It was previously considered conspecific with the Puerto Rican bullfinch (Melopyrrha portoricensis), from which it could be distinguished by its larger size, glossier feathers, and more extensive breast patch.

James Bond initially proposed that the species had been heavily reduced in number by the introduced vervet monkey (Chlorocebus pygerythrus).

[2] An alternate theory, proposed in 1977, was that the decline was due to natural causes, with competitive exclusion by L. noctis forcing M. grandis to be limited to the restricted habitat at higher altitudes, thus leaving it at much bigger risk of being wiped out by the hurricanes of 1899; however, this account was made before the description of Bartsch's specimen.

Evelyn and his wife, Joyce, were hiking near the Bloody River when they spotted a bird matching the description of the species, being almost entirely black with red on top of the head and on the throat below the chin.

[8] In 2021, a scientific experiment by Saint Kitts' Department of the Environment recorded a sonogram of a bird song that could potentially be that of M. grandis, which requires further investigation.