This species was found on Réunion Island, but became Extinct sometime in the early to mid 1700s. Hunting and introduced predators are likely to have driven its decline.

Threskiornis solitarius is known from subfossil remains discovered on Réunion (to France) (Mourer-Chauviré and Moutou 1987).

No extant population remains.

It is likely to have inhabited freshwater wetlands, but was reportedly a montane species that inhabited the tops on mountains, but this may have been due to range contraction from an expanding human population (Hume 2017).

The species range reportedly swiftly contracted as Réunion became more populated (Hume 2017), so habitat loss was likely a threat. However, the bird was easily hunted, and over-hunting along with impacts from introduced predators (presumably cats and rats) were likely the main drivers of declines (Hume 2017).

Over-hunting likely was a primary driver of the species' extinction (Hume 2017).