To save scarlet macaws, scientists are rescuing chicks from their lethal parents

Scarlet macaws are an iconic but declining tropical bird. To change the species' fate, scientists are working to counter a lethal parenting method that dooms many chicks to death.

Parker hadn't even opened his eyes when a hand snatched him from his nest.

It was a Monday morning in November 2018 in the Tambopata National Reserve, deep in the Peruvian Amazon, and the featherless chick was frail and underweight, barely longer than a middle finger. He was the youngest of his four scarlet macaw siblings, and that meant he was almost certainly doomed to starve.

Standing at the base of the tree was Gabriela Vigo-Trauco, the Peruvian scientist who orchestrated this abduction.

By studying these birds for over two decades, Vigo-Trauco had discovered that scarlet macaws intentionally starve their youngest chicks. The scientist from Texas A&M University found that almost all third and fourth chicks in multi-egg nests don't make it, and around 25% of second-born chicks meet the same fate.

This brutal parenting approach was once a survival strategy. Now, it is a formidable constraint on recovery for this declining species – with poaching and logging already having driven one sub-species to near extinction across Mexico and Central America.

In 2017, Vigo-Trauco launched a rarely attempted form of rescue-mission, which led her to the chick she named Parker. Her goal was to recruit wild scarlet macaw couples to become foster parents for the doomed chicks. By persuading wild birds to take on the task, she hoped to test out a new lifeline for Peru's neglected offspring – and for the wider species.

Why do scarlet macaws neglect their youngest chicks?

Scarlet macaws are impossible to miss. Their crimson plumage stands out against the forest green, and you can hear their screeches long before you see them.

Each female can lay up to four eggs per season, but usually only one or two fly from the nest.

"The parents, particularly the mother, pushed [the youngest] away," says Vigo-Trauco, who is co-director of The Macaw Society, a Peruvian conservation organisation that first-revealed revealed this behaviour, after installing nest-cameras in 2007.

"The chick is cold and screaming, and when the father comes, he feeds the mother, the [first and second] chicks, and leaves the third one yelling away."

There was no sibling bullying, and no link to food availability. So why do the parents neglect their younger chicks?

Vigo-Trauco believes parents can't cope well with chicks at different development stages. Even four or five days between hatching can make a huge difference, with the resulting chicks requiring vastly different feeding regimes and even nest temperatures.

The parents are forced to choose, she says. If they stretch too much to feed them all, there's a risk none will make it.

How wild foster parents help

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