Publications Archive

The Marlborough Sounds has a coastline of 1500 km and hosts the greatest diversity of marine shag species in New Zealand. A survey of all breeding shag species was conducted in spring 2006. Apart from New Zealand king shag, 3 species were counted: spotted shag (Strictocarbo punctatus), pied shag (Phalacrocorax varius) and little shag (Phalacrocorax melanoleucos). Two other species (black shag Phalacrocorax carbo and little black shag Phalacrocorax sulcirostris) also occur in the area but were not recorded breeding. A total of 1,254 pairs of spotted shag were recorded at 193 sites, with most colonies occurring in the outer Sounds and inner Queen Charlotte Sound. Average colony size was 6.5 pairs (range 1-76 pairs), with 85% of colonies containing ≤10 pairs. The distribution of spotted shag colonies appears to be influenced by the availability of suitable cliff habitat. Breeding pied shags were found at 48 colonies, with a total of 438 pairs. Colonies were widely distributed, and average colony size was 9.1 pairs (range 1-28), with 83% containing ≤15 pairs. A total of 226 little shag pairs were found at 24 colonies, with most colonies also including nesting pied shags. Colony size was on average 9.4 pairs (range 4-24), with 75% of colonies containing ≤10 pairs. Colonies of pied shags and little shags were found mostly in native vegetation. Colonial seabirds that occur at relatively few locations can be used as indicators to establish critical thresholds for marine management and marine conservation. It is proposed that this survey provide a good baseline for such an approach in the Marlborough Sounds.

Diagnostic prey remains of Auckland Island shags (Leucocarbo colensoi) were analysed from 23 regurgitated pellets collected in August 2010 at Enderby Island, Auckland Islands. Allometric equations from a reference collection were applied to prey remains to provide estimates of prey length and wet mass. A minimum total of 1058 prey items from 7 genera were represented in pellets, with an estimated total wet mass of 13.2 kg. The mean number of prey items per pellet was 46 (range 7-90), with mean total prey mass per pellet of 589 g (range 86–1037 g). Small octopus (Octopus sp.) was by far the most important prey item and was present in all regurgitated pellets. It accounted for 57% of prey by number and 68% of prey by wet mass. Only 2 other genera contributed ≥ 5% towards the total mass of prey—red cod (Pseudophycis bachus) and triplefin (Forsterygion sp.) The overwhelming importance of octopus in the diet is unprecedented among shags for which diet composition is known.

We investigate the phylogenetic affinites of the New Zealand blue duck (Hymenolaimus malacorhynchos), a riverine specialist of uncertain relationships, using 2613 bp of DNA sequence data from 3 mitochondrial genes. Hymenolaimus has variously been considered an aberrant Anas species, or an ancient taxa in the tribe Anatini. Presently, it is placed in a highly-derived clade (Tribe Merganettini) with the shelducks. Our findings show that Hymenolaimus forms a monophyletic clade, and does not fit within any of the other duck tribes around the world. Our study also confirms convergent evolution among duck species that inhabit fast flowing rivers.

Ruru or moreporks (Ninox novaeseelandiae) are an iconic native species that are relatively widespread in New Zealand, yet little is known about populations that reside within urban areas. Here we present results from a ruru survey conducted by volunteers within the city of Hamilton, New Zealand to: 1) collect baseline data for future comparative ruru surveys, and 2) to introduce and promote ornithology to a wider audience. In addition, these data may be used to quantify the success of urban restoration projects and pest control operations, as many of the desired outcomes of those projects (e.g., increased native vegetation and reduced mammalian predators) would have a positive impact on ruru numbers. Twenty sites were surveyed in areas such as amenity parks and gullys with established vegetation. Teams of observers recorded the time and approximate bearing of all ruru vocalisations at sites for 1 h each night for 5 consecutive nights between 2000-2230 hours in late October 2011. Ruru were detected at 80% (16/20) of sites at least once over the survey period; at 13 of these sites ruru were detected on >2 nights, while birds were detected every night at 5 sites. Multiple birds were detected at 11 sites, which suggested that some may have been resident pairs and breeding. We recommend that including members of the public in similar surveys is highly desirable as it raises awareness around conservation issues and introduces ornithology to a wider audience.

We report a polymorphic population of collared petrels (Pterodroma brevipes) apparently breeding on Vanua Lava, northern Vanuatu, in the austral autumn-winter. This is one of only 5 known extant colonies of the species. One of the 2 birds captured by us matched the description of the recently described dark plumaged Pt. b. magnificens which had never been reported caught ashore previously. However, the other bird caught was a paler individual indicating that the taxon is variable in plumage colour, like other Pt. brevipes populations. We suggest that the 2 other criteria used to define the subspecies Pt. b. magnificens (body size and breeding chronology) are also questionable and require further investigation.

We report on the discovery, care, release, and post-release monitoring of the 2nd vagrant emperor penguin (Aptenodytes forsteri) recorded from New Zealand. An immature male emperor penguin came ashore at Peka Peka Beach (40° 50’ S) 56 km north-east of Wellington on 20 Jun 2011. Its condition deteriorated over the following 4 days, and it was taken into care at Wellington Zoo on 24 Jun. Following 72 days of rehabilitation, the bird was released at sea at 51° 42’ S, 78 km north of subantarctic Campbell I, on 4 Sep 2011. He was tracked, via satellite transmitter, moving south-east for 113 km until 9 Sep, after which no further signals were received. The arrival, care and release of this penguin attracted unprecedented levels of public and media interest for a vagrant bird to New Zealand.

Deliberate taxon substitution is a much discussed but rarely enactioned concept in restoration ecology. We describe the successful establishment of a translocated population of Snares Island snipe (Coenocorypha huegeli) on Putauhinu I, which lies alongside Taukihepa (Big South Cape I), the last stronghold of the extinct South Island snipe (C. iredalei). Thirty Snares Island snipe were captured on North East I, Snares Is in Apr 2005 and released 3-5 days later on Putauhinu I. A survey on Putauhinu I in Mar 2011 resulted in the capture of 54 descendants of the released birds and a population estimate of at least 320 birds. This is one of few documented translocations of an organism with the specific objective of replacing a closely related extinct taxon. As a result, the Snares Island snipe is probably more abundant than at any time in its evolutionary history.

To date there has been no published information describing the relative abundance, behaviour or distribution of the New Zealand king shag (Leucocarbo carunculatus) within mussel farm areas, despite the sensitivity of the species to human disturbance and the potential overlap of its range with proposed development of marine aquaculture. Four survey methods were employed as part of a multi-species research programme to develop methods for surveying marine mammals and seabird populations in aquaculture management areas. Two of the techniques, involving continuous time- lapse photography of mussel farms and boat-based surveys through coastal farms were developed for this study. Time- lapse cameras showed that mussel farms buoys were used by king shags as temporary resting sites only. King shags were recorded on 36% of the farms (n = 44) from 13 surveys within inner Admiralty Bay. The low number of sightings within mussel farms suggests that farms are not important foraging or resting areas for king shags, at least in Admiralty Bay. The foraging range and density of king shags was not known before farms were developed, so no direct comparison or impact assessment can be made. Boat-based surveys were used to estimate the density of foraging shags, which showed that daily locations of foraging birds at sea can vary considerably on consecutive days and over the season. Previous environmental surveys to assess impacts of mussel farms on foraging areas are therefore unlikely to adequately represent the entire foraging range or most important feeding areas. The number of breeding pairs, chicks and nests was also found to vary considerably at colonies, dependent on when counts were undertaken during their protracted breeding season. Open water mid-bay aquaculture (shellfish and finfish) potentially poses a greater threat to king shags than ‘coastal ribbon development’, in terms of loss of open water habitat from farm structures, and loss of foraging habitat through modification to the water column (e.g., turbidity) and seabed. Given the lack of knowledge about the king shag population dynamics, diet and prey availability, there is an urgent requirement for more research to fill these gaps and also understand how we can conserve important shag feeding areas and associated marine environment through sustainable management of aquaculture.