As this species - the second-largest coua extant in modern times - was very spectacular, it was much sought after as a museum piece.

However, it probably was restricted to coastal rainforest on Nosy Boraha, and its habitat was largely destroyed by deforestation in the course of the 19th century.

There are some reports that the locals on the adjacent mainland were still occasionally hunting this bird for its decorative plumage in the 1920s, but these seem in error, these records probably referring to the blue coua.

What is known with certainty is that in 1932, large sums were offered to well-connected animal dealers in Antananarivo for specimens of Delalande's coua, but they were unable to procure any.

The color pattern of the species is unique among couas, which may be a hint that it evolved in fact in the isolation of Nosy Boraha and never occurred anywhere else.