We report Records Appraisal Committee (RAC) decisions regarding Unusual Bird Reports received between 1 January 2015 and 31 December 2016. Among the 113 submissions accepted by the RAC were the first New Zealand records of northern fulmar (Fulmarus glacialis), Herald petrel (Pterodroma heraldica), red-footed booby (Sula sula), laughing gull (Larus atricilla) and magpie-lark (Grallina cyanoleuca), the first breeding records for Australian wood duck (Chenonetta jubata) and glossy ibis (Plegadis falcinellus), and the second accepted records of shy mollymawk (Thalassarche cauta cauta), great shearwater (Puffinus gravis) and Cape gannet (Morus capensis). Other notable records included a pair of white-winged black terns (Chlidonias leucopterus) breeding in the Mackenzie basin, and the first record of pukeko (Porphyrio melanotus) from the Snares Islands. In addition, notable influxes of brown booby (Sula leucogaster) and great frigatebird (Fregata minor) occurred during 2015-16.
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.
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 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.
Weights and body measurements from 258 male and 203 female adult (>1 year) and juvenile (
Many New Zealand forest bird species have poor flying ability, limiting their ability to recolonise vacant habitat, and restricting gene flow between populations separated by water. Three endemic passerines considered to have poor dispersal ability have been reintroduced to 3 islands in Dusky Sound where stoats (Mustela erminea) have been eradicated: South Island robins (kakaruwai, Petroica australis) to Anchor Island (1,137 ha), Indian Island (168 ha) and Pigeon Island (73 ha), mohua (yellowhead, Mohoua ochrocephala) to Anchor and Pigeon Islands, and South Island saddleback (tīeke, Philesturnus carunculatus) to Anchor Island only. Mohua have also been reintroduced to nearby Resolution Island (20,887 ha), where stoats are controlled to low density. Stoat traps set on numerous ‘stepping stone’ islands around and between these 4 islands have created a network of predator-free habitat at varying distances from the reintroduction sites. We recorded sightings of these species during landings on 56 islands in Dusky Sound in November 2016. South Island robins had the greatest dispersal ability of the 3 species, and were found on 33 additional islands up to 1.4 km from the nearest potential source population. In contrast, mohua and South Island saddlebacks had each crossed a single water gap only, of 90 m and 100 m respectively. One or more of these 3 species have been translocated to more than 40 islands and a few mainland sites around the South Island and Stewart Island. Information on their dispersal ability across water could guide decisions on whether further translocations are necessary, both in respect to whether birds are likely to colonise nearby islands or forest patches unassisted, and in order to manage gene flow within dispersed metapopulations. South Island robins have apparently displaced tomtits (Petroica macrocephala) on at least 9 small islands in Dusky Sound.