Pachycephalidae, Swainson, 1831

Andersen, Michael J., Fatdal, Lilly, Mauck III, William M. & Smith, Brian Tilston, 2017, An ornithological survey of Vanuatu on the islands of Éfaté, Malakula, Gaua, and Vanua Lava, Check List 13 (6), pp. 755-782 : 764

Pachycephalidae

Pachycephala chlorura intacta Gray, 1860 , Vanuatu [Melanesian] Whistler: Figure 3C–D

The polytypic Vanuatu Whistler ( Fig. 3C, D) was common at our Éfaté and Malakula sites and uncommon at both of our Banks Group sites. Vanuatu Whistlers are easily identifiable based on their bright yellow underparts with a white throat delinated by a black collar and head. Superficially, they are similarly patterned to Neolalage banksiana ; but the latter has extensive white in the tail, rump, and wings, whereas whistlers are uniformly dark green on the back. Female whistlers are muted versions of males with olive-brown backs, dull yellow underparts and a dingy white throat. Whistlers have characteristic loud vocalizations that make them easy to detect when singing. Birds on Éfaté and Malakula were singing vociferously, but were quiet on Gaua and Vanua Lava, making them more difficult to detect. Several lines of breeding evidence were noted on Éfaté and Malakula, including a female on Éfaté observed feeding a recently fledged young (21 November 2014), multiple male specimens with enlarged testes and seminal vesicles and females with convoluted oviducts, and singing males. Only 1 specimen showed signs of molt (Malakula). Conversely, specimens from Gaua and Vanua Lava were largely not in breeding condition and most were in body, wing, and tail molt. Stomach contents of all specimens were invariably of arthropods.

The Vanuatu Whistler has 4 subspecies ( Clements et al. 2016). All our surveys were within the distribution of P. c. intacta , whereas 3 others occur in the south ( chlorura on Erromango, cucullata on Anytiem, and littayei on the Loyalty Islands, New Caledonia). The taxonomic assignment of these 4 subspecies to Vanuatu Whistler is equivocal and may represent multiple species ( Jønsson et al. 2014). Its IUCN status is Least Concern. Further survey work should focus on the southern subspecies so that these are represented in global tissue collections.