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Rehabilitation of wildlife can be a meaningful conservation technique if rehabilitated animals contribute to the breeding population. Endangered Yellow-eyed Penguins (Megadyptes antipodes) are declining on South Island, New Zealand, where modelling published in 2017 predicted their extirpation by 2043. Four management plans dating back to 1989 have been implemented in attempts to mitigate threats. The first three plans overlooked rehabilitation whereas the most recent, published in 2020, regarded rehabilitation as essential to save the South Island population. We assess the outcome of four decades of management of Yellow-eyed Penguins at Moeraki, southeast South Island, by Penguin Rescue, a volunteer conservation organisation. Here, nest numbers have fluctuated but overall increased at a long-term annual average of 5%. Their proportion of the southeast South Island total rose from 1% (six of about 453 nests) in 1982 to 26% (43 of about 166 nests) in 2021. Since 1986 our management has included rehabilitation of all juvenile or adult Yellow-eyed Penguins we encountered locally with life-threatening injuries, emaciation or sickness, with 590 of these marked before release from our rehabilitation facility. We accounted for the effect of rehabilitation on nest numbers by subtracting the number of rehabilitated female breeders and their female descendants from the total number of female breeders. Without rehabilitation nest numbers at Moeraki in 2021 probably would have remained similar to the initial six nests in 1982 instead of the seven-fold increase through four decades. We conclude that rehabilitation is an effective management technique for this species. [ABSTRACT FROM AUTHOR]

Identifying variation in survival probabilities is fundamental to understanding population dynamics. We quantified variation in survival of Little Penguins (Eudyptula minor) at Oamaru, New Zealand, over 19 years from 1993–2011. Specifically survival in relation to age and breeding status were investigated. We used a multi-state capture-mark-recapture model to examine survival and recapture probabilities of known age penguins flipper-banded as chicks, and breeding penguins of unknown age banded as adults. The survival probability of Little Penguins in their first year averaged 0.42 and was lower than all older ages. The mean annual survival probability of breeding adult penguins was 0.86. The observed proportion of fledglings that later recruited into the breeding population in the study colony mirrored first-year survival estimates from the model. Survival was lower for pre-breeding penguins than for breeding penguins of the same age. We detected no significant effect of age on survival for breeding penguins. The comprehensive, long-term monitoring program in place at Oamaru resulted in very high recapture rates of breeding penguins that generated accurate estimates of survival. [ABSTRACT FROM AUTHOR]

Identifying variation in survival probabilities is fundamental to understanding population dynamics. We quantified variation in survival of Little Penguins (Eudyptula minor) at Oamaru, New Zealand, over 19 years from 1993-2011. Specifically survival in relation to age and breeding status were investigated. We used a multi-state capturemark- recapture model to examine survival and recapture probabilities of known age penguins flipper-banded as chicks, and breeding penguins of unknown age banded as adults. The survival probability of Little Penguins in their first year averaged 0.42 and was lower than all older ages. The mean annual survival probability of breeding adult penguins was 0.86. The observed proportion of fledglings that later recruited into the breeding population in the study colony mirrored first-year survival estimates from the model. Survival was lower for pre-breeding penguins than for breeding penguins of the same age. We detected no significant effect of age on survival for breeding penguins. The comprehensive, long-term monitoring program in place at Oamaru resulted in very high recapture rates of breeding penguins that generated accurate estimates of survival. [ABSTRACT FROM AUTHOR]

New Zealand sea lions ( Phocarctos hookeri) are threatened by incidental bycatch in the trawl fishery for southern arrow squid ( Nototodarus sloanii). An overlap between the fishery and foraging sea lions has previously been interpreted as one piece of evidence supporting resource competition for squid. However, there is currently no consensus about the importance of squid in the diet of New Zealand sea lions. Therefore, we investigated this importance independently of spatial and temporal differences in squid availability through a simultaneous study with sympatric New Zealand fur seals ( Arctocephalus forsteri), a species known to target arrow squid. Diet sampling at The Snares (48°01′S 166°32′E), subantarctic New Zealand, in February 2012 coincided with peak annual catch in the nearby squid fishery. Diets were deduced by analyses of diagnostic prey remains from scats (faeces) and casts (regurgitations). The contribution of each prey species to the diet was quantified using the per cent index of relative importance (% IRI) that combined frequency of occurrence, mass and number of prey items. Arrow squid was a minor component in sea lion scats (2 % IRI), and none was found in their casts. In contrast, arrow squid was the major component in fur seal scats and casts (93 and 99 % IRI, respectively). This study found that New Zealand sea lions ate minimal squid at a time when squid was clearly available as evidenced by the diet of New Zealand fur seals; hence, there was no indication of resource competition between sea lions and the squid fishery. [ABSTRACT FROM AUTHOR]

Data-logging devices are commonly used to study the foraging behaviour of individual seabirds. Such studies need to examine the potential effects of using devices on instrumented individuals, not only for ethical reasons but also to ensure the validity of data gathered. We studied the effects of two types of device (time-depth recorder and global positioning system) on little penguins ( Eudyptula minor) during the 2010 and 2011 breeding season at Oamaru, New Zealand. Mixed-effect models were used to test for effects of devices by comparing changes in body weight, chick growth and breeding performance between instrumented and control individuals. We found no detectable effects of the attached devices on body weight change, hatching success, fledging success, chick growth parameters or adult survival. We conclude that it is possible to attach data-logging devices to adult little penguins for extended periods during the breeding season with minimal impacts. [ABSTRACT FROM AUTHOR]

The link between poor reproductive success and diet was investigated in yellow-eyed penguins Megadyptes antipodes, by assessing diet at two localities separated by about 30 km: the north coast of Stewart Island where breeding success is low (0.38-0.67 chicks per pair in recent years), and Codfish Island where breeding success is higher (0.96-1.51 chicks per pair), and relating this to published data from South Island localities, where average breeding success was 1.1 chicks per pair. Diet composition, meal sizes and energetic content of meals and prey were determined from stomach contents, and stable isotope analyses of chick down, fledgling feathers and adult blood provided information on diet throughout the fledging period. The high proportion of stomachs that were empty or lacked diagnostic remains reduced sample size considerably, and variability between samples reduced the power to detect significant differences in meal size, proportions of empty stomachs and prey diversity of meals. Energetic content of Stewart Island meals was less than Codfish Island meals, and there was a non-significant trend for smaller meal sizes and reduced prey diversity among Stewart Island samples. Both localities had lower prey diversity and smaller meals than South Island penguins. Blue cod Parapercis colias accounted for 99% of prey biomass in Stewart Island and 70% in Codfish Island stomach samples, where 27% of prey biomass was opalfish Hemerocoetes monopterygius. Isotopic mixing models carried out on larger sample sizes indicated that opalfish comprised a large proportion of the diet at both locations, with adults selectively provisioning chicks with opalfish while feeding mainly on blue cod themselves. We suggest the large blue cod consumed by Codfish Island and Stewart Island penguins, larger than those consumed by South Island penguins, is difficult to transfer to chicks by regurgitation. Oyster dredging around Stewart Island may have reduced the availability and abundance of alternative prey to Stewart Island penguins. [ABSTRACT FROM AUTHOR]

The article discusses research on the effectiveness of rehabilitation for resident breeders as a tool to increase the population size of endangered yellow-eyed penguins or Megadyptes antipodes. The researchers monitored resident breeders treated at the rehabilitation facility of Penguin Place, an eco-tourism venture near Dunedin, New Zealand. The findings showed that the average annual survival for adult females increased only by seven percent due to rehabilitation. It was concluded that the population size of the species could be enhanced by rehabilitation only at managed locations.

The article presents a study which evaluates the keratinous mandibles in prey remains of the Macroctopus maorum, the largest octopod in Australasia in order to estimate the size of the octopus. Ninety M. maorum were collected from the coastline of New Zealand in order to measure the ventral and dorsal mantle lengths, total length and body mass through their upper and lower beaks. Results show that equations including the transparent strip applied to beaks would decrease its body mass by c. 25%.

This study presented evidence that creates a quandary for conservation management: predation by one threatened species, New Zealand sea lion (Phocarctos hookeri), threatens the viability of another threatened species, yellow-eyed penguin (Megadyptes antipodes), at Otago Peninsula, South Island, New Zealand. Otago Peninsula holds the largest population of yellow-eyed penguins on South Island and the only breeding population of New Zealand sea lions on the New Zealand mainland. New Zealand sea lions here represent the vanguard of re-colonisation within their prehistoric range, with nine females and 50–70 males resident in 2005. The initial indication of a potential problem was an attack on a yellow-eyed penguin by a New Zealand sea lion witnessed in 1996. The majority of 20 records for attacks were at two neighbouring sites, where they coincided with decreases in penguin nest numbers and adult annual survival. In contrast, penguin nest numbers increased at a third site, the main base for male sea lions at Otago Peninsula. Evidence from prey remains indicated that male sea lions did not eat yellow-eyed penguins but that females ate 20–30 annually, with one individual possibly responsible for most kills. Modelling indicated that the penguin population at any one site could not remain viable if it was the sole source of penguins killed. The dilemma is either to do nothing, and risk collapse of the Otago Peninsula population of yellow-eyed penguins, or to take action against known culprits, and risk failure in re-colonisation of the New Zealand mainland by New Zealand sea lions. [Copyright &y& Elsevier]

Management plans for threatened or recovering large vertebrate species that are increasing in population size and range focus on the establishment of viable populations within set temporal limits. New Zealand (Hookers) sea lions (Phocarctos hookeri) were declared a threatened species in 1997, and New Zealand legislation requires that threatened species of marine mammals must be managed to reduce human-induced mortality and achieve a non-threatened status within 20 years. The present breeding distribution of P. hookeri is highly localised, with over 95% of total annual pup production located at Auckland Islands and almost all of the remainder at Campbell Island. Breeding elsewhere has been ephemeral or restricted to <10 adult females. The only recorded sustainable breeding at a new location has been at Otago, South Island, New Zealand. This breeding population consisted of a total of four breeding females in 2002 and is derived from one immigrant female that gave birth to her first pup in the 1993/1994 breeding season. The New Zealand Department of Conservation management plan specifies that to achieve a non-threatened status P. hookeri (1) at Otago must increase in the number of breeding females to &ges;10, and (2) must establish &ges;two new breeding locations within the 20-year time frame, each with &ges;10 breeding females. This study 1) projects the population growth trends at a new location (Otago) to see if it will achieve &ges;10 breeding females within the legislated time frame, and (2) examines the likelihood that other breeding locations will establish elsewhere given the demographic information available for this species. We present 20 deterministic and three stochastic Leslie matrix model scenarios for female population growth for the initial years following the start of breeding at a new location. Our results indicate that (1) a new breeding population derived from one immigrant female is unlikely to reach 10 breeding females in 20 years; this duration is more likely to be 23–41 years (deterministic models) or 23–26 years (stochastic model), (2) the likelihood of two new sites establishing within 20 years is unquantifiable, but the probability is low, and (3) if the legislated outcome and time limit are not revised in the population management plan, the feasibility and effectiveness of re-locating young females could be investigated. [Copyright &y& Elsevier]

Little Penguin ( Eudyptula minor) populations on the south-eastern coastline of the South Island, New Zealand, thrive at locations where they are protected from predation by introduced mammals and disturbance by people. Our objective was to investigate the reproductive performance of a population of Little Penguins at Oamaru over a period of 19 years. Long-term monitoring of the population began in 1993 and involved a weekly check of all nests in the breeding colony to record the numbers of adult penguins, eggs and chicks present. All breeding adults and fledged chicks were flipper-banded. Breeding seasons with an early onset of egg-laying had more double brooding. Annual breeding success through 19 breeding seasons (1994-2012) averaged 1.89 chicks per female, the highest recorded for the species. The study showed that an early onset of egg-laying and the occurrence of double brooding resulted in high breeding success at the Oamaru population. [ABSTRACT FROM AUTHOR]

The adzebills (Aptornithidae) were an ancient endemic lineage of large flightless Gruiformes that became extinct shortly after Polynesian settlement of New Zealand. The diet and ecology of these enigmatic birds has long been a matter for conjecture, but recent stable isotope analyses of bones of the North Island adzebill (Aptornis otidiformis) have indicated that adzebills may have been predatory. Here, we add to our understanding of adzebill ecology by providing the first stable isotope analyses of South Island adzebill (A. defossor) bones from two Holocene deposits. We interpret the results within frameworks of stable isotope measurements on bones of faunal species with known diets and from the same deposits (thereby mitigating regional effects on isotope values). Our results strongly support the hypothesis that adzebills had a high trophic position. Considered alongside the unique skeletal adaptations of adzebills and the distribution of the species during the Holocene, we suggest that adzebills were most likely terrestrial predators restricted to dry podocarp forests and may have specialised in dismantling rotting logs to obtain invertebrates and/or excavating burrowing animals such as tuatara or the chicks of burrow-nesting birds. [ABSTRACT FROM AUTHOR]

Leucocarbo shags are a species-rich seabird clade exhibiting a southern circumpolar distribution. New Zealand's endemic Stewart Island shag, Leucocarbo chalconotus (G. R. Gray, 1845), comprises two regional groups (Otago and Foveaux Strait) that show consistent differences in relative frequencies between pied (black and white) and bronze (wholly dark) plumages, the extent and colour of facial carunculation, body size (based on postcranial morphometrics), and breeding season. Moreover, previous genetic research on modern and historical specimens utilizing mitochondrial DNA control-region sequences has also shown that the Otago and Foveaux lineages may not be sister taxa; instead, in several analyses the Otago lineage is sister to the endemic Chatham Island shag, Leucocarbo onslowi (Forbes, 1893). We present new ancient DNA analyses of the type specimens for the Otago and Foveaux Strait lineages of L. chalconotus, including a phylogenetic reanalysis of the available ancient, historical, and modern control-region sequence data for these lineages (including L. onslowi), and additional statistical analyses incorporating new morphometric characters. These analyses indicate that under the diagnosable species concept the two lineages of Stewart Island shag represent two separate species, which we now recognize as the Otago shag, L. chalconotus (G. R. Gray, 1845), and the Foveaux shag, Leucocarbo stewarti (Ogilvie-Grant, 1898). [ABSTRACT FROM AUTHOR]

Unravelling prehistoric anthropogenic impacts on biodiversity represents a key challenge for biologists and archaeologists. New Zealand's endemic Stewart Island Shag ( Leucocarbo chalconotus) comprises two distinct phylogeographic lineages, currently restricted to the country's south and southeast. However, fossil and archaeological remains suggest a far more widespread distribution at the time of Polynesian settlement ca. 1280 AD, encompassing much of coastal South Island. We used modern and ancient DNA, radiocarbon dating, and Bayesian modelling, to assess the impacts of human arrival on this taxon. Our analyses show that the southeast South Island (Otago) lineage was formerly widespread across coastal South Island, but experienced dramatic population extinctions, range retraction and lineage loss soon after human arrival. By comparison, the southernmost (Foveaux Strait) lineage has experienced a relatively stable demographic and biogeographic history since human arrival, retaining much of its mitochondrial diversity. Archaeological data suggest that these contrasting demographic histories (retraction vs. stability) reflect differential human impacts in mainland South Island vs. Foveaux Strait, highlighting the importance of testing for temporal and spatial variation in human-driven faunal declines. [ABSTRACT FROM AUTHOR]

New Zealand's endemic Stewart Island Shag (Leucocarbo chalconotus) comprises two regional groups (Otago and Foveaux Strait) that show consistent differentiation in relative frequencies of pied versus dark-bronze morphotypes, the extent of facial carunculation, body size and breeding time. We used modern and ancient DNA (mitochondrial DNA control region one), and morphometric approaches to investigate the phylogeography and taxonomy of L. chalconotus and its closely related sister species, the endemic Chatham Island Shag (L. onslowi). Our analysis shows Leucocarbo shags in southern New Zealand comprise two well-supported clades, each containing both pied and dark-bronze morphs. However, the combined monophyly of these populations is not supported, with the L. chalconotus Otago lineage sister to L. onslowi. Morphometric analysis indicates that Leucocarbo shags from Otago are larger on average than those from Foveaux Strait. Principal co-ordinate analysis of morphometric data showed substantial morphological differentiation between the Otago and Foveaux Strait clades, and L. onslowi. The phylogeographic partitioning detected within L. chalconotus is marked, and such strong structure is rare for phalacrocoracid species. Our phylogenetic results, together with consistent differences in relative proportions of plumage morphs and facial carunculation, and concordant differentiation in body size and breeding time, suggest several alternative evolutionary hypotheses that require further investigation to determine the level of taxonomic distinctiveness that best represents the L. chalconotus Otago and Foveaux Strait clades. [ABSTRACT FROM AUTHOR]