The rediscovery of Monarcha boanensis (Aves: Monarchidae) from Boano Island, Indonesia

Since more than 50 years after its description, the black-chinned monarch Monarcha boanensis van Bemmel, 1939 had only been known from a single specimen (the holotype) that was collected in 1918 on the Moluccan Island of Boano (Indonesia). Four expeditions to Boano in search of this bird were made between 1990 and 1994. The species was rediscovered in 1991 in a forested limestone gorge in the foothills of the mountainous part of the island. A juvenile was collected. The same area was surveyed again in 1994, then 5-l 0 individuals were observed of which several were heard singing. An adult was captured and photographed. This paper summarizes the expeditions and provides descriptions of the birds both i.n the hand and in the field. Data on the type-specimen, voice, food, behaviour, habitat and population size are given. As for taxonomy, it is concluded that M boanensis is more closely related to the pied species-group, especially M leucurus, than to M. trlvirgatus. The rather intermediate position of the bird as to plumage and measurements supports its proposed, and already widely used, full-species status.