The Dodo's Closest Relative: The Rodrigues Solitaire

The Rodrigues Solitaire (Pezophaps solitaria) was an extinct member of the pigeon and dove family (Columbidae). It once inhabited Rodrigues Island, located not far east of Mauritius, the home of the famous Dodo. Among known species, it is the closest relative of the Dodo. Adults reached roughly 90 centimeters in height, making them comparable in size to a swan. Their plumage consisted mainly of grey and brown tones, and the base of the beak bore a ring of black frontal ornamentation (not a cere). The species fed primarily on fruits.

Males and females differed noticeably in appearance. Males were larger and possessed darker plumage. Historical accounts indicate that individuals usually lived alone, though small groups were occasionally observed. The species was strongly territorial and would readily fight to defend its territory. During such conflicts, they used the bony knob located on their wings as a weapon.

Rodrigues Solitaire life reconstruction（圖片來源：Young MT et al. (2024)，採用 CC BY 4.0 授權）

Skeletons of the Rodrigues Solitaire, female left, male right（圖片來源：Young MT et al. (2024)，採用 CC BY 4.0 授權）

In a memoir published in 1708, the French explorer François Leguat described the breeding behavior of the Rodrigues Solitaire as follows:

"When these birds build their nests, they choose a clean place and gather palm leaves, piling them into a structure about one and a half feet high, upon which they settle. They never lay more than a single egg, and this egg is larger than that of a goose. The male and female take turns incubating it, and the chick does not hatch until about seven weeks later. During this period of incubation and the subsequent care of the young, the chick requires several months before it can feed itself. The birds do not allow any other individuals of their kind to approach within two hundred yards of the nesting area.

The most curious behavior is that the male never drives away other females that approach the nest. When he notices a female approaching, he beats his wings to produce a sound that summons his mate. The female then chases away the unwelcome visitor until it has completely left their territory. When a female encounters another male approaching, she leaves the task of expelling the intruder to her mate, and the male drives the rival away. We observed this many times and can confirm that it is true."

Rodrigues Solitaire illustrated by François Leguat（圖片來源：François Leguat，CC0 1.0 公共領域）

The Rodrigues Solitaire survived roughly a century longer than the Dodo, becoming extinct around 1790. Some researchers suspect that the introduction of cats to the island played a role in its disappearance, while others attribute its extinction primarily to human hunting. Rodrigues Island covers only about 108 square kilometers, and since the nineteenth century there have been no records of large birds like the Rodrigues Solitaire being observed there.

In August 2024, Mark Young published a paper in the Zoological Journal of the Linnean Society proposing that the Dodo and the Rodrigues Solitaire belong to the same newly established subtribe, Raphina:

            └── Columbidae

                  └── †Raphini

                        └── †Raphina

                              ├── †Raphus cucullatus 

                              └── †Pezophaps solitaria

Author: Shui-Ye You

Reference:

Young MT et al. (2024). The systematics and nomenclature of the Dodo and the Solitaire (Aves: Columbidae), and an overview of columbid family-group nomina. Zoological Journal of the Linnean Society.