Challenges of Great Green Macaws Reproducing in the Wild

Volunteer Blog: Pascal
February 8, 2024
Volunteer Blog: Friedemann
February 9, 2024
Costa Rica is a conservation leader, with 25% of the country designated to National Parks and Reserve territories to help protect biodiversity. Costa Rica is estimated to have half a million species, or five percent of the world’s biodiversity. It doesn’t sound like a lot until you consider how small of a country Costa Rica is!

The Great Green Macaw (GGM) is a majestic bird native to Costa Rica. The bird both nests and feeds on the mountain almond tree (Dipteryx panamensis) a towering tree that can grow fifty meters tall and up to 600 years old. Unfortunately, even with Costa Rica preserving so much land, the GGM and mountain almond trees are both endangered species, having suffered severely from deforestation and land use changes.

The mountain almond tree has been coveted for its precious hardwood and was intensively logged until the early part of this century (see). The diminished native habitat has diminished food sources and breeding habitat.

Macaws are so large, they are challenged to find appropriate natural cavities to make their nests. The mountain almond tree provides perfect conditions for both food and nesting habitat. However, the reduction of rainforest have led to the GGM being critically endangered.

Ara Manzanillo's first and foremost goal is to reintroduce and re-wild the GGM. Since initiating the assisted reproduction program, Ara Manzanillo has installed 27 nest boxes thirty meters high in selected trees to provide similar qualities of natural nesting cavities. In nature, GGM's chew at nests to stimulate reproductive hormones, so we include wood and coconut fiber in the nest boxes to be more comfortable and inspire "nesting".

The nest boxes have enabled the Ara Manzanillo team to monitor couples throughout the breeding season, and check on egg, and chick activity. Predation is very common in natural nests, though we have improved nest designs to mitigate predation by toucans, monkeys, snakes, and weasels.

There have been more natural nests sighted each year since reintroduction. Community involvement has provided important data such as the location of natural nests which we monitor whenever possible.

Dead snags naturally provide large, hollowed nest cavities, though pose problems for GGM’s and Ara Manzanillo staff alike. Dead trees are unstable and dangerous for humans to climb; drone footage is the only way to monitor in-cavity nesting. More importantly, dead trees fall.

Recently, a Mountain Almond tree hosting a natural GGM nest broke due to a strong wind. Trees in poor condition are in danger of natural weather occurrences taking them to the ground – a devastation for both the macaw chicks and parents.

The GGM’s s being at heightened risk for predation and unstable habitat has led us to opt for the use of artificial nest boxes. Placing nest boxes in safe, healthy trees have reintroduced over 80 macaws since the start of the program, to successfully fledge and integrate!

- Duaro Mayorga, Ara  Manzanillo Bird Specialist