Latest News | The first pilpilén chicks in five years are born in the Maipo River wetland.

In the park, they built fences to protect the nests from foxes and stray dogs, their main threats.

Although they were born in late summer, the Río Maipo Wetland Park preferred to wait until their first three Common Pilpilén chicks were a little older before announcing the news. “The chicks take 45 days to begin flying. Before that, they are under the care of their parents and are very vulnerable to local birds of prey, such as the Kestrel, the Dancer’s Warbler, and the Nuco, and of course, the Fox. All of them attack them at night,” explains Nicole Morales.

Nicole is one of four park rangers at this wetland, declared a nature sanctuary in 2018 by the Municipality of Santo Domingo and managed by the Cosmos Foundation. The 60-hectare park is located at the mouth of the Maipo River, next to the port of San Antonio, and is home to 180 resident and migratory bird species, along with specimens of the Chilla fox.

“There isn’t much information about these 180 species, which is why the work of the park rangers is so important,” emphasizes Diego Urrejola, executive director of the Cosmos Foundation. “We focused on the Pilpilén because it’s a threatened species within our ecosystem. For some reason we’re investigating, five years ago this bird was unable to breed on the south bank of the Maipo River,” he adds.

Trial and error

The path to getting the pilpilenes to reproduce hasn’t been easy. “We’ve been learning through trial and error. We’ve been discovering and isolating the factors that prevented chicks from hatching for five years,” says Urrejola.

The park’s executive director lists the areas where they began working: “When we arrived, it was easier to see cows than birds. We used fences to keep out the cattle and prevent cars from accessing the beaches. There was a lot of kitesurfing, which is very harmful to birds, and we excluded them. We’ve been educating fishermen not to leave their waste.”

Added to this is the proximity to the port of San Antonio. Cranes are visible in the background of the park’s landscape, while the noise of ship horns interrupts the birds’ songs. Still, he says, the greatest threat to the pilpilenes is another one that at first glance seems harmless.

“Free-roaming dogs are a big problem for birds: they eat eggs and chicks, they chase birds. It’s also been a task of educating the community so they understand that they can’t come here for walks with their dogs, and that they can’t let them roam alone without supervision,” he explains.

Nests with fences

Two years ago, the wetland took a new step in its work to preserve the pilpilén. With the support of the Santo Domingo municipality, the Banco Santander Huella Program, PiCparks, and the Chilean Bird Watchers Network, they dedicated themselves to the task of protecting their nests.

“Foxes are also a significant threat, but we can’t remove them because it’s their natural habitat and it would be an intrusion. After several trials and errors, we created a fence that encompasses up to three nests, giving the pilpilenes enough space to land and take flight. The sticks are protected with netting and buried deep enough so that the foxes can’t dig or jump,” Urrejola explains.

At the same time, they began a bird banding process. “We put numbered rings on their legs, which give us an idea of where they’re moving and what they’re doing. The pilpilenes are territorial. They pair up and nest on the beach, but they need three meters of space from other nests. We presume there’s migration between nearby wetlands,” he adds.

They also began monitoring the foxes’ movements. “We put radio telemetry collars on them, which emit a signal picked up by a radio and allow us to detect their location. This has allowed us to discover that during the pilpilenes’ breeding season, between September and March, the foxes come down to the beach at night looking for nests, while during the day they roam other areas of the park and its surroundings,” he explains.

With these first three births, Urrejola believes the project to preserve the species is working. “In a healthy ecosystem, the balance is between the large number of births versus predators,” he argues, reinforcing the importance of continued reproduction.

“The pilpilén lives between 20 and 30 years. Because it’s a fairly long-lived bird, it took a while to give it a more urgent conservation status, so the population decline will be seen when there are no more individuals left alive. What has been achieved in this park is encouraging,” observes Nicole Morales.