Forty computer-simulated populations were analysed to derive formulae for estimating density of populations from a set of distances from sample points to the nearest member, from that member to its neighbour and from that neighbour to its nearest neighbour. Distances may be truncated or unlimited.
Population models are useful tools to guide management as they allow us to project growth and persistence of wildlife populations under different scenarios. Nevertheless, good data are needed to produce reliable models, and this requirement is problematic in some situations. North Island saddlebacks (Philesturnus rufusater) were reintroduced to Boundary Stream Mainland Island in September 2004, and this was the first time this species had occurred in an unfenced mainland area since their extirpation in the 19th century.
In 1995 and 1996, release of 51 hihi (stitchbird, Notiomystis cincta) onto Tiritiri Matangi Island (wild caught on Hauturu, Little Barrier Island) marked the start of a research and ecological restoration success story. Although establishment of populations of hihi elsewhere in New Zealand has proven to be difficult, the population on Tiritiri Matangi Island has grown to c. 150 individuals and has become one of New Zealand’s few detailed case-study species.
One of the quandaries faced by ecological researchers is whether they should continue to invest in ongoing projects or whether they should shift their attention to new species or systems that may have received less attention. While research on Tiritiri Matangi has touched on a wide range of species and topics, the long-term projects on the reintroduced robin population (20 years) and hihi population (17 years) have accounted for the bulk of the published research, with 57 papers featuring these populations published to the end of 2009.