Five large forests in Central America, stretching from southern Mexico to northern Colombia, are essential vital corridors for dozens of species of migratory birds, revealed a scientific team that analyzed millions of records made by bird watchers on the eBird platform, one of the largest participatory scientific databases in the world.
The study promoted by the Wildlife Conservation Society (WCS) and the Cornell Laboratory of Ornithology (Cornell Lab) identified that these forests support between 10 and 46 percent of the world’s populations of 40 species of birds that breed in North America and spend the boreal winter in Latin America and the Caribbean.
A representative case is that of the cerulean warbler, a species that has declined by 70 percent since 1970. “More than 40 percent of its global population passes through these forests during spring migration,” said Viviana Ruiz Gutiérrez, leader of the Conservation Science Program at the Cornell Laboratory of Ornithology and co-author of the publication.
The forests to which this research refers are Selva Maya, from Mexico, Belize and Guatemala; the Moskitia, of Honduras and Nicaragua; Indio Maíz-Tortuguero, from Nicaragua and Costa Rica; La Amistad, from Costa Rica and Panama, and Darién, from Panama and northern Colombia.
One of the relevant findings of the work is that these sites have a key link with the forested areas of the northeastern United States, Ontario and Quebec, Minnesota and Wisconsin, the Mississippi Delta and the Appalachian regions, as well as the mountainous region of Texas, where the species reproduce.
“Our results show the role of the five great forests of Central America as a reference point for the conservation of migratory birds,” says the work published in Biological Conservation.
“When you see a map of Central America and imagine the birds flying over the region 50, 100 years ago, all that was green. But now, these forests look like green patches, islands, in a sea of urbanization and agriculture,” said Ruiz Gutierrez.
And he added: “Without these forests, the birds would have nowhere to stop, they would not have that protection to spend the winter season and then go back to the United States to breed.”
To carry out this research, more than 2 billion bird observations submitted by more than one million people were analyzed to eBird, a global participatory science platform developed by the Cornell Laboratory of Ornithology that brings together millions of records contributed by people around the world.
Ruiz Gutiérrez stated that, through verification tools and advanced machine and statistical learning models, they transformed eBird reports into high-resolution distribution maps, abundance estimates and migratory patterns.
“Having access to millions of data and analyzing them has generated information as important as that of the article,” said the scientist.
When asked about the weaknesses of eBird, the researcher mentioned that areas without population or where there are no people who are trained to upload records to the platform are the biggest limitation.
“We have difficulties in sighting seabirds; in those cases, sometimes people go on a fishing boat or on a cruise ship, and that is when we have records, but there is still a big gap in those regions.”
The researcher stated that the main purpose of this work is to promote international cooperation in conservation. “If someone enjoys seeing warblers in Central Park in New York, in the United States, or wants to continue observing birds in the forest near their home in Canada, they should understand that this is only possible thanks to the people who, day after day, protect these habitats in the south.”
The report mentions that despite the relevance of the five forests of Central America, they have been reduced between 5 and 30 percent since 2000, mainly due to illegal livestock farming. “We are at a critical point. If this deforestation continues, millions of birds will disappear,” he commented.
In North America, 2.5 billion migratory birds of 419 species have been lost since 1970.
In this context, Ruiz Gutiérrez spoke out to strengthen conservation efforts in local or indigenous communities through multi-year financing that comes from northern countries, in order to encourage the regeneration of these forests, sustainable management and agroforestry.
“Sometimes we don’t directly perceive how the loss of these habitats affects us or understand the magnitude of these connections. We know that birds come and go, but we don’t always understand what that means for our environment. That is exactly what we need to communicate better and what I hope this study will help make visible.”