Diet and biology of the laughing owl Sceloglaux albifacies (Aves: Strigidae) on Takaka Hill, Nelson, New Zealand

The faunal composition of two Holocene fossil deposits of small vertebrates provided new information on the diet and biology of Sceloglaux albifacies , a strigid owl endemic to New Zealand. The taxonomic composition and several measures of diversity of the prey accumulation are given. Most taxa in the deposit had a mass of 50-150g, but species up to 400g were also present. The owl was a generalist feeder, but the prey biomass distribution showed that a few taxa provided most of its energy requirements. Changes in the diet appeared to coincide with the appearance of Rattus exulans , the Polynesian rat, and the consequent decline or extinction of several prey. The ecologies of extant taxa represented in the deposit suggest that the owl was primarily a nocturnal forest species. Many prey taxa were terrestrial. Species richness was higher for both diurnal (by 50%) and nocturnal (by 63%) vertebrates in the deposit than in the present fauna around the site. Analysis of possible guilds in the pre-human and present faunas of Takaka Hill suggests that ground-frequenting taxa were most severely affected by extinctions; three guilds vanished entirely.