The chestnut-bellied monarch (Monarcha castaneiventris) or chestnut-bellied monarch-flycatcher is a species of bird in the family Monarchidae. It is endemic to the Solomon Islands.
M. c. erythrostictus has sometimes been treated as a separate species, the Bougainville monarch
Behaviour and ecology
In 2009, it was reported that a genetic change in some members of this species caused their colouration and songs to be different from other members of the species. As a result, members in one group did not recognize members in the other, so the two groups became reproductively isolated from each other. It was thought that over time, this could eventually lead to the creation of a new species, and that this was an example of biological evolution.[3]
^Gill, Frank; Donsker, David; Rasmussen, Pamela, eds. (August 2024). "Monarchs". IOC World Bird List Version 14.2. International Ornithologists' Union. Retrieved 9 September 2024.