Scarlet macaws abandon their youngest chicks

Picture a rainbow of feathers fluttering from the treetops. That’s a scarlet macaw, a bird known for its love and loyalty. However, as perfect as scarlet macaws seem, these lifelong mates often abandon their chicks.

A study conducted by researchers at Texas A&M College of Veterinary Medicine and Biomedical Sciences has revealed that scarlet macaws tend to show favoritism with their young, a cruel twist in their nature.

Scarlet macaws have favorite chicks

Scarlet macaws, even with bountiful resources, deliberately withhold feeding the youngest of their chicks. This stark bias results in only one or two chicks learning the ropes of survival, without consideration for broods that host up to four chicks.

“Scientists have known for years that scarlet macaws hatch more chicks than they fledge,” said Dr. Donald Brightsmith, a professor in the VMBS’ Department of Veterinary Pathobiology.

“We found that 26% of second chicks in scarlet macaw broods and nearly all third and fourth chicks die before fledging.”

Perplexing, isn’t it? How could such loving creatures abandon their own young to die? It seems, in this case, the parental code for these birds isn’t written in black and white.

Survival of scarlet macaw chicks

Dr. Gabriela Vigo-Trauco, a leading researcher with the Schubot Center for Avian Health, noted a relevant fact – every chick doesn’t hatch on the same day because scarlet macaws lay eggs over an extended period.

The difference in the hatching dates influences the feeding decisions of the parents – a survival tactic no one saw coming.

When the hatching period varies by four or more days, the parental care for each chick starts differing. This differentiation is what leads to the appalling neglect and subsequent starvation of the youngest chicks.

Foster parents for macaw chicks

With these findings, Texas A&M scientists have devised a means to combat this issue, mitigating the fatalities among the neglected chicks.

The researchers propose that “foster parents” for the neglected chicks might be the solution to this pressing problem. While this may seem like a human intervention, it’s more akin to a nudge in the right direction.

The scientists believe that foster parenting strategies could come to the rescue of many endangered parrot species, shifting the balance in favor of these threatened birds.

Brood reduction: A harsh Reality

The strategy these birds employ is termed “brood reduction,” and it isn’t exclusive to scarlet macaws. Many bird species, including sea birds like boobies, gulls, and eagles, are notorious for their sibling rivalries and fratricide.

For scarlet macaws, however, starvation is the cause of 45% of all chick deaths, with the third and fourth hatchlings in a brood rarely surviving.

What could be the reason behind 26% of second-born chicks also perishing from lack of food? The researchers tackled this question head-on. They started by rejecting the idea of resource scarcity causing starvation.

Gustavo Martinez, a member of the research team, investigated the scarlet macaw’s primary food source – fruit trees – in the forests of the Tambopata National Reserve in Peru.

Martinez found that the abundance of food in the environment was not a problem. So what was the real issue?

Disturbing pattern of neglect

To find out, the researchers turned to modern technology, installing cameras in nest boxes across the Tambopata National Reserve. From their footage, a disturbing pattern of neglect emerged.

Dr. Brightsmith noted that scarlet macaws have a food sac on their necks called a crop, and in chicks it’s very easy to see when it’s full of food.

“We caught video of female macaws trying to over-feed their oldest chicks while the third chick would be running slowly around the base of the nest with an empty crop, begging for food,” said Dr. Brightsmith.

“What’s more, the chicks at that age can’t regulate their own body temperature, so they need to be in the nest. We saw that the mother won’t even share her body heat with her dying offspring.”

“As scientists, we try not to do what’s called anthropomorphizing – attaching human ideas about morality to animals. But it’s hard to watch that and not think of it as parental abuse.”

Saving neglected macaw chicks

While the evidence paints a grim picture, it’s not all doom and gloom. Remember the foster parent solution we talked about earlier? Well, it has been successfully implemented by Dr. Vigo-Trauco as part of her doctoral research.

“To save neglected chicks, they are raised in captivity for a few weeks before being placed in the nests of macaws with chicks at a similar developmental stage or that have lost all their chicks to predation,” explained Vigo-Trauco.

The success of the fostering program lies in ensuring that all chicks look approximately the same size. This familiarity encourages the foster parents to accept the orphaned chicks as their own.

Success of the fostering program

The good news? The scarlet macaws accept their new role with surprising ease. Despite their initial confusion, they accept and care for the newcomers. So far, the team has successfully re-homed 28 chicks across three breeding seasons.

While scarlet macaws aren’t endangered or threatened, their behavior sheds light on survival strategies that might prove crucial for other parrot species around the globe.

“Parrots are one of the most endangered groups of birds in the world,” noted Dr. Brightsmith. “We hope that this program, and the understanding of brood reduction behind it, can assist with the conservation of a broad array of parrot species across the tropics.”

The study is published in the journal Diversity.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–