No abstract

Pest mammals are completely excluded from Maungatautari Ecological Island, New Zealand, by a 47-km Xcluder pest-proof fence; however, they are commonly sighted directly outside, along the fenceline. Permanent pest exclusion relies on maintaining fence integrity, and enhancing knowledge of pest activity and behaviour at fenced reserves. We describe summer and winter periods of activity and behaviour of mammalian pests directly adjacent to the pest-proof fence. We (1) tested for the effects of adjacent habitat type, breach type and season on the rate of mammalian pest sightings directly at the fence, (2) determined how quickly pest mammals may locate a fence breach, and how likely they are to exploit it, and (3) developed a predictive model to help assess the probability of a pest gaining entry to the sanctuary if repair to a fence breach is delayed. Observations inside the rolled fence hood provided firm evidence that rats travel and forage extensively in this artificial although highly acceptable aboveground habitat, much more than on the ground. We confirm and emphasise that mammalian pests are constantly testing the pest-proof fence. Pests are very common directly outside the fence, and within 24 h there is a very high likelihood that a fence breach will be located and exploited. The greatest threat of reinvasion comes (1) nocturnally, (2) from rodents and (3) in the summer; however, these results also confirm that there is constant risk from multiple pest species, regardless of time of day or season.

We recorded the responses of free-ranging house sparrows (Passer domesticus) to various concentrations of primary repellents and a secondary repellent. Wheat treated with either lime or neem oil was consumed by sparrows at the same rate over 24 hours as plain wheat at all doses. dpulegone significantly reduced wheat consumption from day 1 onwards throughout the 4 days. Avex TM (containing the secondary repellent anthraquinone) did not significantly reduce wheat consumption on day 1 of exposure, but sparrows ate progressively less repellent wheat over the following days. For both d-pulegone and Avex TM , there was a negative relationship between wheat consumption and repellent concentration. In experiment 2, the highest concentrations of Avex TM ' d-pulegone combined reduced daily wheat consumption significantly more than Avex TM alone and the effect lasted throughout the 10-day test. These results demonstrate the potential of primary and secondary repellents, presented alone or in combination, for modifying the feeding behaviour of sparrows.

These data demonstrate the potential of combining the secondary repellent AQ with additional salient cues for modifying the feeding behaviour of sparrows.