years monitoring not solely this particular chicken, however the flights of 34 different “tringas”, as they’re informally known as. We requested him some questions acquired from our social media followers, and his solutions are usually not solely fascinating, however give an incredible image of the epic travels migratory birds do.

How did the monitoring of those migratory birds get began, and why give attention to the Lesser Yellowlegs slightly than one other species?

We started monitoring the actions of Tringas flavipes within the Cauca Valley, Colombia, in April 2022. The curiosity on this species is as a result of it is among the shorebirds with the best decline in its populations; as well as, it’s a species related to one of many emblematic crops —sugar cane— in one of many areas the place we’re working essentially the most, such because the Cauca Valley.  

We are attempting to advertise higher sustainability of this crop by way of rotation with rice. And through that course of, we observed that this was a species that used them with a sure frequency. This sparked our curiosity in studying extra about whether or not these populations stayed on this place all through the winter, their densities and, above all, the place they got here from, what challenges they confronted throughout their journey from their nesting areas to the Cauca Valley.

Have you ever at all times used the identical monitoring know-how, or has it modified through the years?

They’ve  modified! We began with Motus stations and it is vital to say that there weren’t any within the Cauca Valley. Monitoring the actions of those tringas was not only a matter of becoming them with radio transmitters but additionally establishing the infrastructure on this area  to have the ability to monitor them. Actually, of the primary 10 tringas we captured, throughout an train we did with Selva, a Colombian conservation group, we by no means knew after they left the nation, as a result of after we tagged them, we did not have any Motus stations within the Cauca Valley.

Motus has been the know-how during which we’ve invested essentially the most time and sources to trace the tringas. However this know-how has an incredible limitation:  it solely works the place there may be community protection—which is superb in america, in sure nations in northern South America, reminiscent of Colombia, and in Central America. However as soon as the birds cross the border into Canada, particularly within the central a part of the continent, Motus protection could be very poor.

Does that imply we do not know what occurs to them?

In all these years of monitoring the birds that we’ve tagged —about 30— as soon as they go North Dakota we have no idea the place they go. That’s why, since final 12 months, we began utilizing satellite tv for pc transmitters, which give us a greater thought of native actions. Now, we’re ready to see if Cholao and his friends can lastly present us the place they’re nesting.

Do these birds comply with the identical migration route every year, each on their approach north and on their return to the Cauca Valley? How predictable are Lesser Yellowlegs?

I do suppose there are some patterns of their routes. We’ve tagged about thirty tringas with radio transmitters which can be detected by the Motus community. And we’ve put satellite tv for pc transmitters on 5 extra. What we have seen, typically, is that through the spring migration, within the months of April and Could, birds appear to be in a race to succeed in their nesting grounds within the boreal area of North America. So, on that journey, they use essentially the most environment friendly route attainable, the Central American migratory hall or Midcontinent Flyway, which is sort of a straight line by way of all of the central states of america. However as soon as they cross the northern border of america, we have no idea what occurs, whether or not they proceed in a straight line or if a few of them journey to Alaska, which can also be a part of their nesting areas.

Within the fall migration, there may be extra variability: some undergo the central states and make stops alongside the way in which, in all probability gathering meals and vitality. Others take some attention-grabbing detours: we’ve had tringas that enter by way of Minnesota and North Dakota within the U.S. Others go all the way in which to New York and are available down the East Coast. There are additionally tringas that come down proper by way of the center of the nation and find yourself in Kentucky, Tennessee, South Carolina, and depart by way of Florida. Nonetheless others come down the identical route we have detected them utilizing through the spring migration. It’s extremely variable.

May it’s associated to group journey? Do they fly down as a household?

I am not an professional, and I do not know if it has been established whether or not they journey in household teams or not, however I might prefer to know. What we do know is that in each the spring and fall migration routes, earlier than making these large leaps, there are durations during which they attempt to retailer up as a lot vitality as attainable by way of a little bit of a feeding frenzy, each earlier than and after.

That’s what we noticed with Cholao, which is tagged with GPS: it made virtually a two-and-a-half-day uninterrupted journey between Cali and the Louisiana coast. As quickly because it arrived in Louisiana Cholao spent a few week in a single place, I think about recovering from the journey, feeding and gathering vitality. Then it went to  Iowa, to a  giant swamp that presumably has a number of meals right now of 12 months. After which, as much as Saskatchewan, Canada.

May local weather change be influencing their timing and routes?

Maybe what they name “false springs”. March or April arrive, bringing an increase in temperatures, and plenty of birds seemingly understand them as the total arrival of spring, a sign to begin the breeding cycle and different actions related to that season. However it’s not, after these days, a frost hits, the birds endure, and nests, together with the vitality invested in breeding, are misplaced.

Migration requires a large amount of vitality. Cholao’s followers ask if the Yellowlegs eat alongside the way in which or how they handle to face up to the trouble.

With out being an professional in migration ecology, I can say that, typically phrases, what occurs with most migratory birds is that within the weeks earlier than beginning a migration, they feed frantically to extend their fats reserves as a lot as attainable, which they depend on for the journey. There are some species, reminiscent of raptors, that may cease throughout their migratory route and sometimes feed within the areas they go by way of. However many migratory birds merely rely on these vitality reserves amassed of their fats, particularly if they’re crossing the ocean and have nowhere to cease to eat. After all, as soon as they land, which is named “stopover”, they feed as soon as once more. They usually make their final leap to their breeding areas.

One other fast reality about Cholao: how briskly do they fly?

Based mostly on what we’ve recorded, no less than of their crossing of the ocean and relying on elements reminiscent of wind and climate, they common 25 to 30 miles per hour.

How is that this information helpful to us, and the way does it replicate in decision-making?

It offers us with the data wanted to later outline protected areas or to create campaigns in favor of conservation or just to maintain as a repository for research. 

For the Motus community, it is rather vital as a result of it permits us to determine the stopover websites of migratory birds, what some name “eating places” and “lodges”. When we’ve thirty, fifty, or 100 tagged people, we begin to see that sure areas are extra closely used, important websites on the migration route of sure species. This, in flip, permits us to determine the threats these locations face, enabling organizations like ours, devoted to the conservation of birds and their environments, to handle actions to face these threats. 

It’s equally helpful on a extra native scale, the place information supplied by the GPS could be very helpful. It goes into such element that we are able to pinpoint precisely which lands, rivers, or particular crops the tringas use within the Cauca Valley, and the way they spend their time  there. The quantity of data we’re receiving is overwhelming, spectacular!

What’s the gear the chicken carries like?

For each Motus transmitters and those who use satellite tv for pc positioning, the kind of transmitter is identical: a tiny backpack worn on the chicken’s again, the place solely the form and weight varies a bit. The Motus transmitter is a bit flatter and lighter, weighing lower than two grams, whereas satellite tv for pc ones weigh two grams.

There may be at all times a priority that they might instantly affect chicken mortality, not a lot as a result of they make them extra engaging as prey, however as a result of the harness can restrict mobility, if it’s not fitted accurately. That’s the reason solely skilled personnel deal with the set up. 

One other issue is that migration carries an vitality price and people two grams could make a giant distinction. In most species which can be studied for migration, the goal is to maintain the transmitters beneath 3% of the person’s physique weight. Till a couple of years in the past, it was inconceivable to think about placing satellite tv for pc transmitters on a chicken like Cholao, on a tringa, as a result of they have been all too giant, however that is not the case anymore.

And what’s the lifespan of those transmitters? How do they work?

Each kinds of transmitters, GPS and Motus, use daylight to supply energy. Within the case of the Motus, they’ve a battery that recharges with daylight, making them just about everlasting, identical to the satellites. Nevertheless, the longest we’ve managed to trace a single particular person is 2 years. It’s believed that this occurs as a consequence of put on and tear of the harness, which is made from nylon and falls off.

With the information collected to this point, what has stunned you?

I hoped for a stronger affiliation between the tringas and pure habitats. That is what you’ll think about, that they’d go to pure wetlands or, within the Cauca Valley,  focus across the Sonso lagoon or the Cauca River. However no! The affiliation of the Lesser Yellowlegs with rice crops is unimaginable, and they’re virtually there, or will get there, wherever there’s a rice crop. This implies we’re heading in the right direction, and we should give attention to implementing bird-friendly practices within the Cauca Valley, the place these rice crops are a key piece of the migratory puzzle.