Rachael A Orben

Oregon State University | OSU · Department of Fisheries Wildlife and Conservation Sciences

The Patagonian Shelf Large Marine Ecosystem supports high levels of biodiversity and endemism and is one of the most productive marine ecosystems in the world. Despite the important role marine predators play in structuring ecosystems, areas of high diversity where multiple predators congregate remains poorly known on the Patagonian Shelf. Here, we...

Background Inertial measurement units (IMUs) with high-resolution sensors such as accelerometers are now used extensively to study fine-scale behavior in a wide range of marine and terrestrial animals. Robust and practical methods are required for the computationally-demanding analysis of the resulting large datasets, particularly for automating cl...

Understanding encounters between marine predators and fisheries across national borders and outside national jurisdictions offers new perspectives on unwanted interactions to inform ocean management and predator conservation. Although seabird–fisheries overlap has been documented at many scales, remote identification of vessel encounters has lagged...

The Cormorant Oceanography Project is using sensors deployed on diving marine birds to collect broadly distributed oceanographic data in coastal regions around the world.

Static (fixed‐boundary) protected areas are key ocean conservation strategies, and marine higher predator distribution data can play a leading role toward identifying areas for conservation action. The Falkland Islands are a globally significant site for colonial breeding marine higher predators (i.e., seabirds and pinnipeds). However, overlap betw...

Seasonal variation in food availability or adverse weather patterns can create challenging conditions for year-round survival. Birds experiencing such fluctuations may migrate to locations with better food availability in the non-breeding period. While some species are obligate migrants, others are facultative migrants where various post-breeding s...

Estimates of movement costs are essential for understanding energetic and life-history trade-offs. Although overall dynamic body acceleration (ODBA) derived from accelerometer data is widely used as a proxy for energy expenditure (EE) in free-ranging animals, its utility has not been tested in species that predominately use body rotations or exploi...

Animal movement and population connectivity are key areas of uncertainty in efforts to understand and predict the spread of infectious disease. The emergence of highly pathogenic avian influenza (HPAI) in South America poses a significant threat to globally significant populations of colonial breeding marine predators in the South Atlantic. Yet, th...

Oceanographers face the lack of in-situ environmental data to investigate marine features' changes, particularly in some habitats or inaccessible areas. Collecting measurements on marine environments can be challenging and limited with traditional methods. This study shows the utilization of diving marine bird telemetry as an innovative method for...

2022 marked the third consecutive La Niña and extended the longest consecutive stretch of negative Oceanic Niño Index since 1998-2001. While physical and biological conditions in winter and spring largely adhered to prior La Niña conditions, summer and fall were very different. Similar to past La Niña events, in winter and spring coastal upwelling...

2022 marked the third consecutive La Niña and extended the longest consecutive stretch of negative Oceanic Niño Index since 1998-2001. While physical and biological conditions in winter and spring largely adhered to prior La Niña conditions, summer and fall were very different. Similar to past La Niña events, in winter and spring coastal upwelling...

We document the first visual observation of a Lasiurus cinereus (Hoary Bat) flying over the open ocean, 49 km from the northern California coast. This observation provides further evidence that this migratory species at times utilizes offshore habitat. Hoary Bats face significant, population level threats from collisions with onshore wind turbines,...

Animal movement and population connectivity are key areas of uncertainty in efforts to understand and predict the spread of infectious disease. The emergence of highly pathogenic avian influenza (HPAI) in South America poses a significant threat to globally significant populations of colonial breeding marine predators in the South Atlantic. Yet, th...

In 2013 and 2014, multiple field excursions of varying scope were concentrated on the Columbia River, a highly energetic, partially-mixed estuary. These experiments included surface drifter and Synthetic Aperture Radar (SAR) measurements during the ONR RIVET-II experiment, and a novel animal tracking effort that samples oceanographic data by employ...

Animal tracking has afforded insights into patterns of space use in numerous species and thereby informed area-based conservation planning. A crucial consideration when estimating spatial distributions from tracking data is whether the sample of tracked animals is representative of the wider population. However, it may also be important to track an...

Compared to other animal movements, prospecting by adult individuals for a future breeding site is commonly overlooked. Prospecting influences the decision of where to breed and has consequences on fitness and lifetime reproductive success. By analysing movements of 31 satellite-and GPS-tracked gull and tern populations belonging to 14 species in E...

Pelagic seabirds cover large distances efficiently and thus may reach a variety of marine habitats during breeding. Previous studies using stable isotope data and geolocators suggested that Thin-billed Prions breeding in the Falkland Islands in the Southwest Atlantic may forage in temperate waters over the Patagonian Shelf or cross the Drake Passag...

In late 2020, models predicted that a strong La Niña would take place for the first time since 2013, and we assessed whether physical and biological indicators in 2021 were similar to past La Niñas in the California Current Ecosystem (CCE). The Pacific Decadal Oscillation and Oceanic Niño Index indeed remained negative throughout 2021; the North Pa...

To forage optimally, predators face complex decisions regarding target prey distribution, quantity, and quality. We paired theodolite tracking of gray whales Eschrichtius robustus in Port Orford, Oregon, USA, with concurrent sampling of their zooplankton prey to examine foraging decisions relative to prey quantity (abundance) and quality (caloric c...

Marine protected areas (MPAs), particularly large MPAs, are increasing in number and size around the globe in part to facilitate the conservation of marine megafauna under the assumption that large-scale MPAs better align with vagile life histories; however, this alignment is not well established. Using a global tracking dataset from 36 species acr...

Since the last Arctic Monitoring and Assessment Programme (AMAP) effort to review biological effects of mercury (Hg) on Arctic biota in 2011 and 2018, there has been a considerable number of new Arctic bird studies. This review article provides contemporary Hg exposure and potential health risk for 36 Arctic seabird and shorebird species, represent...

Few studies have assessed the influence of data quality on the predicted probability of occurrence and preferred habitat of marine predators. We compared results from four species distribution models (SDMs) for four southern-hemisphere albatross species, Buller’s (Thalassarche bulleri), Campbell (T. impavida), grey-headed (T. chrysostoma), and whit...

Copies of this report are available from: Pacific Islands Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 1845 Wasp Boulevard, Building #176, Honolulu, Hawaii 96818 Or online at: https://repository.library.noaa.gov/ DOI: https://doi.org/10.25923/nb95-gs31

• The use of miniaturized electronic tracking devices has illuminated our understanding of seabird distributions and habitat use, and how anthropogenic threats interact with seabirds in both space and time. To determine the year-round distribution of adult Campbell albatross (Thalassarche impavida), a single-island endemic, breeding only at Campbel...

The California Current System (CCS) has experienced large fluctuations in environmental conditions in recent years that have dramatically affected the biological community. Here we synthesize remotely sensed, hydrographic, and biological survey data from throughout the CCS in 2019–2020 to evaluate how recent changes in environmental conditions have...

Knowledge of non-breeding distributions is a crucial component to seabird conservation, as conditions during the non-breeding period can play an important role in regulating seabird populations. Specifically, if seabirds from different colonies share the same wintering grounds, conditions in that shared region could have a widespread impact on mult...

Methylmercury concentrations vary widely across geographic space and among habitat types, with marine and aquatic-feeding organisms typically exhibiting higher mercury concentrations than terrestrial-feeding organisms. However, there are few model organisms to directly compare mercury concentrations as a result of foraging in marine, estuarine, or...

https://arctox.cnrs.fr/en/home/ Mercury (Hg) is a natural trace element found in high concentrations in top predators, including Arctic seabirds. Most current knowledge about Hg concentrations in Arctic seabirds relates to exposure during the summer breeding period when researchers can easily access seabirds at colonies. However, the few studies f...

1. Understanding encounters between marine predators and fisheries across national borders and outside national jurisdictions offers new perspectives on un-wanted interactions to inform ocean management and predator conservation. Although seabird-fisheries overlap has been documented at many scales, remote identification of vessel encounters has la...

Understanding the environmental and behavioral factors that influence how organisms maintain energy balance can inform us about their potential resiliency to rapid environmental changes. Flexibility in maintaining energy balance is particularly important to long-lived, central-place foraging seabirds that are constrained when locating food for offs...

Although many penguin species migrate during the non-breeding period, Gentoo Pen- guins Pygoscelis papua are year-round residents. Despite being characterized as inshore feeders, the at-sea spatial usage of Gentoo Penguins during the non-breeding period, when central place foraging constraints are relaxed, is poorly understood. Here, we tracked the...

Natural selection should favour strategies that maximise reproductive success. Females may use different resources during progressive stages of reproduction according to energetic demands, behavioural constraints and prey availability. We used South American fur seal, Arctocephalus australis australis, pup whisker isotope values as proxies for mate...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Marine methylmercury concentrations vary geographically and with depth, exposing organisms to different mercury levels in different habitats. Red-legged kittiwakes (Rissa brevirostris), a specialist predator, forage on fish and invertebrates from the mesopelagic zone, a part of the ocean with elevated methylmercury concentrations. We used kittiwake...

Avian species host diverse communities of microorganisms which have important roles in the life of birds, including increased metabolism, protection from disease, and immune system development. Along with high human populations and a diversity of human uses of coastal zones, anthropogenic food sources are becoming increasingly available to some spe...

Successful foraging of marine predators depends on environmental conditions, which also influence prey availability. Neutral or negative El Niño Southern Oscillation and Pacific Decadal Oscillation ocean conditions during the summer of 2013 and strongly positive conditions during the summer of 2015 in the northern California Current System provided...

South American fur seals ( Arctocephalus australis ) are widely distributed, yet surprisingly little is known about their ecology. In particular, population data are sparse and outdated for many breeding locations, including the Falkland Islands. Data deficiency impedes the development of coherent conservation and management strategies. To address...

Seabirds are integral components of marine ecosystems and, with many populations globally threatened, there is a critical need for effective and scalable seabird monitoring strategies. Many seabird species nest in burrows, which can make traditional monitoring methods costly, infeasible, or damaging to nesting habitats. Traditional burrow occupancy...

The California Current Ecosystem (CCE) has been in a primarily warm state since 2014, and this pattern largely continued into 2019. The CCE experienced a mild El Niño from late 2018 into 2019, and basin-scale indicators reflected this condition (elevated Oceanic Niño Index and Pacific Decadal Oscillation; Table 1). Despite the El Niño, spring upwel...

The implicit assumption of many ecological studies is that animal behaviour and resource use is geographically uniform. However, central place foraging species often have geographically isolated breeding colonies that are associated with markedly different habitats. South American fur seals (Arctocephalus australis) (SAFS) are an abundant and widel...

Specialization can make animals vulnerable to rapid environmental changes. For longlived seabirds, foraging specialization may make individuals especially sensitive, as climatic changes are currently occurring over the course of one lifetime. The Bering Sea is a dynamic subarctic and arctic ecosystem where windblown sea ice mediates annual producti...

ABSTRACT: The ability of juveniles of wide-ranging species to locate distant foraging regions can rely on innate or learned information. Reliance on innate cues could be problematic when conser- vation actions facilitate reintroduction. In the North Pacific, the short-tailed albatross Phoebastria albatrus is recovering from extensive harvesting, an...

Conditions experienced during the nonbreeding period have profound long-term effects on individual fitness and survival. Therefore, knowledge of habitat use during the non- breeding period can provide insights into processes that regulate populations. At the Falkland Islands, the habitat use of South American sea lions (Otaria flavescens) during th...

Identification and classification of behavior states in animal movement data can be complex, temporally biased, time-intensive, scale-dependent, and unstandardized across studies and taxa. Large movement datasets are increasingly common and there is a need for efficient methods of data exploration that adjust to the individual variability of each t...

Temporal sub-sampling of gray-headed albatross GPS tracks using Residence in Space and Time (RST) method. (DOCX)

Zip file containing R code, documentation and example dataset for running Residence in Space and Time (RST) method. (ZIP)

Probability of equal residual value resulting from different combinations of Residence Distance (RD) and Residence Time (RT). (DOCX)

Connecting the life history stages of the annual cycle via carry-over effects crucially informs estimates of mortality and reproduction. This study explores variables linking the breeding and wintering seasons in a pursuit-diving seabird, the thick-billed murre Uria lomvia. We deployed GLS loggers on chick-rearing murres breeding in the south-easte...

Identification and classification of behavior states in animal movement data can be complex, temporally biased, time-intensive, scale-dependent, and unstandardized across studies and taxa. Large movement datasets are increasingly common and there is a need for efficient methods of data exploration that adjust to the individual variability of each t...

Identification and classification of behavior states in animal movement data can be complex, temporally biased, time-intensive, scale-dependent, and unstandardized across studies and taxa. Large movement datasets are increasingly common and there is a need for efficient methods of data exploration that adjust to the individual variability of each t...

Uncertainty plots derived from the model-based clustering of southern sea lion pup stable isotopes, implemented within the R Package ‘Mclust’. The ellipses shown represent each cluster, with the smallest grey dots representing the lowest uncertainty and large black dots, the largest uncertainty (quantiles are 0.75,0.95 –the default quantiles used i...

Isotope data for 65 southern sea lion pups sampled from breeding colonies around the Falkland Islands (see ‘Methods’ for details). (DOCX)

Individuals within populations often differ substantially in habitat use, the ecological consequences of which can be far reaching. Stable isotope analysis provides a convenient and often cost effective means of indirectly assessing the habitat use of individuals that can yield valuable insights into the spatiotemporal distribution of foraging spec...

Our understanding of how air-breathing marine predators cope with environmental variability is limited by our inadequate knowledge of their ecological and physiological parameters. Due to their wide distribution along both coasts of the sub-continent, South American sea lions (Otaria byronia) provide a valuable opportunity to study the behavioral a...

Sexual segregation in habitat use is widely reported in many taxa and can profoundly influence the distribution and behaviour of animals. However, our knowledge of the mechanisms driving sexual segregation is still in its infancy (particularly in marine taxa) and the influence of extrinsic factors in mediating the expression of sex differences in f...