Although fecal pellet counts have been widely used to index changes in deer abundance in forests, few studies have modeled the relationship between the indices and deer density. We examined the relationships between 3 fecal pellet indices (total pellets, pellet groups, and pellet frequency) and the density of deer (primarily red deer [Cervus elaphus scoticus]) in 20 enclosures in the North and South islands of New Zealand. In each enclosure we estimated the 3 indices on 30 randomly located 150-m transects, with each transect having 30 circular plots of 3.14 m 2 . We developed 4 candidate models (1 linear and 3 nonlinear) to describe the relationship between the indices and deer density. We used a Bayesian analysis to account for uncertainty in the estimates of deer abundance and to facilitate fitting models that included random transect effects. The 4 models explained the relationship between the 3 indices and deer density similarly well. The slopes of the linear relationships between the 3 indices and deer density were positive. Our results suggest that fecal pellet counts may be useful indices of deer abundance. (JOURNAL OF WILDLIFE MANAGEMENT 71 (3):964-970; 2007)

The probable cause of possums (Trichosurus vulpecula) becoming 'shy' towards 1080 [sodium fluoroacetate] bait, a growing problem in the control of this pest, was determined. Possums captured from North Canterbury, New Zealand, (n = 131) were offered sublethal baits (1 or 2.5 g) followed by lethal (6 g) baits 2 days later. Most possums became bait shy and the proportion becoming shy appeared to be related to the size of the initial sublethal dose. Most of a group of survivors retested after 3 months with toxic pellets were still shy. Shyness was not overcome by changing to a different mask (orange flavour, as opposed to cinnamon flavour) or toxin (brodifacoum), but changing to both a different bait base (carrot) and mask (orange) resulted in most shy possums eating a lethal quantity of bait. Possums therefore appeared to learn to recognise the bait base as the cue for avoiding poisoning. More shy possums than naive possums rejected non-dyed, non-masked, non-toxic pellets, confirming that shy possums recognised the bait base. Green dye appears to act as a secondary cue for avoiding pellets as a higher percentage of 'shy' possums than naive possums rejected dyed baits.

New Zealand aims to eradicate possums (Trichosurus vulpecula) and ship rats (Rattus rattus) nationally by 2050. This aim will require more effective tactics for locally eliminating these pests. Therefore, we explored whether possums and rats could be eliminated from large areas using pre-feeding and two applications of sodium fluoroacetate (1080) bait spaced a few months apart. The specific key question we investigated was whether any bait aversion learned by possums or rats that survived the first application of 1080 cereal bait would be overcome by a second application. A two-stage field trial was undertaken in 2016 and 2017, using 100-ha forested study blocks near New Creek, Westland. In the first stage, eight blocks were aerially baited with 1080 after being aerially pre-fed twice, once, or not at all. The relative abundance of rats fell to zero immediately after the baiting in all four blocks that were pre-fed, but lesser reductions in the four blocks not pre-fed. The survivors in the non-pre-fed blocks appeared to be universally and strongly bait averse. In the second stage, the non-pre-fed blocks were then aerially pre-fed twice and 1080-baited (by hand laying) with a bait type that differed slightly in appearance and smell from the original. Based on trail camera visitation rates and chew card interference, the relative abundance of rats fell to zero or close to it in the second group of four blocks, whereas possum activity indices increased markedly after an initial one week dip. The increase in possum activity was attributed to the peanut bait used in the chew cards attracting possums to monitoring sites. We conclude that dual application of 1080 using a similar bait in a single operation has the potential to locally eliminate rats from large areas, and that with further development involving use of two very different bait types and/or different pre-feeding sequencing, could potentially achieve the same for possums.

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