The Great Green Macaw (Ara ambiguus) is a large neotropical parrot whose distribution extends from Honduras, in Central America, to Ecuador in the South. The species is classified as endangered by the IUCN (International Union for Conservation of Nature), having declined by at least 50% in the last 50 years throughout its range (BirdLife International, 2016). The main factors contributing to the decline of Neotropical parrots are deforestation and poaching (Berkunsky et al. 2017).
Although there is a lack of information on poaching in Costa Rica, Great Green Macaws from Nicaragua and Honduras are known to be traded. In Costa Rica, the most recent evidence on nest poaching is reports of people asking community members for Great Green Macaw eggs (Collar 1996, Joyner & Portillo-Reyes 2018). Although poaching is a threat to the GGM population in the country, historical deforestation and the consequent habitat fragmentation have been to blame for the dramatic decline of Green Macaws, specifically during the 1980s and 1990s when habitat loss was estimated at around 90% (Chassot et al. 2005).
The impact of reduced habitat quality resulting from logging is unknown on the Green Macaw population, therefore, it is part of Macaw Recovery Network’s mission to investigate the scale of the different effects it has on habitat quality surrounding nesting sites. Compared to other endangered bird species, GGM is relatively poorly studied.
According to modern scientific literature, over the 28 years that the species has been studied, there have only been 380 articles, to which Costa Rica has contributed the most amount of studies on this species (Brightsmith, 2006).
Given the above, we will build on the knowledge base from the long-term baseline studies of the green macaw conducted by the Centro Científico Tropical (CCT) -Scientific Tropical Center-; which resulted in the CCT initiating programs to protect the Mountain Almond Tree, increasing community work and government support. These studies revealed the dependence of the Great Green Macaw on the Mountain Almond Tree (Dipteryx panamensis) to which it relates on two different levels, the tree provides a source of food and a site for nesting in its cavities. It is worth noting that although there are at least 37 known species that serve as food for the Great Green Macaw, it has a certain preference for the beach almond tree and the Titor (Sacoglottis trichogyna); the same is true for the nesting sites, although the Mountain Almond Tree is the preferred nesting site, Great Green Macaws have been found nesting in at least 4 more species among them: Caobilla (Carapa nicaraguensis) and Cativo (Prioria copaifera).
Costa Rica has a long history of environmental protection and cooperation; this provides the perfect environment for pioneering and innovative research, research that has been carried out by the Macaw Recovery Network for the last 3 years in collaboration with the Centro Científico Tropical.
Below you can see some facts and numbers from the 2019 – 2020 breeding season for the Great Green Macaw in terms of nesting sites:
- 10 new nesting sites were found with respect to 2018-2019.
- A total of 35 nests were monitored, of which 86% were active.
- It was observed that the GGM nested mainly in open sites, used for activities such as cattle ranching (paddocks) in most cases.
- It was observed that GGM preferred to nest in Dipteryx panamensis 88% of the time
- And that 73% of the trees of that species were found in pastures, which represents a high risk in terms of the departure of the chicks.
- A nesting site was recorded on a new tree species known as Ajillo (Balizia elegans), where there was only one nest.
- In addition, nesting sites already known to science were recorded for species such as Botarrama (Vochysia ferruginea), Cativo (Prioria copaifera) and Caobilla (Carapa nicaraguensis).
- The nesting of a pair in an artificial nest was recorded, this would be the first time that this happens for a pair of totally wild Great Green Macaws.
- Regarding the characteristics of the natural cavities of the nests, it was found that the entrance can be at heights between 16 and 32m (Σ 24.7 ± 5 m) above the ground. The size of the entrance to the nest cavity can also be very variable between 21 and 276 cm (Σ 58), with most measuring under 80 cm.
And as for the breeding data we have to:
- The monitored population in the study area lied its eggs for approximately two months (December and January).
- Of the 35 monitored cavities, 31 resulted in successful nests.
- In total, active breeding pairs laid 101 eggs; being 1 the minimum number of eggs
- The minimum number of chicks per nest was 1, the maximum was 3, and the most frequent amount, 2 chicks.
- The total number of chicks produced was 60. However, 7 of them died and 3 were taken to a rescue center. Finally, 50 managed to leave the nest successfully.
- In general, the results for this season are very positive in all stages, with rates very close to, or higher than 0.5. and a very low mortality rate.
- The first chicks hatched between the 27thand 30th These chicks hatched in early January, indicating that laying occurred in early December.
We must continue with our studies for the coming years. This first instance of data collection in which the nests and chicks were accessed has allowed us to identify weaknesses in the methodology and planning of the fieldwork; there are various opportunities for improvement for the next year and the coming seasons. However, this season has also given an idea of the reproductive state of the monitored Great Green Macaw population and has allowed the identification of some problems that affect it like the loss of these important trees and their habitat to illegal logging.
Mario Jiménez Segura
Great Green Macaw Program
Macaw Recovery Network