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Buffering artificial nest boxes for Procellariiformes breeding in exposed habitats: investigating effects on temperature and humidity

Notornis, 65 (1), 35-41

J.H. Fischer; J. Chambon; I. Debski; J.A. Hiscock; R. Cole; G.A. Taylor; H.U. Wittmer (2018)

Article Type: Paper

The tendency of various species, including many Procellariiformes, to breed in sub-terrestrial burrows, complicates breeding biology studies. Artificial nest boxes facilitate detailed data collection, but may alter the buffering capacity of natural burrows, especially when these nests are exposed to direct sunlight (e.g., in non-forested habitats). We tested the buffering capacity of artificial nest boxes, equipped with additional insulating features, ex-situ in a non-forested sand dune in New Zealand. Specifically, we compared daily temperature (°C) and relative humidity (%) means, minima, and maxima between artificial nest boxes, Procellariiform burrow replicas, and ambient conditions sourced further inland using linear mixed effects models (LMMs), followed by post-hoc tests. Differences between artificial nest boxes and replicas were non-significant (P > 0.05). Our results thus showed that the applied insulating features were sufficient to retain the buffering capacities expected in natural burrows, even in exposed habitats such as sand dunes. Hence, we encourage the use of insulated artificial nest boxes in breeding biology studies targeting burrowing Procellariiformes (and other sub-terrestrially breeding species) in non-forested areas.

Bill trait variation in kākāpō, Strigops habroptilus (Gray): differences between contemporary and historical birds

Notornis, 64 (1), 1-12

L.J. Gray; A. Digby; D.K. Eason (2017)

Article Type: Paper

Museum study-skins are an important though under-utilised resource for studying the biology of endangered birds. This study compares the bill and cere morphology of female and male kākāpō (Strigops habroptilus) from three provenances: 1) “historical wild-origin” museum specimens collected from the North and South islands of New Zealand over 100 years ago; 2) the “modern wild-origin”, predominantly ex-Stewart Island Kākāpō Recovery Programme (KRP) founder population; and 3) the “modern non-wild” descendants of the founder population raised and maintained under the conservation management of the KRP. Bill length and gape was found to be smaller in the historical wild-origin birds than in the two contemporary groups. In comparison, historical wild-origin male kākāpō had larger ceres than both contemporary groups. As bird bills can show rapid morphological adjustment to diet over generational time scales, we evaluate whether bill size differences measured could be due to differences in the nutritional environments experienced by the birds either across their life-times or over recent evolutionary time. We also discuss whether regional variation in sexual selection might account for the provenance related variation in cere size.

The changing relative abundance of grey duck (Anas superciliosa) and mallard (A. platyrhynchos) in New Zealand

Notornis, 64 (4), 211-228

M. Williams (2017)

Article Type: Paper

Change in the relative abundance of grey duck (Anas superciliosa) and mallard (A. platyrhynchos) in New Zealand, from 1950 to the present day, is summarised from trapping records, hunters’ kills, and field studies. Mallards achieved numerical ascendency over grey duck throughout most of New Zealand by the late 1970s, merely 20 years after the cessation of mallard releases by historic acclimatisation societies. Post-1990, the relative abundance of mallard in almost all districts, as recorded from hunters’ kills, appears to have stabilised at 90%, or higher. Uncertainty about hunters’ and the public’s ability to discriminate between grey ducks, their hybrids with mallard, and variably-plumaged mallard females is demonstrated and most modern (post-1990) records of relative species abundance must be regarded as quantitatively suspect. Ducks identified as grey ducks by hunters are now a relative rarity throughout New Zealand, except in Northland and West Coast. Post-1990 duck trapping in North Island indicates that grey ducks, where reported, are patchily rather than generally distributed. The absence of genetically-validated criteria for discriminating ducks of grey duck x mallard hybrid ancestry continues to confound field identifications of both species.

A survey of Fiordland crested penguins / tawaki (Eudyptes pachyrhynchus) from Cascade River to Martins Bay, South Westland, New Zealand, 2014

Notornis, 64 (4), 206-210

R. Long (2017)

Article Type: Paper

A survey of Fiordland crested penguin/tawaki, Eudyptes pachyrhynchus, breeding colonies between Cascade River and Martins Bay, South Westland, was undertaken from August to September 2014 to obtain an accurate population estimate for the area. A total of 835 nests was found, making this one of the major breeding locations for the species. This total represents a minimum estimate as tawaki nests are spread through large areas of dense forest and are very difficult to locate, and so count accurately. A total of 150 nests was observed in previous surveys of the same location. This dramatic difference in results (835 vs. 150) is attributed to a difference in survey methods and the surveyor’s familiarity with the breeding area, not a population increase. Given these results and the difficulty involved in locating tawaki, it is likely that the species’ overall population size has been significantly underestimated.
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