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1. Light-level geolocators are popular bio-logging tools, with advantageous sizes, longevity and affordability. Biologists tracking seabirds often presume geolocator spatial accuracies between 186 and 202 km from previously innovative, yet taxonomically, spatially and computationally limited, studies. Using recently developed methods, we investigated whether assumed uncertainty norms held across a larger-scale, multispecies study.2. We field-tested geolocator spatial accuracy by synchronously deploying these with GPS loggers on scores of seabirds across five species and 11 Mediterranean Sea, east Atlantic and south Pacific breeding colonies. We first interpolated geolocations using the geolocation package FLightR without prior knowledge of GPS tracked routes. We likewise applied another package, probGLS, additionally testing whether sea-surface temperatures could improve route accuracy.3. Geolocator spatial accuracy was lower than the ~200 km often assumed. prob-GLS produced the best accuracy (mean ± SD = 304 ± 413 km, n = 185 deployments) with 84.5% of GPS-derived latitudes and 88.8% of longitudes falling within resulting uncertainty estimates. FLightR produced lower spatial accuracy (408 ± 473 km, n = 171 deployments) with 38.6% of GPS-derived latitudes and 23.7% of longitudes within package-specific uncertainty estimates. Expected inter-twilight period (from GPS position and date) was the strongest predictor of accuracy, with increasingly equatorial solar profiles (i.e. closer temporally to equinoxes and/or spatially to the Equator) inducing more error. Individuals, species and geolocator model also significantly affected accuracy, while the impact of distance travelled between successive twilights depended on the geolocation package.4. Geolocation accuracy is not uniform among seabird species and can be considerably lower than assumed. Individual idiosyncrasies and spatiotemporal dynamics

Long-distance movements are characteristic of most seabirds in the order Procellariiformes. However, little is known about the migration and foraging ranges of many of the smaller species in this order, especially storm-petrels (Hydrobatidae). We used Global Location Sensors to document the year-round movements of sympatrically breeding Fork-tailed Storm-Petrels (Oceanodroma furcata) and Leach's Storm-Petrels (O. leucorhoa) from the Gillam Islands located northwest of Vancouver Island, British Columbia, Canada. In 2016, breeding Fork-tailed (N = 5) and Leach's (N = 2) storm-petrels traveled maximum distances of~1550-1600 km from their colony to a region that has a wide shelf with major canyons creating a highly productive foraging area. After the breeding season, Fork-tailed Storm-Petrels (N = 2) traveled to similar areas west of the Gillam Islands, a maximum distance of~3600 km from the breeding colony, and remained in the North Pacific Ocean and north of the Subarctic Boundary for an average of 5.4 mo. Postbreeding Leach's Storm-Petrels (N = 2) moved south to the Eastern Tropical Pacific, west of central Mexico, Ecuador, and northern Peru, an estimated maximum distance of~6700 km from their breeding colony, and remained there for an average of 7.2 mo. Carbon (d 13 C) and nitrogen (d 15 N) stable isotope analyses of feathers revealed niche separation between Fork-tailed (N = 21) and Leach's (N = 53) storm-petrels. The wide range of d 15 N values in the feathers of Leach's Storm-Petrels (N = 53) suggests that they foraged at a variety of trophic levels during the non-breeding season. Our results demonstrate that storm-petrels have large core foraging areas and occupy vast oceanic areas in the Pacific during their annual cycle. However, given the coarse precision of Global Location Sensors, additional study is needed to identify the specific areas used by each species during both breeding and non-breeding periods.RESUMEN. Movimientos anuales de los simp atricos Pa ıño rabihorcado (Oceanodroma furcata) y Pa ıño boreal (O. leucorhoa) Los moviemientos a larga distancia son caracter ısticos de la mayor ıa de las aves marinas del orden Procellariiformes. Aun as ı, poco se sabe de la migraci on y los rangos de forrajeo de las especies m as pequeñas del orden, especialmente los petreles de las tormentas o pa ıños (Hydrobatidae). Usamos Sensores de Ubicaci on Global para documentar los movimientos durante todo el año de dos especies que cr ıan simp atricamente, el Pa ıño rabihorcado (Oceanodroma furcata) y el Pa ıño boreal (O. leucorhoa), desde las Islas Gillam ubicadas al noroeste de la Isla de Vancouver, Columbia Brit anica, Canad a. En 2016, los pa ıños rabihorcados (N = 5) y boreales (N = 2) reproductivamente activos viajaron distancias m aximas de~1550-1600 km desde su colonia a una regi on que tiene una placa ancha con grandes cañones que crean un area de forrajeo altamente productiva. Luego de la temporada reproductiva, los pa ıño rabihorcados (N = 2) viajaron a areas similares al oeste de las Islas Gillam, una dis...

Background: Common bottlenose dolphins (Tursiops truncatus) are distributed globally in tropical and warmtemperate waters with coastal and offshore ecotypes known. In the eastern North Pacific Ocean, common bottlenose dolphins are typically found in offshore waters as far as 41°N and in coastal waters as far as 38°N. Despite considerable survey effort, the species has not been previously recorded in Canadian Pacific waters. Results: On 29 July 2017, a group of approximately 200 common bottlenose dolphins were observed together with approximately 70 false killer whales (Pseudorca crassidens) in waters of 16.5°C at 50°N during a pelagic seabird and marine mammal survey off the west coast of northern Vancouver Island, British Columbia, Canada. Conclusions: This sighting represents the only occurrence of common bottlenose dolphins recorded in Canadian Pacific waters and, to our knowledge, is the most northerly record for this species in the eastern North Pacific. It is also the first sighting record of false killer whales in non-coastal waters in British Columbia, Canada. The occurrence of both species may be associated with a prolonged period of warming in offshore regions of the eastern North Pacific.

Gadfly petrels (genus Pterodroma) are one of the most threatened groups of birds. They are exceptionally well adapted to forage over enormous areas to maximize chances of encountering prey. Their wide-ranging travel, extensive use of oceanic habitats beyond national jurisdictions (the high seas), and limited information on their at-sea distributions and foraging ecology pose several management challenges. Here, we examined the foraging distributions and habitat preferences of three gadfly petrels that breed on Phillip Island (Norfolk Island Group), in the southwest Pacific Ocean, and tested the ability of species distribution models (SDMs) to predict important marine habitats. GPS loggers were deployed in 2018 and 2019 on chick-provisioning black-winged petrels (P. nigripennis) and white-necked petrels (P. cervicalis) and in 2020 on Kermadec petrels (P. neglecta), and hidden Markov models (HMMs) were used to estimate behavioral states across 387 foraging trips. SDMs were built using six algorithms and the predictive performance of models constructed using conventional random cross-validation (CV) was compared to those constructed with spatially independent CV. All three species demonstrated dual-foraging strategies with short trips closer to the colony and longer, presumably self-provisioning, trips with maximum distances from the colony of several thousand kilometers for black-winged and white-necked petrels. Foraging areas of each species were distinctly partitioned across the Tasman Sea during long trips, but there was high overlap during short trips. Black-winged and white-necked petrels exhibited area-restricted search foraging behavior throughout their foraging ranges which spanned almost the entire Tasman Sea and into the western Pacific, whereas the foraging range of Kermadec petrels was restricted closer to the colony. Approximately half of each species’ foraging range extended into the high seas. Response curves and variable importance between the two SDM CV approaches were similar, suggesting that model fitting was robust to the CV approach. However, evaluation using spatially independent CV indicated that generalizability of ensemble SDMs to new data ranged from poor to fair for all three species. This suggests that the maximal-area foraging strategy of gadfly petrels (whereby they search opportunistically for resources across expansive oceanic habitats) results in weak or wide associations with environmental features making predicting important habitats extremely challenging.

On isolated islands, large arthropods can play an important functional role in ecosystem dynamics. On the Norfolk Islands group, South Pacific, we monitored the diet and foraging activity of an endemic chilopod, the Phillip Island centipede (Cormocephalus coynei), and used a stable isotope mixing model to estimate dietary proportions. Phillip Island centipede diet is represented by vertebrate animals (48%) and invertebrates (52%), with 30.5% consisting of squamates, including the Lord Howe Island skink (Oligosoma lichenigera) and Günther's island gecko (Christinus guentheri); 7.9% consisting of black-winged petrel (Pterodroma nigripennis) nestlings; and 9.6% consisting of marine fishes scavenged from regurgitated seabird meals. Centipede predation was the principal source of petrel nestling mortality, with annual rates of predation varying between 11.1% and 19.6% of nestlings. This means that 2,109-3,724 black-winged petrel nestlings may be predated by centipedes annually. Petrels produce a single offspring per year; therefore, predation of nestlings by centipedes represents total breeding failure for a pair in a given year. Our work demonstrates that arthropods can play a leading role in influencing vertebrate reproductive output and modifying trophic structures and nutrient flow in island ecosystems.

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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.