The Rodrigues night heron was robust, its bill was comparatively large, stout and straight, and its legs were short and strong.

Little is known about the bird's behaviour, but the contemporary accounts indicate that it ate lizards (probably the Rodrigues day gecko), was adapted to running, and although able to fly, rarely did so.

The French traveler Francois Leguat mentioned "bitterns" in his 1708 memoir A New Voyage to the East Indies about his stay on the Mascarene island of Rodrigues from 1691–93.

[4] In 1873, the French zoologist Alphonse Milne-Edwards described subfossil bird bones from Rodrigues he had received via the British ornithologist Alfred Newton.

These had been excavated in 1865 under the supervision of his brother, Colonial Secretary Edward Newton, by the police magistrate George Jenner, who found the specimens in a cave on the Plaine Corail, near Rodrigues solitaire remains.

[7] In 1875, A. Newton correlated references to "bitterns" with the heron in the then recently rediscovered 1725–26 account of the French sailor Julien Tafforet, Relation de l'Ile Rodrigue, which he thought confirmed Milne-Edwards's conclusions.

[9][3] More fossils were obtained from caves by the palaeontologist Henry H. Slater in 1874, and these were described by the German zoologist Albert Günther and E. Newton in 1879, with the benefit of bones not known at the time of Milne-Edwards's original description.

[11][12] The Japanese ornithologist Masauji Hachisuka concluded in 1937 that this species was little related to any other heron, and moved it to a new genus as Megaphoyx megacephala.

Hume stated that while there had been no molecular analysis to examine the interrelationships of the Mascarene herons, the Rodrigues and Mauritius species appear to have been closely related.

Hume added that a complete Rodrigues night heron sternum he had found in Caverne Dora in Plaine Corail near other subfossil bird bones was the only known specimen of this species photographed in the location it was found, and that radiocarbon dating of a nearby Rodrigues scops owl humerus gave a range of 3060–2870 years before present.

[3] Hume stated in 2023 that this probably means that the Mascarene herons retained their juvenile (paedomorphic) plumage into adulthood, as is the case for some other island birds.

It may have inhabited and foraged in open forests containing palms with geckos, which is also the main habitat of invertebrates that live in leaf-litter, such as terrestrial crabs, and at other times of the year it could have scavenged from coastal seabird colonies and giant tortoise breeding grounds.

He also found the legs to be proportionally short in relation to the large head, but with a well-developed femur, which he inferred to mean that the body of the bird was bulky.

On the other hand, they found the leg bones to be better developed and the body size equal to the extant night heron, since they could compare the pelvis, which had been unknown to Milne-Edwards.

They found the foot-bones to be very well-developed, thicker than in the black-crowned night heron, and considered this a sign that the bird was much more cursorial (adapted to running), and would have chased swift, terrestrial animals (such as lizards) rather than aquatic prey.

They concluded that the bird had become short-winged without losing the power of flight but it compensated for this by the increased development of the legs, especially by enlarging the metatarsus so it could receive and serve as a base for the foot's tendons.

[10][17] Hachisuka disregarded Tafforet's account in 1937, believing it unlikely that the bird would have been able to rise from the ground because its sternum and wing remains indicated it had become flightless (while he quoted but ignored Günther and Newton's statement that it had not lost the power of flight).

[13][16] The American ornithologists Storrs L. Olson and Alexander Wetmore pointed out in 1976 that the fossils of this heron did not indicate it was entirely flightless, contrary to Hachisuka's claim, as its sternal carina (or keel) was still rather well-developed, and the wing-elements not very reduced.

This gave them the impression that the wings of the Rodrigues night heron were unusually small; Cowles noted they are not when compared to the European subspecies.

[5] Hume and the British ornithologist Michael Walters stated in 2012 that the extinction was a consequence of severe deforestation and introduced predators, such as cats.

[25] Cheke responded in 2013 that there was no deforestation at the time, the species appeared to have survived introduced rats, and that cats were the main culprits.

Tortoise hunting was no longer viable by the 1770s, and although the hunters probably also killed the birds, it was probably the introduction of cats in 1750 that led to their extinction, most likely by Pingré's 1761 visit a decade later.