Notornis

Ahuahu / Great Mercury Island is the largest of the Mercury Islands which enables habitat diversity that supports a diverse avifauna. From a combination of quantitative surveys over the past 15 years and qualitative observations over the past 5 years by permanently resident rangers, we list and describe 62 non-vagrant bird species recorded recently on Ahuahu. Reference is made to change over the …

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 breedin…

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 tran…

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…

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 (Ster…

We attempted to supplementally feed 11 wild tara iti (Sternula nereis davisae) chicks aged 6–41 days using live and dead gobies, triplefins, and post-migratory galaxiids. Chicks less than 9 days old did not pick up fish placed near them or take food from tweezers in situ; however, one chick rescued at 8 days old was successfully tweezer-fed. Chicks older than 23 days old took fish from plates and…

Tara iti (New Zealand fairy tern, Sternula nereis davisae) is New Zealand’s rarest endemic breeding bird. As part of the Tara Iti Recovery Programme a head-starting programme was trialled between 2020 and 2024. Here we describe techniques developed by Auckland Zoo to successfully hand-rear 25 tara iti chicks from 30 artificially incubated eggs. The methods described here have the potential to be …

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 persisten…

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…

Interspecific and intraspecific aggressive behaviours towards chicks are well documented across several avian taxa. Over the last 40 years, observational data on tara iti (New Zealand fairy tern, Sternula nereis davisae) has shown that chicks of tara iti are frequently attacked by conspecifics, and occasionally by other species. This study examines observational data from 11 breeding seasons (201…

Sex ratio bias can strongly influence the viability of a small population. In tara iti (New Zealand fairy tern, Sternula nereis davisae), long-term monitoring over 25 years revealed a shift from roughly balanced sex ratios to a pronounced male bias among adults. This skew does not originate at hatching, as chick sex ratios fluctuate around 1:1. Skewed sex ratios develop after fledging through sex…

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 …

The New Zealand fairy tern/tara iti (Sternula nereis davisae) (hereafter; tara iti) is Aotearoa’s rarest indigenous breeding bird. Knowledge of tara iti foraging behaviour is limited. We used coordinated observations of adult movements between nesting sites and foraging territories to quantify foraging trips during chick provisioning at Mangawhai, Northland, in the 2021/22 breeding season. Comple…