To effectively monitor bird populations, accurate identification of species is critical. However, the reliability of species identification is rarely taken into account or quantified. For this study, bird call data was collected using automated acoustic recording devices (ARDs) over a 3-year period. We then compared the results from experienced ornithologists who independently identified bird calls from the same samples. Results were highly variable.
Declines in native birds in New Zealand have raised questions about whether seed dispersal limits plant regeneration and whether introduced mammals such as brushtail possums (Trichosurus vulpecula) can replace absent native birds. We determined the relative contribution to seed dispersal by birds and possums in native secondary forest at Kowhai Bush, Kaikoura. The number of seeds dispersed per hectare per day by each animal species was determined based on the number of seeds per faecal pellet, the number of faecal pellets per animal per day, and the density of animals per hectare.
There are currently many attempts in New Zealand to restore native ecosystem functioning through the intensive control of introduced mammalian predators. One system that is faltering is bird pollination of endemic mistletoes (Peraxilla tetrapetala) by bellbirds (Anthornis melanura), apparently because of stoat (Mustela erminea) predation. We used a paired-catchment experiment in Nothofagus solandri var. cliffortioides forest at Craigieburn, central South Island, to measure whether stoat control could restore bellbird densities and mistletoe pollination.
To examine the seasonal availability of the major bellbird (Anthornis melanura) food sources in a mountain beech (Nothofagus solandrivar. cliffortioides) forest at Craigieburn, the invertebrate, honeydew, and mistletoe (Peraxilla tetrapetala and Alepis flavida) fruit and nectar resources were sampled over 12 months. The total available food varied 2.6-fold from a low in October (8798 kJ/ha) to a high in December (22,959 kJ/ha) with an annual mean of 15,782 kJ/ha.
Recent work at several central South Island sites has shown that the bird-pollinated mistletoe Peraxilla tetrapetala (Loranthaceae) is extensively pollen-limited. We studied the diet, time-budget, and densities of its principal pollinator, bellbirds (Anthornis melanura, Meliphagidae), at Craigieburn to find out what aspect of bellbird ecology may be limiting pollination.
Honeydew is produced by a scale insect (Ultracoelostoma assimile, Margarodidae) in some Nothofagus forests of South Island, New Zealand. The quantity of honeydew present and its sugar concentration varies through the year. Honeydew is a valuable resource for bellbirds (Anthornis melanura), tuis (Prosthemadera novaesealandiae) and silvereyes (Zosterops lateralis). Bellbirds and tuis were commoner in forests with more honeydew. Bell- birds spent more time feeding on honeydew when its sugar concentration was low.
To make sense of how nature is responding to an increasingly rapidly changing world, a lot of species distribution and abundance data are needed. To infer population trends, these data ideally need to be collected in a standardised, repeatable manner that includes ‘absence’ data on species sought for but not found. If many people, even just professional ecologists and postgraduate students, are to record biodiversity frequently in their daily lives, a convenient method that meets these requirements is needed.
Urbanisation is a significant and increasing threat to biodiversity at the global scale. To maintain and restore urban biodiversity, local communities and organisations need information about how to modify green spaces to enhance species populations. ‘Citizen science’ initiatives monitoring the success of restoration activities also require simple and robust tools to collect meaningful data. Using an urban monitoring study of the bellbird (Anthornis melanura), we offer advice and guidance on best practice for such monitoring schemes.
The suitability of line-transect-based distance sampling to robustly estimate population densities of bellbird (Anthornis melanura), kererū (Hemiphaga novaeseelandiae), North island tomtit (Petroica macrocephala toitoi) and tūī (Prosthemadera novaeseelandiae) during concurrent multi-species surveys was investigated. Densities were estimated annually from 2006 to 2009 at three sites within the Coromandel Forest Park, New Zealand.