Cholao, a small Lesser Yellowlegs (Tringa flavipes) is turning into a well 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 presently positioned 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 concerning 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 hen, however the flights of 34 different “tringas”, as they’re informally known as. We requested him some questions obtained from our social media followers, and his solutions are usually not solely fascinating, however give a tremendous image of the epic travels migratory birds do.
How did the monitoring of those migratory birds get began, and why deal with the Lesser Yellowlegs quite 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 likely one of 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 larger sustainability of this crop by means of rotation with rice. And through that course of, we seen 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 all the time used the identical monitoring expertise, or has it modified over time?
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 in addition establishing the infrastructure on this area to have the ability to monitor them. In actual fact, of the primary 10 tringas we captured, throughout an train we did with Selva, a Colombian conservation group, we by no means knew once they left the nation, as a result of once we tagged them, we did not have any Motus stations within the Cauca Valley.
Motus has been the expertise wherein we’ve got invested essentially the most time and sources to trace the tringas. However this expertise has an ideal limitation: it solely works the place there’s community protection—which is excellent in the US, in sure nations in northern South America, similar to 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 may 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 got tagged —about 30— as soon as they go North Dakota we have no idea the place they go. That’s why, since final yr, we began utilizing satellite tv for pc transmitters, which give us a greater concept 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 observe the identical migration route annually, each on their approach north and on their return to the Cauca Valley? How predictable are Lesser Yellowlegs?
I do assume there are some patterns of their routes. We’ve tagged about thirty tringas with radio transmitters which are detected by the Motus community. And we’ve got put satellite tv for pc transmitters on 5 extra. What we have seen, usually, is that throughout the spring migration, within the months of April and Could, birds appear to be in a race to achieve 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 nearly a straight line by means of all of the central states of the US. However as soon as they cross the northern border of the US, 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 be a part of their nesting areas.
Within the fall migration, there’s extra variability: some undergo the central states and make stops alongside the way in which, in all probability gathering meals and power. Others take some attention-grabbing detours: we’ve got had tringas that enter by means 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 means of the center of the nation and find yourself in Kentucky, Tennessee, South Carolina, and depart by means of Florida. Nonetheless others come down the identical route we have detected them utilizing throughout 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 skilled, and I do not know if it has been established whether or not they journey in household teams or not, however I might wish to know. What we do know is that in each the spring and fall migration routes, earlier than making these large leaps, there are intervals wherein they attempt to retailer up as a lot power as attainable by means 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 power. Then it went to Iowa, to a giant swamp that probably has plenty of meals right now of yr. 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 lots of birds seemingly understand them as the complete arrival of spring, a sign to begin the breeding cycle and different actions related to that season. But it surely’s not, after these days, a frost hits, the birds undergo, and nests, together with the power invested in breeding, are misplaced.
Migration requires a large amount of power. 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 skilled in migration ecology, I can say that, usually 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, similar to raptors, that may cease throughout their migratory route and sometimes feed within the areas they go by means of. However many migratory birds merely depend upon these power reserves collected of their fats, particularly if they’re crossing the ocean and have nowhere to cease to eat. In fact, as soon as they land, which is called “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?
Primarily based on what we’ve got recorded, at the least of their crossing of the ocean and relying on elements similar to wind and climate, they common 25 to 30 miles per hour.
How is that this knowledge helpful to us, and the way does it mirror in decision-making?
It gives us with the knowledge 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 extremely vital as a result of it permits us to determine the stopover websites of migratory birds, what some name “eating places” and “resorts”. When we’ve got 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 knowledge offered by the GPS may 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 knowledge we’re receiving is overwhelming, spectacular!
What’s the tools the hen carries like?
For each Motus transmitters and those who use satellite tv for pc positioning, the kind of transmitter is similar: a tiny backpack worn on the hen’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’s all the time a priority that they might all of the sudden impression hen mortality, not a lot as a result of they make them extra enticing as prey, however as a result of the harness can restrict mobility, if it’s not fitted accurately. That’s the reason solely educated personnel deal with the set up.
One other issue is that migration carries an power price and people two grams could make a giant distinction. In most species which are studied for migration, the intention 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 consider placing satellite tv for pc transmitters on a hen 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 got managed to trace a single particular person is 2 years. It’s believed that this occurs resulting from put on and tear of the harness, which is manufactured from nylon and falls off.
With the information collected to date, what has shocked you?
I hoped for a stronger affiliation between the tringas and pure habitats. That is what you’ll think about, that they might 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 deal with implementing bird-friendly practices within the Cauca Valley, the place these rice crops are a key piece of the migratory puzzle.
