Ecology of an uncommon species, the black-chinned honeyeater ('Melithreptus gularis gularis'), in north-eastern New South Wales

Abstract

This study investigated why the black-chinned honeyeater ('Melithreptus gularis gularis') is uncommon in the Bundarra-Barraba region of New South Wales and tried to establish if the species is declining. The study took place from 2003 to 2006 and encompassed examinations of foraging, movement, habitat selection, recruitment, and detection rate of the species. General foraging behaviour of the black-chinned honeyeater was studied and compared with a common co-occurring relative, the fuscous honeyeater ('Lichenostomus fuscus'). Although, both species foraged in similar ways, small differences in foraging behaviour were evident. The fuscous honeyeater had a more diverse range of foraging manoeuvres and black-chinned honeyeaters spent a larger proportion of foraging in larger trees than the fuscous honeyeater. When a closer look at canopy foraging was taken, black-chinned honeyeaters fed much more often on invertebrates that bound leaves together than did fuscous honeyeaters, which foraged more often by gleaning off the surface of leaves. The foraging movements of three black-chinned honeyeaters and three fuscous honeyeaters were examined by radio-tracking. Although sample size was small, limiting the generality of the results, black-chinned honeyeater home ranges were much larger than those of fuscous honeyeaters. Flights between foraging trees were also longer for the black-chinned honeyeater than for the fuscous honeyeater. The difference in home range and flight distances may be because the black-chinned honeyeater consumes prey that is more sparsely distributed than the fuscous honeyeater's prey. ... The black-chinned honeyeater is likely to be a naturally uncommon species because its food supply is sparsely distributed across the landscape. It is likely to be a declining species and future degradation to its preferred habitat may exacerbate its rarity. More research into foraging and food distribution is needed. Population monitoring using appropriate ecological methods also needs to be established.