Kosrae Fruit-Dove Ptilinopus hernsheimi Scientific name definitions

22–24 cm. Sexes alike. Resembles formerly conspecific and allopatric P. ponapensis (see Taxonomy) but is smaller (wing 117·5–128 mm, versus 129–138 mm in P. ponapensis and 131–139 mm in P. porphyraceus), plumage is less yellow, has paler yellow throat, greyer (less green) hindneck, greyer (less greenish) breast, belly patch indistinct or absent and tail tipped even more broadly and brightly yellow. Proposed race marshallianus known from a single specimen originally preserved in spirit, described on basis of its orange (rather than yellow) vent and undertail-coverts, and less strongly emarginated tip to first primary.

Belongs to the large species-group centred on P. purpuratus (which see); within this, forms part of the subgroup centred on P. porphyraceus. Formerly considered a race of P. ponapensis, but in recent years both commonly lumped into a polytypic P. porphyraceus. Differs from P. ponapensis on account of its green vs broad brown-tinged black blurry belly patch (3); yellow vs whitish-yellow tail-tip (1); greyer, less yellow-shot breast, mantle and hind-crown (1); smaller size (including shorter bill) (effect size for bill –3.54, score 2). Proposed race †marshallianus (Ebon, in Marshall Is) considered a synonym of hernsheimi. Monotypic.

Apparently undescribed, but territorial song (based on single recording  ) is a series of coos, some of them double notes, that starts slowly and then speeds up slightly, remaining at same pitch and volume throughout the rest of the series, which lasts c. 7 seconds. No known differences from P. porphyraceus, but comprehensive vocal study of the four species comprising this group (see Taxonomy) is lacking.

Not globally threatened (Least Concern). Population size has not been quantified, but is suspected to be stable in the absence of evidence for any declines or substantial threats. However, the species has become extinct on Ebon, in the Marshall Is (where known solely from the type specimen), and the current range is estimated at just 110 km².