Knowledge of seabird diets is an important factor in determining their vulnerability to human-driven change in marine ecosystems. The northern Aotearoa New Zealand marine ecosystem is home to a large community of procellariiform seabirds whose breeding schedules overlap. This is expected to create competition for similar resources among these species across space and time; however, to what extent is not known. We investigated the diets of fairy prions Pachyptila turtur and Buller’s Ardenna bulleri , fluttering Puffinus gavia , and little shearwaters Puffinus assimilis haurakiensis breeding in the region using bulk stable isotope analysis of δ 15 N and δ 13 C. The aims of this study were to (1) determine the stable isotope niche space of 4 species with temporal breeding overlap and assumed spatial foraging overlap; (2) investigate inter-annual consistency within species; and (3) investigate intra-annual shifts across the breeding season for 2 species. Results suggest resource partitioning through divergence in trophic level of foraging, and spatial overlap that was expected from observations of mixed foraging flocks. Inter-annual changes in one species suggest a capacity to prey-shift, but at the cost of greater overlap with the other species. Intra-annual shifts were consistent across the duration of the study, indicating a strategic or availability-related shift to higher trophic-level prey in energetically important stages of the breeding season. Dietary flexibility may enable resilience to change in prey availability resulting from natural and anthropogenic effects, at the cost of exposure to greater competition with other seabird species. This may be a source of pressure for recovering seabird populations in the region, if marine resources are limited.

Assessing changes in species trophic ecology over a large timescale is essential not only to measure how anthropogenic impacts modify ecological processes but also to measure the effectiveness of wildlife conservation actions. The North Island (NI) and South Island (SI) Saddlebacks, or t & imacr;eke, Philesturnus rufusater and P. carunculatus, respectively, are two of the species undergoing the most effective conservation actions in Aotearoa New Zealand after large-scale management of introduced mammals and successful translocation of individuals. Here we used stable isotope analysis of carbon and nitrogen to determine isotopic niche metrics and assess whether the trophic ecologies of NI and SI saddlebacks differ over time. We sampled contour feathers from 33 NI saddleback (spanning 1880-2011) and 36 SI saddleback (spanning 1826-2012) specimens, dividing them into three temporal groups for analysis, i.e. historical, bottleneck, and post-translocation periods. The isotopic niche widths of both saddleback species differed significantly between the temporal groups, with different trends for each species. The NI saddleback showed an expansion in the post-translocation period niche width, indicating this species was probably on the verge of complete collapse after the intensification of anthropogenic impacts in New Zealand. In contrast, the SI saddleback showed a contraction in the post-translocation period niche width, which may reflect a less diverse habitat in terms of food resources. This demonstrates that conservation measures, although successful in terms of population re-establishment, could not completely restore the historical trophic niche of this endangered species. Additionally, SI saddlebacks had higher stable isotope values than NI saddlebacks, suggesting that the two species differ in their trophic ecology. We demonstrated that ecological metrics of successful conservation actions can also be measured through stable isotope analysis of museum specimens, in addition to providing information that supplements current knowledge of the species.

The species diversity in the family Emeidae of the extinct New Zealand moa (Aves: Dinornithiformes) remains problematic and unresolved because so far there has been little integration of genetic, morphometric, and geographical information underpinned by solid radiocarbon chronologies. Here we re-investigate variation within the genus Euryapteryx using ancient mitochondrial genetics and morphometric analysis of leg bone lengths (femur, tibiotarsus, and tarsometarsus) from samples spanning the entire geographical range of the genus, in geological age from the late Pleistocene to their extinction in the past 1000 years. Our analyses revealed disparity between the results of genetics and morphometrics. We identified geographically distinct phylogenetic lineages, whose distributions were unrelated to morphometric patterns. The morphometric results do not support the current recognition of North and South Island subspecies but are instead consistent with the geographical and climatic histories of populations. This highlights the value of population-level morphometrics in assessing phenotypic response to changing environments, independent of descent. Furthermore, our results underline the value of the unique evolutionary system provided by New Zealand moa in separating the effects of climate, topography, tectonics, and volcanism on the evolution of large vertebrates.

Coastal seabirds are valuable indicators of ecological change in nearshore marine systems impacted by human activities. This study examined how human population growth and urban expansion have influenced the long-term dietary patterns of karoro (southernblack-backed gullLarus dominicanus) inAuckland, Aotearoa | New Zealand. Specifically, we assessed whether increasing urbanisation has led to a dietary shift from marine-based prey to greater reliance on terrestrial and anthropogenic food sources. Contemporary diet composition was analysed using regurgitated pellets from two island breeding sites (Rangitoto and Tiritiri Matangi) in the Hauraki Gulf-sites differing in proximity to urban influence-and an urban roosting site at Western Springs Park. To assess long-term dietary trends, we conducted nitrogen stable isotope analysis of feathers from museum specimens spanning 109 years and collagen from contemporary karoro bones and subfossil bones from Tokerau Beach predating human arrival in Aotearoa. Pellet analysis indicated a diverse diet comprising marine vertebrates, invertebrates, and terrestrial or anthropogenic food sources, with city proximity influencing dietary composition. Stable isotope analysis revealed significant changes in karoro trophic ecology over the past century with birds shifting from a predominantly marine-based diet to one more reliant on terrestrial food, likely due to declining marine prey and increased urban food availability. Stable isotope data from ancient bones indicated that pre-human karoro were obligate coastal marine predators and scavengers, occupying a higher trophic level than their modern counterparts. These findings provide insight into how urbanisation and ecological change have shaped karoro diets over time.

Animal telemetry is maturing into a viable method for observing the ocean as it can be used to monitor both environmental conditions and biological metrics along the movement trajectories of marine animals. As part of the Cormorant Oceanography Project, we have augmented a biologging tag with an external fast response temperature sensor to collect ocean temperature profiles from the backs of foraging marine birds. Cormorants dive between 50 and 250+ times a day to forage for prey so they can provide hard-to-match temporal and spatial coverage of coastal ocean conditions within their foraging areas. We process tag measurements to obtain fundamental oceanographic data (e.g., temperature profiles, bottom soundings, surface current measurements). Together, we have tracked 17 marine bird species (including two Spheniscus penguins spp. and a sea duck), originating from 17 countries and foraging along the edges of all major oceans. Tagged birds’ distribution included 191 MPAs in 26 countries, offering a unique ocean monitoring method to complement more widely used methods.

The Auckland Domain is the city’s oldest park and contains over 70 ha of contiguous, mature urban forest. Five-minute bird counts were made across one year within the domain forest in 2019 and 2020 and compared with counts conducted in 1987 and 1988, using the same methods and at the same survey sites, to investigate changes in the structure of the urban bird community. The abundance and species richness of native and introduced birds increased between the count years and there was structural change within the community driven by increases in the abundance of forest-adapted endemic species, tūī Prosthemadera novaeseelandiae, grey warbler Gerygone igata, and kererū Hemiphaga novaeseelandiae, and declines in generalist native species, silvereye Zosterops lateralis and fantail Rhipidura fuliginosa. Tūī showed the most profound increase in abundance between count years, reflecting regional conservation management of mainland and island forest habitats that benefit this highly mobile species. Increased abundance of eastern rosella Platycercus eximius and common myna Acridotheres tristis also altered community structure between count years, indicative of ongoing colonization by these exotic species in the Auckland region since their introduction to the North Island. The fact that both these species compete with native taxa for nest cavities within forests is of concern. Our results reinforce the need to manage and protect maturing urban forests to enhance native bird populations. Such actions will also support the recovery of native bird populations at a landscape scale.

Aim: To identify the broad-scale oceanic migration routes ('marine flyways') used by multiple pelagic, long-distance migratory seabirds based on a global compilation of tracking data. Location: Global. Time Period: 1989-2023. Major Taxa Studied: Seabirds (Families: Phaethontidae, Hydrobatidae, Diomedeidae, Procellariidae, Laridae and Stercorariidae). Methods: We collated a comprehensive global tracking dataset that included the migratory routes of 48 pelagic and long-distance migrating seabird species across the Atlantic, Indian, Pacific and Southern Oceans. We grouped individuals that followed similar routes, independent of species or timings of migration, using a dynamic time warping clustering approach. We visualised the routes of each cluster using a line density analysis and used knowledge of seabird spatial ecology to combine the clusters to identify the broad-scale flyways followed by most pelagic migratory seabirds tracked to-date at an ocean-basin scale. Results: Six marine flyways were identified across the world's oceans: the Atlantic Ocean Flyway, North Indian Ocean Flyway, East Indian Ocean Flyway, West Pacific Ocean Flyway, Pacific Ocean Flyway and Southern Ocean Flyway. Generally, the flyways were used bidirectionally, and individuals either followed sections of a flyway, a complete flyway, or their movements linked two or more flyways. Transhemispheric figure-of-eight routes in the Atlantic and Pacific oceans, and a circumnavigation flyway in the Southern Ocean correspond with major wind-driven ocean currents. Main Conclusions: The marine flyways identified demonstrate that pelagic seabirds have similar and repeatable migration routes across ocean-basin scales. Our study highlights the need to account for connectivity in seabird conservation and provides a framework for international cooperation.

Plastic pollution is distributed patchily around the world's oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species.

The New Zealand storm petrel (NZSP; Fregetta maoriana ), thought to be extinct for over 150 years, was rediscovered in 2003. In 2013, a single NZSP breeding population was identified on Te Hauturu-o-Toi (Little Barrier Island) in the Hauraki Gulf off the east coast of Aotearoa New Zealand’s North Island. Expeditions in 2021 to the Far North of New Zealand identified numerous NZSP at-sea over 300 km from Te Hauturu-o-Toi, suggesting that another breeding colony may exist. Blood samples collected from NZSP in the Hauraki Gulf and the Far North were used to generate genomic data. These data were analysed to investigate if individuals from the Far North are genetically differentiated from NZSP from the Hauraki Gulf, and if any individuals from the two locations are close relatives. Analyses revealed that NZSP from the Far North and Hauraki Gulf are not genetically distinct, and possible second-degree relatives were identified between the locations. Genetic diversity estimates indicated low population diversity levels and low effective population size estimates. These results suggest that Te Hauturu-o-Toi may be the only NZSP breeding colony, and the Far North represents a foraging location for NZSP. Sex bias fluctuates through the year but is similar in the two locations, also supporting a lack of population structure and indicating little foraging location bias between the sexes. Further research is needed to confirm whether highly connected or recently established colonies exist. These results highlight the extinction risk for NZSP and the importance of conservation efforts on Te Hauturu-o-Toi.

Long-term changes in the life history and behaviour of seabirds during the non-breeding season can reflect shifts in environmental conditions. However, long-term marine studies are scarce, particularly on southern hemisphere seabirds. Here, we used moult scores from 86 Brown Skuas (Stercorarius antarcticus lonnbergi), a large predatory seabird breeding on the Chatham Islands, Aotearoa/New Zealand to model both the timing and duration of primary feather moult. In addition, we analysed stable isotope values (delta C-13 and delta N-15) from 62 modern (2014-16) and ten museum tail feathers. These data provide insights into the non-breeding behaviour of Brown Skua. Interestingly, our results show that the primary feather moult occurred prior to birds departing the colony, starting on average on 2 January +/- 5 days (SE). The average start of primary feather moult occurred five days prior to the end of breeding (7 January +/- 10 days (SD)) and 42 days before the birds departed the colony (13 February +/- 11 days (SD)). The average duration of primary feather moult was 189 +/- 14 days (SE). Importantly, low delta C-13 values in four females suggested that tail feather moult might also occur while skuas are at the colony. There was no difference in tail feather delta C-13 and delta N-15 values between any pairwise comparison of modern and museum years. However, values of delta N-15 from tail feathers sampled in 2014 were different from those sampled in 2015 and 2016. This large annual variation in delta N-15 values from tail feathers over such a short period makes long-term comparisons difficult to interpret, particularly between years with low sample sizes. While the stable isotope analyses of tail feathers are informative, we recommend future studies of skuas sample the primary coverts rather than tail feathers.

The black-winged petrel (Pterodroma nigripennis) is an abundant procellariiform seabird breeding on islands in the Southwest Pacific and Indian Oceans. The largest populations breed in the New Zealand region where at sea movements and breeding behaviour across the annual cycle remain poorly described. We used geolocators with saltwater immersion sensors to track movements and characterise breeding behaviour of P. nigripennis from three New Zealand breeding colonies (Raoul, Burgess, and Rangatira Islands) across a 1,600 km latitudinal gradient. Breeding extended from November to June and in Raoul Island birds pre-laying, incubation, and chick rearing periods lasted 36, 50, and 85 days respectively. During breeding, birds from all colonies foraged within waters of the subtropical convergence zone which for Raoul, required one-way foraging trips of over 1,500 km. During March-June birds migrated east, then north and northwest to core foraging zones predominantly within the North Pacific subtropical front, but a small number of birds also wintered south of Hawaii in equatorial waters. Birds were predominantly nocturnally active during breeding and non-breeding seasons indicating a dependence of nocturnally available prey. These data contribute to a growing understanding of the unprecedented movements and potential partitioning of habitat by Australasian Pterodroma petrels within the Pacific Ocean and we summarise and discuss available data.

Grey-faced Petrels (Pterodroma gouldi) are a colonial burrowing seabird predominantly nesting on offshore islands of the upper North Island of New Zealand. We studied their annual breeding biology and the impact of Southern Oscillation Index climatic effects by measuring colony productivity and chick growth rates from 2011 to 2015 on Te Hāwere-a-Maki as unfavorable warmer La Niña conditions changed to favorable cooler El Niño conditions. Across all five years, annual chick hatching consistently occurred within a one-week period at the end of August but fledging variably occurred over a three-week period following Christmas. Because ship rats are pest controlled on Te Hāwere-a-Maki, we found only a slight reduction in breeding success with nearby predator-free islands. However, chick growth and fledging rates were significantly higher under El Niño conditions occurring towards the end of our study, rather than La Niña conditions at the start of our study. Our regular handling of chicks for monitoring had no discernible impact compared to a set of control chicks. The combined impacts of annual variation in predation and climate mean the Grey-faced Petrel colony on Te Hāwere-a-Maki maintains a constant population size of around 100 burrows.

The cover image is based on the Letter AVONET: morphological, ecological and geographical data for all birds by Tobias et al., https://doi.org/10.1111/ele.13898. The sword-billed hummingbird (Ensifera ensifera) is exquisitely adapted to its trophic niche as an aerial pollinator of flowerings plants (angiosperms) in the high Andes. A new global dataset of detailed ecomorphological traits for all birds offers a resource with numerous potential uses in ecology, evolution, and conservation biology. Image Credit: Cover Image © Oliver Krüger. Reproduced with permission.

Functional traits offer a rich quantitative framework for developing and testing theories in evolutionary biology, ecology and ecosystem science. However, the potential of functional traits to drive theoretical advances and refine models of global change can only be fully realised when species-level information is complete. Here we present the AVONET dataset containing comprehensive functional trait data for all birds, including six ecological variables, 11 continuous morphological traits, and information on range size and location. Raw morphological measurements are presented from 90,020 individuals of 11,009 extant bird species sampled from 181 countries. These data are also summarised as species averages in three taxonomic formats, allowing integration with a global phylogeny, geographical range maps, IUCN Red List data and the eBird citizen science database. The AVONET dataset provides the most detailed picture of continuous trait variation for any major radiation of organisms, offering a global template for testing hypotheses and exploring the evolutionary origins, structure and functioning of biodiversity.

Globally, human population growth, its associated pollution and the vast scale of industrialised fisheries are having negative impacts on oceanic food webs, affecting top predators such as seabirds. We used stable isotope (δ15N and δ13C) analyses of feathers to investigate the contemporary structure and long-term changes in a near-shore community of 5 seabird species in northern Aotearoa New Zealand. Feathers were collected from museum specimens or live individuals (collected between 1878 and 2019) in Tīkapa Moana, the Hauraki Gulf, a marine habitat increasingly threatened by overfishing and urbanisation. To tease out the effects of baseline ecosystem versus seabird distributional changes, we analysed muscle isotope values of forage fishes collected over 43 yr (1976-2019) and provide isotopic data from contemporary prey species sampled within the region. Contemporary δ15N and δ13C values were consistent with existing data on diet and foraging distribution of the 5 seabird species. Values of δ15N declined in only 1 of 5 species studied, suggesting little change in the trophic position of the other species over time. However, δ13C values declined in 3 species, and a lack of change in the δ15N and δ13C values of forage fish suggests that this change is reflective of a behavioural shift in the distribution of the birds. However, changes in isotopic baselines over the sampling period cannot be ruled out and require further investigation. Our results demonstrate the value of stable isotope analyses of contemporary and archived samples as a cost effective, non-invasive method for monitoring coastal seabirds in a changing world.

Every year, billions of birds undertake extensive migrations between breeding and non-breeding areas, facing challenges that require behavioural adjustments, particularly to flight timing and duration. Such adjustments in daily activity patterns and the influence of extrinsic factors (e.g., environmental conditions, moonlight) have received much more research attention in terrestrial than marine migrants. Taking advantage of the widespread deployment in recent decades of combined light-level geolocator-immersion loggers, we investigated diel organisation and influence of the moon on flight activities during the non-breeding season of 21 migrant seabird species from a wide taxonomic range (6 families, 3 orders). Migrant seabirds regularly stopped (to either feed or rest) during migration, unlike some terrestrial and wetland birds which fly non-stop. We found an overall increase for most seabird species in time in flight and, for several species, also in flight bout duration, during migration compared to when resident at the non-breeding grounds. Additionally, several nocturnal species spent more of the day in flight during migration than at non-breeding areas, and vice versa for diurnal species. Nocturnal time in flight tended to increase during full moon, both during migration and at the non-breeding grounds, depending on species. Our study provides an extensive overview of activity patterns of migrant seabirds, paving the way for further research on the underlying mechanisms and drivers.

SummaryCook’s Petrel Pterodroma cookii is an endemic New Zealand seabird that has experienced a large range decline since the arrival of humans and now only breeds on two offshore islands (Te Hauturu-o-Toi/Little Barrier Island and Whenua Hou/Codfish Island) at the extreme ends of its former distribution. Morphological, behavioural, and mitochondrial cytochrome oxidase 1 (CO1) sequence data led a previous study to recognise the two extant populations as distinct conservation management units. Here, we further examine the genetic relationship between the extant populations using two nuclear introns (β-fibint7 and PAX). Using one mitochondrial locus (CO1), we also investigate the past distribution of a single nucleotide polymorphism (SNP) that differentiates the modern populations using bone and museum skins sourced from within its former range across New Zealand’s North and South Islands. We found significant population genetic structure between the two extant Cook’s Petrel populations for one of the two nuclear introns (β-fibint7). The mitochondrial DNA CO1 analysis indicated that the SNP variant found in the Codfish Island population was formerly widely distributed across both the North and South Islands, whereas the Little Barrier Island variant was detected only in North Island samples. We argue that these combined data support the recognition of the extant populations as different subspecies. Previous names for these taxa exist, thus Cook’s Petrel from Little Barrier Island becomes Pterodroma cookii cookii and Cook’s Petrel from Codfish Island becomes P. c. orientalis. Furthermore, we suggest that both genetic and non-genetic data should be taken into consideration when planning future mainland translocations. Namely, any translocations on the South Island should be sourced from Codfish Island and future translocations on the North Island should continue to be sourced from Little Barrier Island only.