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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 (δ13C and δ15N) 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 δ13C 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 δ13C and δ15N values between any pairwise comparison of modern and museum years. However, values of δ15N from tail feathers sampled in 2014 were different from those sampled in 2015 and 2016. This large annual variation in δ15N 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.

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.

Tobias, Joseph A., Sheard, Catherine, Pigot, Alex L., Devenish, Adam J. M., Yang, Jingyi, Sayol, Ferran, Neate‐Clegg, Montague H. C., Alioravainen, Nico, Weeks, Thomas L., Barber, Robert A., Walkden, Patrick A., MacGregor, Hannah E. A., Jones, Samuel E. I., Vincent, Claire, Phillips, Anna G., Marples, Nicola M., Montaño‐Centellas, Flavia A., Leandro‐Silva, Victor, Claramunt, Santiago, Darski, Bianca, Freeman, Benjamin G., Bregman, Tom P., Cooney, Christopher R., Hughes, Emma C., Capp, Elliot J. R., Varley, Zoë K., Friedman, Nicholas R., Korntheuer, Heiko, Corrales‐Vargas, Andrea, Trisos, Christopher H., Weeks, Brian C., Hanz, Dagmar M., Töpfer, Till, Bravo, Gustavo A., Remeš, Vladimír, Nowak, Larissa, Carneiro, Lincoln S., Moncada R., Amilkar J., Matysioková, Beata, Baldassarre, Daniel T., Martínez‐Salinas, Alejandra, Wolfe, Jared D., Chapman, Philip M., Daly, Benjamin G., Sorensen, Marjorie C., Neu, Alexander, Ford, Michael A., Mayhew, Rebekah J., Fabio Silveira, Luis, Kelly, David J., Annorbah, Nathaniel N. D., Pollock, Henry S., Grabowska‐Zhang, Ada M., McEntee, Jay P., Carlos T. Gonzalez, Juan, Meneses, Camila G., Muñoz, Marcia C., Powell, Luke L., Jamie, Gabriel A., Matthews, Thomas J., Johnson, Oscar, Brito, Guilherme R. R., Zyskowski, Kristof, Crates, Ross, Harvey, Michael G., Jurado Zevallos, Maura, Hosner, Peter A., Bradfer‐Lawrence, Tom, Maley, James M., Stiles, F. Gary, Lima, Hevana S., Provost, Kaiya L., Chibesa, Moses, Mashao, Mmatjie, Howard, Jeffrey T., Mlamba, Edson, Chua, Marcus A. H., Li, Bicheng, Gómez, M. Isabel, García, Natalia C., Päckert, Martin, Fuchs, Jérôme, Ali, Jarome R., Derryberry, Elizabeth P., Carlson, Monica L., Urriza, Rolly C., Brzeski, Kristin E., Prawiradilaga, Dewi M., Rayner, Matt J., Miller, Eliot T., Bowie, Rauri C. K., Lafontaine, René‐Marie, Scofield, R. Paul, Lou, Yingqiang, Somarathna, Lankani, Lepage, Denis, Illif, Marshall, Neuschulz, Eike Lena, Templin, Mathias, Dehling, D. Matthias, Cooper, Jacob C., Pauwels, Olivier S. G., Analuddin, Kangkuso, Fjeldså, Jon, Seddon, Nathalie, Sweet, Paul R., DeClerck, Fabrice A. J., Naka, Luciano N., Brawn, Jeffrey D., Aleixo, Alexandre, Böhning‐Gaese, Katrin, Rahbek, Carsten, Fritz, Susanne A., Thomas, Gavin H., Schleuning, Matthias (2022): AVONET: morphological, ecological and geographical data for all birds. Ecology Letters 25 (3): 581-597, DOI: 10.1111/ele.13898, URL: http://dx.doi.org/10.1111/ele.13898

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.

SummaryThe Beck’s Petrel Pseudobulweria beckii is a ‘Critically Endangered’ seabird whose breeding sites remain unknown. Historic observations suggest the species’ distribution is concentrated in the Bismarck Archipelago and particularly southern New Ireland. Over the course of two research expeditions in 2016 and 2017 we used on-land and at-sea observations, local interviews and satellite telemetry to understand the distribution of the species, its at-sea movements and potential breeding locations. Land-based and at-sea observations indicated that the area of Silur Bay in southern New Ireland was a significant site for Beck’s Petrel with numbers of birds increasing near shore prior to dusk and birds observed in spotlights over land. A local population is estimated to be in the low thousands. In 2017 a single Beck’s was captured at sea, fitted with a satellite transmitter and tracked for eight months. This bird maintained a core distribution off the south-east coast of New Ireland and north of Bougainville for 122 days. During the tracking period, the bird was located over land at night seven times; predominantly over southern New Ireland, where the signal was also lost for extended periods suggesting occupancy of an underground burrow. In August the bird migrated 1,400 km to a core pelagic habitat north of West Papua before the signal was eventually lost. Our combination of land- and sea-based observations and analysis of behaviour from satellite tracking supports the conclusion that a breeding site for Beck’s Petrel lies in the inland mountains of southern New Ireland and most likely in the high-altitude zone (> 2000 m) of the Hans Meyer Range. Further investigations are required to determine the exact location of breeding colonies in the mountains of southern New Ireland and the importance of a potential west Papuan non-breeding pelagic habitat for the species.

Common Diving Petrels (Pelecanoides urinatrix urinatrix) are distributed widely around coastal New Zealand and breed primarily on predator-free offshore islands. Despite their ubiquity, little is k...

Seabird foraging behaviour can reflect prey abundance at sea, and is influenced by stress hormone levels, thus providing a potential indicator of at-sea conditions. Using common diving petrels (Pelecanoides urinatrix, hereafter CDPs), a procellariform that preferentially forages on crustacean zooplankton, we sought to understand how spatially separate colonies responded behaviourally and physiologically to contrasting prey levels with a view to recruiting this species as an environmental indicator. In 2016, incubating CDPs from Tiritiri Matangi (− 36.59S; 174.88E, low levels of preferred prey) and Burgess (− 35.91S; 174.12E, high levels of preferred prey) Islands within the Hauraki Gulf, New Zealand, were tracked using GPS devices. We hypothesised that Tiritiri birds would exhibit greater foraging effort and higher stress hormone levels across the breeding season due to lower levels of available prey. Hidden Markov methods were used to model foraging effort, and prey trophic level (stable isotopes: δ13C and δ15N) and stress hormone levels (CORT) quantified in plasma samples. During incubation birds were spatially segregated when foraging. Tiritiri birds exerted more effort, chasing higher trophic level prey at larger distances from the colony, and had higher body weight and lower CORT than Burgess birds. However, bird CORT levels responded more to reproductive duties (peaking during chick rearing) as opposed to colony location, i.e. CORT was not consistently higher in Tiritiri birds. Although a snapshot, our findings illustrate the promise of integrating multiple parameters when recruiting seabirds as ocean indicators, resulting in improved resolution of future monitoring programmes based upon them.

New Zealand’s endemic King Shag ( Leucocarbo carunculatus ) has occupied only a narrow portion of the northeastern South Island for at least the past 240 years. However, pre-human Holocene fossil and archaeological remains have suggested a far more widespread distribution of the three Leucocarbo species (King, Otago, Foveaux) on mainland New Zealand at the time of Polynesian settlement in the late 13th Century CE. We use modern and ancient DNA, and morphometric and osteological analyses, of modern King Shags and Holocene fossil Leucocarbo remains to assess the pre-human distribution and taxonomic status of the King Shag on mainland New Zealand, and the resultant conservation implications. Our analyses show that the King Shag was formerly widespread around southern coasts of the North Island and the northern parts of the South Island but experienced population and lineage extinctions, and range contraction, probably after Polynesian arrival. This history parallels range contractions of other New Zealand seabirds. Conservation management of the King Shag should take into account this species narrow distribution and probable reduced genetic diversity. Moreover, combined genetic, morphometric and osteological analyses of prehistoric material from mainland New Zealand suggest that the now extinct northern New Zealand Leucocarbo populations comprised a unique lineage. Although these distinctive populations were previously assigned to the King Shag (based on morphological similarities and geographic proximity to modern Leucocarbo populations), we herein describe them as a new species, the Kohatu Shag ( Leucocarbo septentrionalis ). The extinction of this species further highlights the dramatic impacts Polynesians and introduced predators had on New Zealand’s coastal and marine biodiversity. The prehistoric presence of at least four species of Leucocarbo shag on mainland NZ further highlights its status as a biodiversity hotspot for Phalacrocoracidae.

The Fluttering Shearwater (Puffinus gavia) is an abundant seabird endemic to breeding colonies in northern and central New Zealand. The species remains poorly studied, and here we present the first...

The Common Diving Petrel (Pelecanoides urinatrix) is an abundant seabird species within New Zealand waters. Breeding in this species occurs from late July through to December and adults are thought to remain in New Zealand waters during non-breeding months. Yet no studies of the spatial ecology of the species within New Zealand have been undertaken to confirm this. We used geolocation loggers with seawater immersion probes to characterise the year-round distribution and activity of P. urinatrix from two colonies (Kauwahaia Island and Burgess Island) in northern New Zealand. Adult birds exhibited extended pre-laying occupation of breeding sites (~95 days) and throughout breeding remained within 300 km of their colony. Burgess Island birds returned near nightly to their burrows throughout the breeding season. During non-breeding birds made a rapid and unpredicted migration south-east to the Antarctic polar front (covering 3000–5000 km in 3–13 days) and exhibited a dramatic shift in behaviour by spen...

We present the first study to examine the year-round distribution, activity patterns, and habitat use of one of New Zealand’s most common seabirds, the fluttering shearwater (Puffinus gavia). Seven adults from Burgess Island, in the Hauraki Gulf, and one individual from Long Island, in the Marlborough Sounds, were successfully tracked with combined light-saltwater immersion loggers for one to three years. Our tracking data confirms that fluttering shearwaters employ different overwintering dispersal strategies, where three out of eight individuals, for at least one of the three years when they were being tracked, crossed the Tasman Sea to forage over coastal waters along eastern Tasmania and southeastern Australia. Resident birds stayed confined to waters of northern and central New Zealand year-round. Although birds frequently foraged over pelagic shelf waters, the majority of tracking locations were found over shallow waters close to the coast. All birds foraged predominantly in daylight and frequently visited the colony at night throughout the year. We found no significant inter-seasonal differences in the activity patterns, or between migratory and resident individuals. Although further studies of inter-colony variation in different age groups will be necessary, this study presents novel insights into year-round distribution, activity patterns and habitat use of the fluttering shearwater, which provide valuable baseline information for conservation as well as for further ecological studies.

Genetic data are increasingly being used to prioritize species conservation in a fiscally constrained age of seemingly boundless conservation crises. Such data can also reveal previously cryptic biodiversity requiring further revision of conservation management guidelines. Using a combination of mitochondrial (control region) and nuclear (beta fibrinogen intron 7) DNA, and morphology, we reveal that the endemic New Zealand Spotted Shag (Phalacrocorax punctatus) complex exhibits phylogenetic structure that is decoupled from previously recorded qualitative morphological variation. Crucially, the most genetically distinct populations within P. punctatus are from northern New Zealand; recent surveys show that these populations, which house important genetic diversity within Spotted Shags, are in danger of being extirpated. In contrast, we find the previously phenotypically differentiated nominate (P. punctatus punctatus) and Blue (P. punctatus oliveri) Shag subspecies show no genetic and morphological separation, and are of least conservation concern.

Summary 1.Passive bioacoustic recording devices are now widely available and able to continuously record remotely located sites for extended periods, offering great potential for wildlife monitoring and management. Analysis of the huge datasets generated, in particular for specific biotic sound recognition, remains a critical bottleneck for widespread adoption of these technologies as current methods are labour intensive. 2.Several methods borrowed from speech processing frameworks, such as hidden Markov models, have been successful in analysing bioacoustic data but the software implementations can be expensive and difficult to use for non-specialists involved in wildlife conservation. To remedy this, we present a software interface to a popular speech recognition system making it possible for non-experts to implement hidden Markov models for bioacoustic signal processing. Octave/Matlab functions are used to simplify the set up and the definition of a bioacoustic signal recogniser as well as the analysis of the results. 3.We present the different functions as a workflow. To demonstrate how the package can be used we give the results of an analysis of a bioacoustic monitoring dataset to detect the nocturnal presence and behaviour of a cryptic seabird species, the common diving petrel Pelecanoides urinatrix urinatrix, from Northern New Zealand. 4.We show that the package matlabHTK can be used efficiently to reconstruct the daily patterns of colony activity in the common diving petrel. This article is protected by copyright. All rights reserved.

International audience; The distributions of migratory species in the ocean span local, national and international jurisdictions. Across these ecologically interconnected regions, migratory marine species interact with anthropogenic stressors throughout their lives. Migratory connectivity, the geographical linking of individuals and populations throughout their migratory cycles, influences how spatial and temporal dynamics of stressors affect migratory animals and scale up to influence population abundance, distribution and species persistence. Population declines of many migratory marine species have led to calls for connectivity knowledge, especially insights from animal tracking studies, to be more systematically and synthetically incorporated into decision-making. Inclusion of migratory connectivity in the design of conservation and management measures is critical to ensure they are appropriate for the level of risk associated with various degrees of connectivity. Three mechanisms exist to incorporate migratory connectivity into international marine policy which guides conservation implementation: site-selection criteria, network design criteria and policy recommendations. Here, we review the concept of migratory connectivity and its use in international policy, and describe the Migratory Connectivity in the Ocean system, a migratory connectivity evidence-base for the ocean. We propose that without such collaboration focused on migratory connectivity, efforts to effectively conserve these critical species across jurisdictions will have limited effect.

Identification of breeding sites remains a critical step in species conservation, particularly in procellariiform seabirds whose threat status is of global concern. We designed and conducted an integrative radiotelemetry approach to uncover the breeding grounds of the critically endangered New Zealand Storm Petrel Fregetta maoriana (NZSP), a species considered extinct before its rediscovery in 2003. Solar-powered automated radio receivers and hand-held telemetry were used to detect the presence of birds on three island groups in the Hauraki Gulf near Auckland, New Zealand. At least 11 NZSP captured and radiotagged at sea were detected at night near Te Hauturu-o-Toi/Little Barrier Island with the detection of an incubating bird leading to the discovery of the first known breeding site for this species. In total, four NZSP breeding burrows were detected under mature forest canopy and three adult NZSP and two NZSP chicks were ringed. Telemetry data indicated NZSP showed strong moonlight avoidance behaviour over the breeding site, had incubation shifts of approximately 5 days and had a breeding season extending from February to June/July, a different season from other Procellariiformes in the region. Radiotelemetry, in combination with rigorously collected field data on species distribution, offers a valuable technique for locating breeding grounds of procellariiform seabirds and gaining insights into breeding biology while minimizing disturbance to sensitive species or damage to fragile habitat. Our study suggests an avenue for other breeding ground searches in one of the most threatened avian Orders, and highlights the general need for information on the location of breeding sites and understanding the breeding biology in data-deficient birds.

In an effort to promote population recovery, translocations of the endemic Mottled Petrel (Pterodroma inexpectata) from remote offshore islands to the mainland are planned within New Zealand. To optimise these efforts we studied chick growth, adult provisioning and meal size for this species and report the results of a simulated translocation undertaken toassess how translocatedchicks, fed anartificial diet,performed incomparison withhandled andnon-handled controls that were provisioned by their parents. Our results found that wing-chord length and chick mass did not differ betweentranslocatedandcontrolchicks,withallchicks fledgingatapproximatelythesamemassandwingsizeranges.There was no difference in the timing of emergence from burrows before fledging between control and translocated chicks. The probability of a chick receiving a meal each night declined as chicks approached fledging and average meal size did not change as chicks approached fledging. From these data we now have the basis with which to make recommendations to increase thesuccess of future translocation efforts for Mottled Petrels. It isimportant toshare any knowledge of the biology and ecology of gadfly petrels, and any successes or failures in translocation practices in order to promote the best possible chance of future conservation of these species.

Within breath-hold diving endotherms, procellariiform seabirds present an intriguing anomaly as they regularly dive to depths not predicted by allometric models. How this is achieved is not known as even basic measures of physiological diving capacity have not been undertaken in this group. To remedy this we combined time depth recorder (TDR) measurements of dive behaviour with haematology and oxygen store estimates for 3 procellariiform species (common diving petrels Pelecanoides urinatrix urinatrix; grey-faced petrels Pterodroma macro ptera gouldi; and sooty shearwaters Puffinus griseus) during their incubation phase. Among species, we found distinct differences in dive depth (average and maximal), dive duration and dives h �1 , with sooty shearwaters diving deeper and for longer than grey-faced petrels and common diving petrels. Conversely, common diving petrels dove much more frequently, albeit to shallow depths, whereas grey-faced petrels rarely dived whatsoever. Such differences in dive behaviour were reflected in haematological parameters, with sooty shearwaters having higher red blood cell counts and haematocrit (Hct) values compared to common diving and grey-faced petrels; whereas common diving petrels had significantly lower Hct but possessed higher haemoglobin concentrations per cell and greater respiratory oxygen stores than both sooty shearwaters and grey-faced petrels. Such results provide the first insights into the physiological traits underpinning procellariiform dive behaviour, and confirm the trend for deep-diving seabirds to have proportionally lower blood and respiratory oxygen stores than shallow divers.

Following breeding, sooty shearwaters Puffinus griseus leave New Zealand waters and migrate to 1 of 3 distinct areas in the North Pacific Ocean, effectively exploiting environmen- tal resources across a large proportion of this northern ocean basin. In this study, we combined electronic tracking technology with stable isotope analyses (δ 15 N and δ 13 C) of feathers grown dur- ing the non-breeding period in order to evaluate whether isotope signatures can be used to iden- tify specific non-breeding areas used by sooty shearwaters. A region to the east of Japan was utilised by the majority of tracked birds, whereas others used areas off the west coast of North America. Stable isotope values of feathers allowed the discrimination of individuals that used each of the 3 different non-breeding areas, and suggested that birds off Japan can be further separated into 'coastal' and 'offshore' groups. Our results confirm the utility of using stable isotope analysis, validated by tracking devices, as a tool to determine distribution and habitat use of a long-range oceanic migrant, the sooty shearwater. These results also highlight the resource connectivity between the northern and southern Pacific Ocean basin.

Conservation of gadfly petrels, some of the most threatened seabirds, is frequently dependent on long-term research and management. We review 20 years of a program preventing the extinction of the Chatham petrel (Pterodroma axillaris), a New Zealand endemic once declining due to intense burrow competition from another native seabird. Breeding success in the early 1990s was unsustainably low (10–30%). Recovery measures started in 1992 when Chatham petrel burrows were converted and artificial entrances blockaded to exclude broad-billed prions (Pachyptila vittata). Pair and burrow fidelity were enhanced, though prions still posed a threat during Chatham petrel chick-rearing. Breeding success improved when prions were culled, however a less intensive and contentious solution was to introduce burrow flaps in 2001 which reduced interference from prospecting prions. Subsequently, breeding success increased to a mean 80% per annum. Finding burrows, primarily using radio-telemetry, increased those under management from eight in 1990 to 217 in 2010 when spotlight surveys indicated 72% of juvenile birds had fledged from managed burrows. Chick translocations to two other islands and increasing population size (from 200–400 birds in 1990 to an estimated 1400 birds by 2010) has improved the species IUCN status from Critically Endangered in 1990 to Endangered in 2013.

Handling of avian study species is common in ecological research, yet few studies account for the impact of handling in nestlings where exposure to stress may result in negative lifetime fitness consequences. As a result, our understanding of stress reactivity in free-living avian young is limited. In this study we examined the cumulative impact of three levels of research-relevant handling (control, daily and every three days) on the development of the stress response, growth and condition of semi-precocial seabird chicks from near-hatching to near-fledging. By measuring corticosterone concentrations in plasma, we found that mottled petrel (Pterodroma inexpectata) chicks were capable of mounting a stress response comparable to adults from near-hatching. There were no differences in plasma corticosterone concentrations in initial samples (

International audience; Niche divergence is expected for species that compete for shared resources, including migrants that occupy similar regions during the non-breeding season. Studies of temperate seabirds indicate that both spatial and behavioural segregation can be important mechanisms for reducing competition, but there have been few investigations of resource partitioning by closely related taxa in low productivity, tropical environments. We investigated niche partitioning in 3 gadfly petrel taxa, Pterodroma leucoptera leucoptera (n = 22), P. leucoptera caledonica (n = 7) and P. pycrofti (n = 12), during their non-breeding season in the eastern tropical Pacific Ocean by combining tracking data from geolocator-immersion loggers with remotely sensed environmental data in species distribution models (SDMs), and by comparing feather stable isotope ratios. The 3 taxa showed spatial partitioning: two foraged in the North Equatorial Counter Current and one in the South Equatorial Current. This reflected differences in their realised habitat niches, with significant taxon-specific responses to thermocline depth, sea surface temperature and bathymetry. There were also differences among taxa in activity patterns, and all birds spent a much larger proportion of time in flight at night than during the day, suggesting predominance of nocturnal foraging behaviour. Comparison of stable isotope ratios in feathers suggests that P. l. leucoptera and P. pycrofti mainly consume vertically migrating mesopelagic fishes, whereas the diet of P. l. caledonica also includes some lower trophic levels including crustaceans and squid. Unique insights can be gained from studies of the foraging ecology of tropical pelagic seabirds, in comparison with temperate and polar waters, and are urgently required for understanding and protecting tropical avifauna in key marine habitats.

Petrels are highly mobile seabirds that face many threats and whose conservation is frequently hampered by a lack of understanding of their biology at sea. We used a combination of data from burrow monitoring and geolocation-immersion loggers to study the intra- and inter-seasonal distribution and behaviour of the endangered Chatham Petrel (Pterodroma axillaris), breeding on Rangatira Island, New Zealand. Breeding extended from November to June with a pre-laying exodus of 35 days; an incubation period of 46 days, with up to five incubation shifts; and a chick-rearing period of 87 days, including a desertion period of 10 days. When breeding, Chatham Petrels foraged between the Subtropical Convergence and Subantarctic Fronts, moving 2000–3000 km to the south-east of the Chatham Islands, during the pre-laying exodus and incubation period, but restricting foraging to the south of the Chatham Islands, around the Bollons Seamount, during chick-rearing. Between April and June birds migrated east and north to core non-breeding distributions ~1000 km from the coast of Peru and Chile. Birds spent a greater proportion of time resting and nocturnally active during the non-breeding period than when breeding, when birds where active during darkness and daylight. These data contribute to the conservation management of the Chatham Petrel and to conservation initiatives to identity marine protected areas for endangered seabirds on the high seas beyond national jurisdictions.

The flesh-footed shearwater Puffinus carneipes is a medium-sized shearwater and transequatorial migrant within the Pacific Ocean. We used archival data loggers to study the non-breeding migration and diving behaviour of three flesh-footed shearwaters following breeding in New Zealand. In early April, the birds migrated to the western North Pacific Ocean in 23±2 days, occupying core distributions within the Kuroshio/Oyashio transition system for 91±17 days. Subsequent movements were made into the Sea of Okhotsk prior to return migrations to New Zealand in mid September (19±1 days). Diving depths during migration (2.5±2.4 m), and in the western North Pacific (2.4±2.6 m) were shallower than during the onset of breeding (4.8±8.7 m). Non-breeding flesh-footed shearwaters occupy a region of high fisheries activity and the impact of these fisheries on adult survival in this declining species warrant further study.

The long breeding period and high reproductive investment of seabirds make use of resource-rich foraging areas pivotal both during and between breeding seasons. We tracked adult Australasian Gannets (Morus serrator) from their New Zealand breeding colony at Cape Kidnappers to Australia during the non-breeding period to assess wintering behavior and migratory routes for this species. Data from three recovered geolocation sensor (GLS) tags showed that both a male and a female M. serrator, and a hybrid M. capensis × M. serrator migrated across the Tasman Sea to winter in Australian and Tasmanian coastal waters. Tracked birds covered distances of up to 13,000 km on their migration. These movements were consistent with historical records of band recoveries.

Knowledge of the dynamics of long-distance migrations of pelagic seabirds is limited. Recent advances in tracking technology have yielded detailed, continuous accounts of the movements of individual seabirds over large spatial and temporal scales. We studied the timing of migration and year-round distribution of the Westland Petrel (Procellaria westlandica), listed by the IUCN as vulnerable, with miniature archival light loggers (geolocators) deployed on 10 incubating birds breeding in 2007 at Westland, New Zealand. We retrieved data from eight Westland Petrels, indicating the birds migrated in November directly east ∼7000 km from the coast of New Zealand to South American waters in 6 days (range 4–7), then returned the following April in 10 days (range 8–13). The durations of an individual's outward and return flights and the dates of its outward and return migrations were positively correlated. During their journeys east and west, birds spent on average (±SD) 9.9% (±9.7) and 17.2% (±12.0), res...

The endangered Cook’s petrel (Pterodroma cookii) is restricted to two separated populations at the extremes of its former range across New Zealand. Prior work revealed morphological, foraging, and reproductive isolation between these two remnant populations. To aid the conservation management of the species, additional information is required on the genetic structure of Cook’s petrel. We used mitochondrial DNA sequences (Cytochrome Oxidase subunit 1 gene), collected from 26 and 19 Cook’s petrel breeding on Little Barrier Island (LBI) and Codfish Island (CDF), respectively, for this preliminary study. We uncovered distinct population genetic structure with analysis of molecular variance suggesting genetic isolation of the populations. Levels of genetic variation were higher in the LBI population (four haplotypes present; h = 0.34 and π = 0.10) whereas the CDF population had only one haplotype that was distinct from the LBI population. Our results indicate that Cook’s petrel constitute two distinct management units for which conservation of genetic as well as behavioural and morphological diversity should be a priority. Further genetic studies using nuclear markers are recommended.

A variety of bioacoustics distance metrics have been used to assess similarities in the vocalizations of different individuals. Here, we provide a detailed analysis of several acoustic similarity indices, some of which have been developed with the specific aim of characterizing the sensory coding of auditory stimuli. We compare different approaches through the analysis of begging calls of several passerine species and specialist brood parasitic cuckoos that putatively evolved to mimic their hosts. The different bioacoustics distances did not provide consistently corre- lated similarity patterns, implying that they are sensitive to different sound features. However, the encoded spectro- gram alignment method was correlated with all other acoustic distance metrics, suggesting that this method

Pelagic seabirds are central place foragers during breeding and variation in foraging trip duration and range reflect differences in diet and chick provisioning, through the exploitation of divergent habitats of varying productivity. We tested whether these relationships hold in small procellarriids by equipping chick-rearing Cook’s petrel Pterodroma cookii (200 g) with geolocation-immersion loggers, conducting isotope analysis of blood and measuring chick meal mass following foraging trips of varying duration. Cook’s petrel tracked during chick rearing from Little Barrier Island (LBI) and Codfish Island (CDF), New Zealand had larger maximum ranges during longer foraging trips. Blood nitrogen isotope signatures (δ15N) of adults were significantly higher after foraging trips of longer duration, but not of greater maximum range. There was no significant relationship between blood carbon isotope signatures (δ13C) and foraging trip characteristics. Proportion of time spent on the sea surface and the mass of the meal brought back to chicks were consistently greater for Cook’s petrel with larger maximum ranges, which in the case of birds from CDF coincided with productive subtropical convergence zone habitats. As predicted, trip duration reflected divergent foraging behaviours in Cook’s petrel during breeding. We suggest that the availability of different prey is a key factor governing at-sea distributions and dietary composition of this species.

SummaryCodfish Island is the southernmost breeding location for Cook's Petrel (Pterodroma cookii), endemic to the New Zealand archipelago. To provide a population estimate and indication of population growth following introduced predator eradications we conducted an island-wide survey of Codfish Island within two a priori defined strata. Plot surveys revealed only five burrows within forest habitats from 175 plots surveyed and the locations of these and other burrows observed incidentally were used to identify three key areas of Cook's Petrel breeding activity that were subsequently surveyed using line transects. Within these areas, 42 burrows were counted with burrow densities ranging from 0.0003 to 0.002 burrows m−2. Burrow densities in conjunction with the three-dimensional surface areas of the surveyed locations suggested a minimum of 6,194 ± 956 burrows present and equated to approximately 5,000 (95% CI 3,000–6,000) breeding pairs, using a burrow occupancy estimate of 80%. The Cook's Petrel population on Codfish Island appears to have increased markedly since Weka (Gallirallis australis ) and Pacific Rat (Rattus exulans) were eradicated in 1980 and 1998 and is consistent with a recent upwards revision of the species' world population size of approximately 1,300,000 (900,000–1,800,000) individuals. Revised population data, and ongoing protection of Cook's Petrel's major breeding sites may now qualify the species for a revised conservation status moving from Endangered to Vulnerable under IUCN criteria.

Inaccurate population data remain a major problem in the conservation of burrow-nesting Procellariiform seabirds. We evaluated the potential of predictive habitat modelling, in contrast with traditional surface-area based strategies, to estimate the population size of the endangered Cook’s petrel ( Pterodroma cookii ), breeding on one of two islands in New Zealand. Generalised linear models of burrow abundance using topographic data collected in the field, or extracted from Geographic Information System layers, were developed, and the final model applied to Geographic Information Systems-derived datasets in a population analysis. To compare this result with traditional census methods, population estimates were also calculated by averaging burrow densities across the total area available (simple model) and within vegetation zones (habitat-area model). Results of all models were scaled using rigorously collected burrow occupancy data. The final model, based upon altitude, slope, and distance from ridgelines, explained 31% of the variance in Cook’s petrel burrow abundance and showed an enhanced predictive fit compared with the two area-based models. This model indicated that annually 286,000 (95% confidence interval: 213,000–413,000) pairs of Cook’s petrel breed on Little Barrier Island, approximately six times that previously suggested. Population estimates based on simple and habitat-area models were less accurate, being 10% and 30% greater than the predictive model estimate, respectively. This study underlines the need for accurate population estimates for burrowing seabird taxa by presenting a major population revision for the Cook’s petrel. Predictive habitat models, employing rigorously collected data, offer an improvement on more traditional population census methodologies that are susceptible to scale-induced bias.

Cook’s Petrel (Pterodroma cookii), a trans-equatorial migrant endemic to the New Zealand archipelago, is today endangered and restricted to island habitats at the northern and southern extents of its former range. To improve the limited knowledge of the breeding habitat of this species, we combined an island-wide survey, the mapping capabilities of geographic information systems, and logistic and autologistic analyses to examine burrow distribution and habitat use of the world’s largest population of Cook’s Petrel, on Little Barrier Island (Hauturu). Our results show that, on this island, Cook’s Petrel breeds predominantly above 300 m above sea level, on steeper slopes, closer to ridge tops, and in unmodified forest habitats with low and open canopies and greater numbers of large stems compared to the available terrain and habitat. Within these habitats above 300 m, densities of burrows are 0.04 burrows m–2. Through comparisons with habitat data from two low-altitude colonies, we conclude that the current distribution of this population is a result of habitat selection and historical human-mediated impacts. We suggest that mature forest habitats, close proximity to ridge tops, and steep slopes are key habitat requirements for this species. A large amount of suitable habitat is available for Cook’s Petrel on Little Barrier Island and the recent removal of introduced predators is expected to result in an expansion of this population. The results of the current study provide useful information to aid in the restoration of former colony sites on other islands and the New Zealand mainland.

International audience; This study describes and compares the pelagic distribution and migratory patterns of the two subspecies ofGould’s Petrel (Pterodroma leucoptera), and contrasts data obtained from tracking birds at sea using geolocators withobservational data (shipboard sightings, by-catch records and beachcast specimens). While breeding, tracked individuals ofboth subspecies (P. l. leucoptera and P. l. caledonica) foraged within the Tasman Sea and south of the Australian continent,with forays west into the Indian Ocean before laying. After breeding, both subspecies migrated to distinct non-breedingranges within the eastern tropical Pacific Ocean. Observational data identified the general pattern of migration and foragingareas of the species, whereas data from geolocators provided details of routes and timing of migration, core foraging ranges,and marked spatial and temporal segregation between the two subspecies. However, by attaching geolocators only toestablished breeders, as is typical of studies of small and medium-sized seabirds, these devices failed to identify that nonbreedingbirds (pre-breeders and adults that are deferring breeding) may not follow the same migratory schedules or have thesame at-sea distribution. We conclude that integrating data from electronic tracking with observational data substantiallyimproves our understanding of the pelagic distribution of seabird populations.

The effect of 4.5-g dummy geolocation loggers on the foraging ability of Cook's Petrel (Pterodroma cookii) was assessed over single foraging trips from Little Barrier Island, New Zealand. I compared foraging trip duration and chick provisioning between equipped and unequipped birds and could not detect a detrimental effect of loggers on either parameter. The lack of effect of these loggers may be the result of their small size, the short-term nature of their use, and foraging strategies used by Cook's Petrel. Geolocation studies involving Cook's Petrel and other small gadfly petrel species may be feasible for single foraging trips.

Pelagic seabirds are highly mobile, reducing the likelihood of allopatric speciation where disruption of gene flow between populations is caused by physically insurmountable, extrinsic barriers. Spatial segregation during the non-breeding season appears to provide an intrinsic barrier to gene flow among seabird populations that otherwise occupy nearby or overlapping regions during breeding, but how this is achieved remains unclear. Here we show that the two genetically distinct populations of Cook's petrel (Pterodroma cookii) exhibit transequatorial separation of non-breeding ranges at contemporary (ca. 2-3 yrs) and historical (ca. 100 yrs) time scales. Segregation during the non-breeding season per se appears as an unlikely barrier to gene flow. Instead we provide evidence that habitat specialization during the non-breeding season is associated with breeding asynchrony which, in conjunction with philopatry, restricts gene flow. Habitat specialization during breeding and non-breeding likely promotes evolutionary divergence between these two populations via local adaptation.

Predator–prey communities are ubiquitous in ecology, but introduced predators can drive native species to extinction within island systems, prompting the eradication of such exotics. Ecological theory predicts that elimination of top-introduced predators from islands can lead to the counterintuitive decline of native prey populations through the ecological release of smaller introduced species in a process termed “mesopredator release.” We show, in accordance with mesopredator release theory and counter to conservation goals for a New Zealand island reserve, that initial eradication of cats on Little Barrier Island led to reduced breeding success of Cook's petrels, which also are vulnerable to predation by a mesopredator, the Pacific rat. The rat's impact on prey productivity varied with elevation within the island. Rat eradication was followed by a rise in petrel productivity, in support of both ecological theory and practical conservation management goals. It appears that interactions among introduced predators, native prey, and environmental gradients can drive counterintuitive and spatially heterogeneous responses to predator eradications from islands. Location-specific, ecosystem-level understanding is essential for predicting the outcomes of such restoration management techniques.

The influence of the Earth's magnetic field on locomotory orientation has been studied in many taxa but is best understood for homing pigeons (Columba livia). Effects of experimentally induced and naturally occurring perturbations in the geomagnetic field suggest that pigeons are sensitive to changes in geomagnetic parameters. However, whether pigeons use the Earth's magnetic field for position determination remains unknown. Here we report an apparent orientation to theintensitygradient of the geomagnetic field observed in pigeons homing from sites in and around a magnetic anomaly. From flight trajectories recorded by GPS-based tracking devices, we noted that many pigeons released at unfamiliar sites initially flew, in some cases up to several kilometres, in directions parallel and/or perpendicular to the bearing of the local intensity field. This behaviour occurred irrespective of the homeward direction and significantly more often than what was expected by random chance. Our study describes a novel behaviour which provides strong evidence that pigeons when homing detect and respond to spatial variation in the Earth's magnetic field—information of potential use for navigation.