More than 50 years ago, the ariel toucan was reintroduced to Tijuca National Park, the world’s largest urban forest, located in Rio de Janeiro in southeastern Brazil. Now, a new study finds that the bird, which became locally extinct in the 1960s, has almost entirely settled back into its original role in the ecosystem, serving as a critical species for forest restoration.
Researchers tracked ariel toucans (Ramphastos ariel) through the Tijuca forest for a full year, logging every plant species it consumed compared with a list of 101 native plant species the bird had historically interacted with.
The research team often walked more than 20 kilometers (12.4 miles) a day through the forest observing the toucans’ dietary habits. They found that the bird, recognized for its colorful feathers and signature black beak, had interactions with at least 76% of the plants historically on the menu for ariel toucans.
“They are such sociable and intelligent beings. The way they are able to handle fruits: Sometimes it has a hard capsule on the outside, and they hold it with their little feet and open it with their beaks,” lead author Flávia Zagury, an urban ecology researcher at the Federal University of Rio de Janeiro, told Mongabay by phone. “They have an incredible ability to access these resources.”
They were observed feeding on the fruits and seeds of plants that few other animals can crack open, potentially making them key dispersers for endangered trees, including the jussara palm (Euterpe edulis) and the bicuíba-branca (Virola bicuhyba). Both are native trees nationally classified as endangered and have lost more than half of their range.
“The jussara palm, a species in danger of extinction, was one of its favorites. I think it was the champion, the one it ate the most,” Zagury said.
Other recently reintroduced animals include red-rumped agoutis (Dasyprocta leporina) and brown howler monkeys (Alouatta guariba). Researchers found minimal dietary overlap with the toucans, indicating that the birds hold a “functional uniqueness” in the park’s ecosystem, particularly in relation to plants with larger seeds, Zagury added.
While toucans interacted with 76% of the plants on the full list, they interacted with nearly 90% of the plants that have medium and large seeds, more than 6 millimeters (0.2 inches).
The ariel toucan was reintroduced in 1970, when primatologist Adelmar Coimbra Filho released 46 individuals inside Tijuca park as part of an effort to restore fauna in the degraded forest. Since then, the released birds had been left largely unmonitored.
The new study is among the first to evaluate the reintroduction more than half a century on. Zagury said a lot remains unknown, including how much the ariel toucans contribute to the dispersal of different plant species and reforestation. “It’s pretty much a blank canvas; there is so much we still don’t know,” Zagury added.
Banner image: Ariel toucans in Rio de Janeiro, Brazil. Image courtesy of Flávia Zagury.
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