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Figure 11. Nesting success in relation to nest site topography for individual years. X-axes = slope (degrees from horizontal), Y-axes = altitude (metres above sea level). ▲ = failed sites, ❍ = successful sites. 1400 1200 1000 800 1997 600 20 30 40 50 60 1400 1200 1000 800 1994 600 20 30 40 50 60 1400 1200 1000 800 1993 600 20 30 40 50 60 1400 1200 1000 800 1998 600 20 30 40 50 60 1400 1200 1000 800 1995 600 20 30 40 50 60 21
Predation of adult females in their nests The females from 5 of the 11 nests whose contents disappeared had been marked with leg bands prior to the disappearance of the eggs or chicks. All of these were confirmed to be alive after the nest contents disappeared. At the other six nests where the nest contents disappeared, no adult females were found dead in the nests. Discussion Overall nesting success Our estimate of 51% of kea nests fledging at least one chick is similar to 54% for yellow- crowned kakariki (Elliott et al. 1996a) and 55% for mohua (Elliott 1996a) in population ‘strongholds’ in Fiordland. In contrast, kaka nesting success (in tree cavities) near our study site between 1985 and 1996 was only 10% and at least 30% of these kaka nest failures were attributed to stoats (n= 20 nests, Wilson et al. 1998). Being on the ground, then, does not seem to predispose kea nests to predation. Steep, higher altitude sites might be over-represented in our sample because they were more likely to survive to the dates on which we searched for nests (Green 1977). Such a bias would result in an over-estimate of nesting success. Overestimation can only be slight, however, as 75% of nests were found during incubation (Fig. 2). Moreover, Johnson (1979) shows that the Mayfield estimator is fairly robust to this kind of heterogeneity among nests. Predation of kea nests Even if all of the nest failures we observed were caused by predators, the predation is too low to justify immediate predator control to enhance nesting success among kea. This is especially so given that adult females seemed to escaped most nest failures. Jackson (1963) observed 17 kea nests with chicks in Arthur’s Pass and did not write of finding chicks or nesting females missing or preyed upon. Unfortunately he did not present an estimate of nesting success that can be compared with ours, but he gave the overall impression that nest predation was uncommon during his study. Nowhere in his 1963 22
Page 1 and 2: WWF-NZ Final Report Conservation ec
Page 3 and 4: There are two possible explanations
Page 5 and 6: Study site and methods • The stud
Page 7 and 8: • The radio-tagged one-year-olds
Page 9 and 10: in the hinterlands. Adult female su
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Page 13 and 14: Timing of the breeding season .....
Page 15 and 16: Chapter 2 List of tables Table 1. S
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Page 19 and 20: Bond, A. D., Wilson, K.-J., Diamond
Page 21 and 22: Kea are one of seven species of ind
Page 23 and 24: If predation and competition are th
Page 25 and 26: Locating and monitoring nests We fo
Page 27 and 28: Among-year comparisons in daily nes
Page 29 and 30: Nest density The density of kea nes
Page 31 and 32: Beech seedfall and stoat abundance
Page 33 and 34: Nest site topography Nest sites wer
Page 35: Table 2. Model-fitting summary for
Page 39 and 40: independent and stoat numbers becom
Page 41 and 42: could help to explain the differenc
Page 43 and 44: Lebreton, J.-D., Burnham, K. P., Cl
Page 45 and 46: 3. Kea (Nestor notabilis) populatio
Page 47 and 48: technology now enable detailed stud
Page 49 and 50: Parameter estimates Productivity We
Page 51 and 52: transmitter was buried under two-me
Page 53 and 54: Nest survival We previously estimat
Page 55 and 56: Pre-adult survival Of the radio-tag
Page 57 and 58: Kea population dynamics We chose no
Page 59 and 60: could result in a downgrading of th
Page 61 and 62: O'Donnell, C. F. J. 1996. Predators
Page 63 and 64: the Nelson Lakes study site. Most o

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