Singing Activity of the Bonin Islands Honeyeater Apalopteron familiare (Passeriformes, Meliphagidae)

Abstract

The Bonin Islands Honeyeater Apalopteron familiare is a passerine species endemic to the Ogasawara (Bonin) Islands, 1, 000km south of the Japanese mainland. The male Bonin Islands Honeyeater has been thought to sing rarely, even in the breeding season. To determine whether or not males were poor singers, I examined the diurnal rhythm of singing activity and the distribution of singing males in Hahajima in early June 1991.
Two supposedly paired males showed a remarkable diurnal rhythm of singing activity. They sang actively between 0400h and 0430h in the morning, but then virtually ceased to sing, singing only sporadically in the daytime. Between 91 and 94 songs were delivered between 0400h and 0430h, accounting for 93.8% (91/97) and 71.2% (94/132) of the total songs in one day. Singing males were well recorded in the Okimura village between 0400h and 0500h, but rarely recorded between 0500h and 0700h in the mornings of June 3 to 8. Singing males were infrequently recorded in the daytime, even though they were widely distributed on Hahajima.