Texas A&M: Improving Macaw Chick Survival Using Foster Parents

An overwhelmingly successful chick fostering experiment conducted by the Texas A&M University College of Veterinary Medicine & Biomedical Sciences’ (CVMBS) The Macaw Society will greatly improve the number of scarlet macaw chicks that survive and fly away from their nests each year.

Gabriela Vigo-Trauco, a CVMBS postdoctoral research associate and co-director of The Macaw Society, has spent the past decade studying scarlet macaws’ nesting behavior and refining a new system for introducing chicks to foster parents.

Vigo-Trauco’s interest in macaws began as a young child, but her interest in the survival of macaw chicks, specifically, began during her last year of college at the Universidad Nacional Agraria La Molina in Lima, Peru.

“I started studying the behavior of macaws in Tambopata and saw that they don’t feed all of their chicks the same amount of food and that they don’t give them the same amount of parental care. They would favor the first chick, give less to the second one, and pretty much ignore the third and fourth,” Vigo-Trauco said. “This created a brood in which the first chick survived to fledge, the second one died sometimes, and the third and fourth ones never survived.”

Her research, done in collaboration with CVMBS associate professor Donald Brightsmith and Rony Garcia-Anleu of Guatemala’s Wildlife Conservation Society, was published in Diversity. It was part of Vigo-Trauco’s dissertation for her Ph.D. in wildlife and fisheries sciences awarded in May 2020.

“My big question was, ‘For those chicks being discarded by nature, how can I recover them and put them back in the population to try to increase the macaws’ numbers?’” she said.

She began her work by installing cameras in man-made macaw nesting boxes to monitor the macaws’ interactions with their chicks.

two scarlet macaw chicks
Scarlet macaw foster siblings.
Courtesy of Nora Magonyi
After determining that a lack of food was not the cause of the birds’ behavior, Vigo-Trauco realized that as the time between when the first and second chicks hatched grew longer, it became less likely that the parents would care for the chicks equally.

Building off a study done in Guatemala, she developed the idea of removing the second chicks from their nests and giving them to a different set of macaw parents that would be willing to care for them, either because they lost their own chicks to predation, poachers, or natural factors or because their chicks were already grown enough to need less care.

“When the second chick hatches four days after the first, it was more than 80% likely to die of starvation,” she said. “I would collect these chicks and raise them in our research center for 22 days or until they opened their eyes. Then, we placed them in different nests. In normal conditions, that chick would have died, but after I placed it back in a nest, it survived to fledge.”

Vigo-Trauco recalls initially being nervous that the foster parents would ignore or even attack the new chick. But by the end of the project, her team placed 28 chicks into new nests and saw every one accepted by its foster parents.

“I was not ready for such a great acceptance,” she said. “If it had been over 50%, I would have been super happy and said that the technique had potential. But our report was so good that it was a really big, happy success.”

Determining the details of this technique took years of research and trial and error, plus input from avian experts at Texas A&M and beyond.

It also required an army of “guacamayeros,” or macaw assistants, to help with climbing trees, nest observations, and working with the chicks.

“We integrated three separate fields — parrot ecology, avian veterinary medicine, and aviculture (the breeding of birds) — to come up with little tricks to make the techniques work better in the field,” Vigo-Trauco said. “It was really interesting because when you are trained in parrot ecology, you are trained to watch, let nature be, and take notes, but a veterinarian is trained to act and try to save the chicks. With the integration of the three fields, we came up with a really nice plan.

“As an example, because the aviculture people knew it would take time for a chick that had been hand-raised to learn how to beg for food, we decided that we would give the chicks supplemental food for their first 10 days in the foster nest,” she said.

Once the chicks were accepted by their foster parents, they were raised with the same care and attention as the parents’ birth chicks. While a few chicks died from external causes (predation and lightning), all of the other foster chicks went on to fledge and fly free with their foster parents.

As The Macaw Society begins sharing these successful results with colleagues in Central and South America, Vigo-Trauco looks forward to continuing to apply the research she has devoted so many years of her life to.

“It was a really intense project, especially because I had a baby in the middle, but to have the paper published is very, very rewarding,” Vigo-Trauco said. “It’s really wonderful to feel like all of my research and investment in taking the data is going to be applied to real conservation.

“It was an extra plus that I was able to study a species I really love and take my daughter to the rainforest to see me climbing trees and waking up at 4 a.m. to go check macaw chicks,” she said. “I was able to show her, in real life, how to accomplish what you really want to do.”