birds

The relative importance of birds and insects as pollinators of the New Zealand flora

Native birds may have been underestimated as pollinators of the New Zealand flora due to their early decline in abundance and diversity on the mainland. This paper reconsiders the relative importance of birds and insects as pollinators to eight native flowering plants, representing a range of pollination syndromes, on two offshore island refuges. Experimental manipulations were made on five of these plant species to assess the relative effectiveness of bird and insect visitors as pollinators.

An assessment of the probability of secondary poisoning of forest insectivores following an aerial 1080 possum control operation

Assays for the toxin sodium monofluoroacetate (compound 1080) were undertaken on arthropods collected from toxic baits after a brushtail possum (Trichosorus vulpecula) control operation in Nothofagus forest in central North Island, New Zealand. The 1080 concentrations measured (mean 57 mu g per g, max 130 mu g per g) are considerably higher than those reported by other researchers who collected arthropods randomly after control operations.

The risks, costs and benefits of using brodifacoum to eradicate rats from Kapiti Island, New Zealand

In 1996 an eradication operation against two species of rats (Rattus norvegicus and R. exulans was conducted on Kapiti Island (1965 ha) and its small offshore islands. Trials with non-toxic baits had been carried out to help determine the risks to non-target species, and research was undertaken to collect baseline data for measuring the response of vegetation, invertebrates, reptiles and birds to the removal of rats.

Fate of moreporks (Ninox novaeseelandiae) during a pest control operation on Mokoia Island, Lake Rotorua, North Island, New Zealand

We monitored 16 radio-tagged moreporks (Ninox novaeseelandiae) on Mokoia Island after a brodifacoum poison drop to eradicate mice (Mus musculus), normally included in the owls' diet. All 16 moreporks were alive after 13 days. One bird was found dead on day 22, and corpses of two radio-tagged birds were located on day 51. The bird found on day 22 contained 0.97 mg kg(-1) of brodifacoum in its liver. The other two carcasses were not analysed, but they probably died as a result of brodifacoum poisoning. Thus, three out of 14 birds died (21% mortality).

The toxicity of sodium monofluoroacetate (1080) to Huberia striata, a New Zealand native ant

Although many species of native invertebrates have been identified on toxic baits containing sodium monofluoroacetate (1080) following aerial operations for possum control, few quantitative data are available to determine the risk of primacy or secondary poisoning that may result from these exposures. This paper reports on a series of studies conducted to determine the risk of 1080 exposure to one such non-target insect, the native ant Huberia striata. Subsequent risk of secondary poisoning to insectivorous animals is extrapolated.

Honeyeaters and the New Zealand forest flora: The utilisation and profitability of small flowers

New Zealand flowers are frequently considered unspecialised allowing easy access to pollen and nectar by a wide range of visitors. Most conform with a syndrome of insect pollination (entomophily). Pollination of forest flowers by birds has been described for a range of species whose flowers are morphologically ornithophilous. On Kapiti Island and Little Barrier Island, all three species of New Zealand honeyeaters have been described feeding on flowers currently assumed to be entomophilous or where the pollination system is unknown.

The diet of the North Island kaka (Nestor meridionalis septentrionalis) on Kapiti Island

Food of the North Island kaka (Nestor meridionalis septentrionalis) on Kapiti Island was identified while quantifying the foraging activity of nine radio-tagged birds from March 1991 to January 1992. Additional food types were identified by opportunistic observation of feeding birds and qualitative examination of nestling faeces. A diverse range of food was taken, including wood-boring invertebrates, scale insects, seeds, nectar or pollen, fruits, and sap.

Ecology of the stoat in Nothofagus forest: Home range, habitat use and diet at different stages of the beech mast cycle

We studied the ecology of a high-density population of stoats in Fiordland, New Zealand, in the summer and autumn of 1990-91 following a Nothofagus seeding in 1990. Results are compared with findings from the same area in 1991-92, a period of lower stoat density. In the high-density year, minimum home ranges (revealed by radio-tracking) of four females averaged 69 ha and those of three males 93 ha; range lengths averaged 1.3 km and 2.5 km respectively. Neither difference was statistically significant.

Large-Scale Poisoning of Ship Rats (Rattus rattus) in Indigenous Forests of the North-Island, New Zealand

This paper describes the impact of nine poison operations on ship rats in four areas (35 ha to 3200 ha) of North Island forest. Poisoning with 1080, brodifacoum, or pindone killed 87- 100% of rats, based on trapping and tracking-tunnel indices. Rat populations took 4-5 months to recover. Operations to protect nesting birds should therefore coincide with the onset of nesting and be rePeated each year, although not necessarily with the same methods.

Feeding by Captive Rare Birds on Baits Used in Poisoning Operations for Control of Brushtail Possums

Non-toxic plain and cinnamon-flavoured carrots and cereal-based baits used in poisoning operations for control of the brushtail possum (Trichosurus vulpecula) were offered to seven species of captive rare birds at Mt Bruce National Wildlife Centre. Some individuals of all species ate plain baits.

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