Abstract: The Pitcairn Islands support regionally significant seabird assemblages, yet long gaps in monitoring limit understanding of seabird breeding phenology and basic biology. Observations from Oeno Atoll and Henderson Island in September 2025 reveal the importance of eradicating invasive Polynesian rats (Rattus exulans) in 1997 and habitat structure and highlight the potential for asynchronous breeding in many species. Oeno now supports high breeding activity across multiple trophic and nesting guilds, with widespread evidence of recruitment and large colony sizes relative to pre-eradication estimates. Breeding phenology was often protracted or shifted later than previously reported, highlighting substantial temporal variability both within and among islands. In contrast, ground-nesting species on Henderson continue to experience low reproductive success, consistent with ongoing predation pressure from Polynesian rats. Patterns of absence or low detectability in several taxa further emphasise the challenges of short-duration surveys in systems dominated by asynchronous or subannual breeders. Collectively, these findings underscore Oeno’s importance as a recovering seabird stronghold and highlight the need for repeated, seasonally explicit surveys to resolve phenology, population trends, and ecosystem responses to management interventions.
Abstract: Tara iti (New Zealand fairy tern, Sternula nereis davisae) are one of Aotearoa New Zealand’s most endangered birds, with decades of conservation effort focused on population monitoring, predator control, and habitat protection. This study examined fish species available to and consumed by tara iti through seine-net surveys (2021–2024) at Waipū and Mangawhai estuaries, supported by direct feeding observations and photography of feeding events. Forty-three fish species were identified across the two sites. While fish community composition differed significantly between estuaries, most variation occurred within sites. Waipū supported a greater diversity of small-bodied indicator species and juveniles of diadromous or estuarine-dependent taxa, whereas Mangawhai was dominated by juvenile flounder and gurnard. All indicator species represent suitable prey for tara iti and their chicks, highlighting the role of estuaries during the breeding season. However, sampling effort remains biased toward east coast estuaries and summer months, underscoring the need for broader temporal and spatial surveys.
Abstract: In New Zealand there are numerous ground-nesting sea and shore birds, many of which face similar threats to their nesting success. Threats include environmental conditions such as tidal inundation, damaging weather events and sand movement – challenges that are expected to worsen with ongoing climate change. Among the most vulnerable of these species is the New Zealand fairy tern / tara iti (Sternula nereis davisae). Nest protection and habitat enhancement methods including shell patch creation, sandbagging, dykes/trenches and dissuasion measures were used to protect tara iti nests from environmental threats at the four main breeding sites in Northland and Auckland. The success of these techniques means fewer nest manipulations were required, and the overall rate of nest success increased e.g., 68% (n=40) of nests were successful on created patches at Mangawhai. These techniques may also be useful for the protection of other ground-nesting coastal bird species.
Abstract: Understanding the progression to foraging independence in captive-reared tara iti (New Zealand fairy tern, Sternula nereis davisae) is vital for improving release strategies for this critically endangered taxon. We present the first detailed account of post-fledging foraging milestones for 12 captive-reared juveniles that were released during the 2023-24 and 2024-25 breeding seasons. Observations revealed a predictable sequence of behavioural development: fledging beyond the release pen occurred at an average of 26 days (range 25–28), first successful wild fish capture at 45 days (range 31–62), and juveniles began spending full days away from the release site at an average 51 days (range 41–58), with complete independence, defined as absence for more than five consecutive days and no reliance on supplementary feeding, achieved at approximately 62 days (range 46–80). These findings provide benchmarks for assessing post-release competence and highlight the importance of structured soft-release and supplementary feeding in supporting the transition to independent foraging.
Abstract: Seabirds are increasingly threatened by habitat loss, predation, disturbance, and climate change. Artificial nesting structures, such as floating rafts, elevated platforms, and dredge islands, have been trialled to mitigate these pressures, but effectiveness varies across species and contexts. Evaluating these interventions is crucial for developing evidence-based strategies, particularly for the critically endangered New Zealand fairy tern (tara iti, Sternula nereis davisae). This article reviews 33 studies on the uptake and breeding outcomes of artificial nesting structures, with implications for enhancing breeding success of tara iti. Floating rafts were the most common artificial structures and were generally effective for colonial terns when stabilised and maintained, but there was little to no evidence for their use by solitary or low-density breeding species. Elevated platforms had mixed success yet may support semi-colonial or solitary species when designed with natural substrates and predator protection. Dredge islands offered extensive long-term habitat but required major investment and ongoing management to prevent vegetation succession and ecological impacts. Overall, breeding productivity on these structures depended on species-specific design, proximity to foraging areas, and consistent maintenance.
Abstract: The critically endangered tara iti (Sternula nereis davisae), New Zealand’s rarest endemic bird, faces ongoing threats from habitat loss, predation, and climate change. Conservation efforts have included captive rearing and release programs, yet post-release survival and dispersal patterns remain poorly understood. This study presents the first satellite tracking data using lightweight Argos transmitters of three juvenile captive-reared tara iti. Our aim was to assess habitat use patterns, dispersal distances, site fidelity and diel movement. The tracked individuals exhibited varied movement patterns, including a large proportion of time around historically important roosting sites for tara iti. However, they also used previously unidentified areas, including the length of the Wairoa River. Tracked individuals also travelled longer distances than previously reported, as far as Thames, Cape Reinga, and New Plymouth. These results highlight the lack of knowledge around tara iti movement ecology and the utility of satellite tagging. However, key questions remain regarding the extent to which these movement patterns reflect those of wild-reared juveniles and whether similar behaviours are exhibited by adult tara iti.
Abstract: Conservation of the critically endangered New Zealand fairy tern (Sternula nereis davisae) has focused on predator control, habitat management, and intensive monitoring. However, intra-specific social dynamics at nest sites can also influence breeding success. This observational study examines aggression between adults when a female mates with more than one male or when an unpaired male persistently attends a nest. Using detailed observations from Waipū in 2015-16, supported by comparative cases from Te Ārai (2019-20) and Waipū (2020-21), we describe behaviours that escalate aggression: repeated copulation near the nest, establishment of micro-territories within the site, body-to-body fights, chick-directed pecking, and disruption of provisioning. These behaviours increased risk to chicks when pecking occurred or when feeding patterns were disrupted, and appeared to impose endurance costs on males attending nests. Understanding these interactions is important for management, as they may represent conditional strategies balancing food benefits against risks to chick survival and social stability.