Pacific robin

The Pacific robin (Petroica pusilla) is a small passerine bird from Melanesia and Polynesia, belonging to the Australasian robin genus Petroica. Its plumage resembles that of Australia’s scarlet robin, and the two were treated as the same species until 1999, when Schodde and Mason separated them. Thirteen subspecies are now recognized, showing notable differences in feather color, feeding habits, and preferred environments. The Norfolk robin, once considered a subspecies of the Pacific robin, is now classified as a separate species.

German naturalist Johann Friedrich Gmelin first described the Pacific robin in 1789, based on a specimen from Norfolk Island. It was grouped with the scarlet robin until the 1999 split, and together with that species and New Zealand’s tomtit, it forms a species group. In 2015, the Norfolk robin was also split off. Because the Norfolk birds were discovered first, they kept the species name multicolor, while the Pacific group took the next available name, pusilla.

The nominate subspecies, found in Samoa, was described by American naturalist Titian Peale in 1848. The genus name Petroica comes from the Ancient Greek words petros (stone) and oikos (home), while the species name pusilla is Latin for “very small.” This bird is one of five red- or pink-breasted species in the genus often called “red robins.” Despite its name, it is not closely related to the European robin or the American robin.

For many years, it was placed in the Old World flycatcher family (Muscicapidae), then in the whistler family (Pachycephalidae), before being moved to its own family, Petroicidae. DNA studies by Sibley and Alquist initially put these robins in a large group of tropical and Australian songbirds, but later molecular research (now widely accepted) places them as an early offshoot of the Passerida, the “advanced” songbirds. The Pacific robin is small, measuring 11.5–13.5 cm in length and weighing 9–11 g. Over much of its range, it is the smallest bird species.

Description

Males and females differ in plumage, though the extent varies by subspecies. The male of the nominate race has a black head with a white forehead, black back and tail, black wings with a white bar, and a red breast and belly, with white on the lower belly and rump.