[4] The nominate subspecies lives in the canopy of wet tropical forests and in Costa Rica is usually associated with the almendro tree, Dipteryx oleifera.

Le Vaillant states that it is not certain if the bird is truly a distinct species of parrot, or, as he thinks more likely, it is specific varietal race of the military macaw, but nonetheless, he must mention that its existence merits notice.

[24] In Costa Rica the habitats where great green macaws occur during breeding season is dominated by the almendro (Dipteryx oleifera) and Pentaclethra macroloba, with secondarily raffia palms (Raphia spp.)

[14][21][23][25] The population in Ecuador is thought to be split into two disjunct areas in the western coast of the country, the coastal mountain range of the Cordillera de Chongon in southwestern Ecuador, and in the far north bordering Colombia from the west in Río Verde Canton in central coastal Esmeraldas Province, stretching eastwards into Imbabura Province.

[14][23][27][28] In Panama it is common in some areas such as the Caribbean slope and in parts of Darién National Park such as the famous Cana birdwatching site and across the Alto de Nique mountain and the adjacent border with Colombia.

[14] In Costa Rica in the early 2000s, the reproductive range of the great green macaw was thought to be restricted to 600 to 1120 km2 of very wet forests in the northeast along the border with Nicaragua.

After the breeding season this population disperse in larger groups to higher altitudes both southwards in the central cordillera of Costa Rica as well as northwards to Nicaragua.

[31] To improve the state of knowledge of the natural history the great green macaw in Costa Rica a large study using radio telemetry was launched by George V. N. Powell and conducted by a team of researchers from 1994 to 2000.

Birds have been recorded feeding on a wide variety of foodstuffs in the wild such as seeds, nuts and fruits, but also including flowers, bulbs, roots and bark.

[21] In Costa Rica at least 38 plants are used for food, of which the most important are the seeds or nuts of Dipteryx oleifera (almendro), Sacoglottis trichogyna, Vochysia ferruginea and Lecythis ampla.

[34] Within 50m distance from the lagoons in Maquenque National Wildlife Refuge the following plants have been recorded as food plants for the great green macaw: the palms Iriartea deltoidea, Raphia taedigera, Socratea exorrhiza and Welfia regia, the large shrub Solanum rugosum, the emergent trees Balizia elegans and Dipteryx oleifera, and the trees Byrsonima crispa, Cespedesia macrophylla, Croton schiedeanus, Dialum guianense, Guarea rhopalocarpa, Laetia procera, Maranthes panamensis, Pentaclethra macroloba, Qualea paraensis, Sacoglottis tricogyna, Vantanea barbourii, Virola koschnyi, V. sebifera and Vochysia ferruginea.

[23] After the two most important trees of the breeding season are no longer in fruit the macaws gather together in flocks and begin to migrate away from the Dipteryx forests.

Terminalia catappa, the beach almond (locally also known as almendro), is a commonly planted and naturalised tree from the old world, which these macaws have also been observed feeding on in gardens in Suerre, Costa Rica, between July and September during their migrations – they use fragments of the leaves to help scrape the flesh off the fruits in order to obtain the nuts, and depart after feeding on the trees for 40 minutes.

[39] The great green macaw's breeding season starts in December and ends in June in Costa Rica,[21][36][40] and from August to October in Ecuador.

guayaquilensis has used a hole in a dead tree of the species Cavanillesia platanifolia at least one time,[17][26] and has shown a preference for living Ceiba trichastandra in southern Ecuador.

A. canestrinii pro parte) was recovered from old museum specimens of Ara ambiguus collected in Costa Rica, Panama and Nicaragua.

This is a tiny ectoparasite or possibly commensal, likely, based on related species, inhabiting the wing feathers on the ventral surfaces of the secondaries and inner primaries in the channels formed by adjacent barbs.

It is typified by a swollen proventriculus and tiny lesions which appear in the ganglia and nerves, and the affected birds show abnormal movements and have problems feeding.

[46] A festival organised by the Centro Científico Tropical, the Fundación del Río and more recently The Ara Project promoting great green macaw conservation and bi-national relations is held each year since 2002 in alternatively Costa Rica and then Nicaragua.

Healthy birds enjoy large chewable toys and weekly decorations of fresh branches of pine or eucalyptus in their enclosure.

Important is soaked and/or sprouted seeds, as well as some fresh vegetables and fruit, along with nutritionally complete standard commercial macaw pellets.

While conservation projects have had success educating people and releasing great green macaws into the wild, their numbers remained between 500 and 1000 individuals worldwide as of 2020.

[29] Private land not owned by the government is or has been developed into agricultural fields for the production of crops such as oil palm, pineapples and bananas.

[25] Other threats have included hunting pressure for sport and the feathers, and the pet trade, with chicks fetching prices of up to $300 in Costa Rica in 2001.

[41] In Costa Rica commerce of the macaw was reduced after an environmental education program was initiated in 1998 by George Powell and his research team.

[49] In 1998 this research team, later united as Centro Científico Tropical, devised a conservation plan with an alliance of 18 different organizations known as the San Juan-La Selva Biological Corridor which would protect the habitat of the great green macaw.

[5][49] An earlier iteration of this plan had first been proposed in 1985 by the first revolutionary Sandinista government in the midst of the US-sponsored Contras insurgency, as an "international ecological peace park" (SI-A-PAZ), but the binational agreements with the Costa Rican government were never carried out, so instead Nicaragua established the vast "Áreas Naturales Protegidas del Sureste de Nicaragua" in the southeast, and a similar block of land in the northeast bordering Honduras.

[25] The new "biological corridor plan" entailed the creation of the Maquenque National Wildlife Refuge in Costa Rica in 2005, which helps connect the six previously existing protected areas of the Tortuguero National Park and La Selva Biological Station in the Cordillera Central in Costa Rica, with the Barra del Colorado Wildlife Refuge, the Indio-Maíz Biological Reserve, Punta Gorda Natural Reserve and the Cerro Silva Natural Reserve in Nicaragua, thereby allowing animals to move between the regions.

[25] A national prohibition of the cutting of almendro de montaña (Dipteryx oleifera) trees was also engineered by the Centro Científico Tropical.

guayaquilensis is mostly protected in the Cerro Blanco Forest just west of the city of Guayaquil, a private reserve administered by the Ecuadorian NGO Fundación Pro-Bosque, which is expanding the plantings of native trees on the grounds.