The great green macaw (Ara ambiguous) is a large, green parrot known for its loud and consistent calls. These macaws typically live in humid and wet Neotropical lowlands and foothills, but can be found on edge habitats and will cross large open areas. They have a strong preference for Dipteryx panamensis (common name: almendro, mountain almendro), but will also feed from Terminalia catappa (common name: beach almond). These macaws are very social, with family groups of 5-6 individuals and foraging and roosting groups of up to 50. 

With an estimated 500-1,000 individuals left in the wild, a number believed to be decreasing, great green macaws are classified as critically endangered by the IUCN Red List of Threatened Species. Their biggest threats are the destruction of habitat for human development, particularly logging for agriculture, and removal from the wild for the pet trade.

Great green macaws have been observed in the CPBS area since 2013, when previously sporadic events began to become a common occurrence, providing evidence of the formation of a local population. It is thought that local almendro trees could be a driving factor in the recent influx of these birds to the area. 

CPBS began officially surveying the great green macaw in 2017 with the purpose of determining the local abundance in Tortuguero to monitor the population over time, and to identify local movement patterns. Surveys take place once weekly (one morning and one evening for each survey day) at one of five locations along the Caño Palma, in San Francisco, and Tortuguero. When detected, surveyors record the location of the macaw(s), the number of individuals, their behaviour, and the direction in which they travel from/to. If scarlet macaw (Ara macao) are present, the same information is recorded as an incidental occurrence.