These birds are highly social.  They are usually found in pairs or small mixed-species flocks. They communicate with a range of sounds from squawks to extremely loud contact and alarm calls.

The Scarlet Macaw is frequently confused with the Green-winged Macaw, which has more distinct red lines in the face and no yellow in the wing.

Scarlet Macaws eat parts of plants, including fruit, nectar, flowers, and nuts that they are able to crack open with their strong beak. They are important seed dispersers in their native environment, carrying fruit seeds across the forest in their droppings. They gather at clay licks to eat clay, which is theorized to help them neutralize some poisons from their food.

They form strong pair bonds with their mate, showing year-round bonding behaviours like preening and regurgitating. Once a pair has formed, every one to two nesting seasons they select a suitable tree cavity for their nest. The female lays 2 to 3 white eggs and incubates them for about 35 days. The chicks are able to leave the nest at around 90 days old, but will continue to stay with their parents for about a year as they learn survival behaviours.

The Scarlet Macaw is considered Least Concern on the IUCN Red List because it has an extremely large range.  But the species is still protected under international treaties because of the risk of swift decline due to habitat loss and capture for the pet trade.

This species can live up to 100 years.