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Declining sea ice and increased variability in sea ice dynamics are altering Arctic marine food webs. Changes in sea ice dynamics and prey availability are likely to impact pagophilic (ice-dependent and ice-associated) species, such as thick-billed murres (Uria lomvia), through changes in foraging behaviour and foraging success. At the same time, extrinsic factors, such as chick demand, and intrinsic factors, such as sex, are also likely to influence foraging behaviour and foraging success of adult murres. Here, we use 3 years of data (2017–2019) to examine the impacts of environmental conditions (sea ice concentration and sea surface temperature), sex and chick age (as a proxy for chick demand) on foraging and diving behaviour (measured via biologgers), energy expenditure (estimated from activity budgets) and foraging success (measured via nutritional biomarkers) of thick-billed murres during the incubation and chick-rearing stages at Coats Island, Nunavut. Murres only exhibited foraging flexibility to environmental conditions during incubation, which is also the only stage when ice was present. When more ice was present, foraging effort increased, murres foraged farther and made deeper dives, where murres making deeper dives had higher foraging success (greater relative change in mass). During incubation, murre behaviour was also influenced by sex of the individual, where males made more and shorter trips and more dives. During chick-rearing, murre behaviour was influenced primarily by the sex of the individual and chick age. Males made shallower dives and fewer dive bouts per day, and more dives. Birds made longer, deeper dives as chicks aged, likely representing increased intra-specific competition for prey throughout the season. Our results suggest variation in sea ice concentration does impact foraging success of murres; however, sex-specific foraging strategies may help buffer colony breeding success from variability in sea ice concentration. [ABSTRACT FROM AUTHOR]

The degree to which individuals adjust foraging behavior in response to environmental variability can impact foraging success, leading to downstream impacts on fitness and population dynamics. We examined the foraging flexibility, average daily energy expenditure, and foraging success of an ice‐associated Arctic seabird, the thick‐billed murre (Uria lomvia) in response to broad‐scale environmental conditions at two different‐sized, low Arctic colonies located <300 km apart. First, we compared foraging behavior (measured via GPS units), average daily energy expenditure (estimated from GPS derived activity budgets), and foraging success (nutritional state measured via nutritional biomarkers pre‐ and post‐ GPS deployment) of murres at two colonies, which differ greatly in size: 30,000 pairs breed on Coats Island, Nunavut, and 400,000 pairs breed on Digges Island, Nunavut. Second, we tested whether colony size within the same marine ecosystem altered foraging behavior in response to broad‐scale environmental variability. Third, we tested whether environmentally induced foraging flexibility influenced the foraging success of murres. Murres at the larger colony foraged farther and longer but made fewer trips, resulting in a lower nutritional state and lower foraging success compared to birds at the smaller colony. Foraging behavior and foraging success varied in response to environmental variation, with murres at both colonies making longer, more distant foraging trips in high ice regimes during incubation, suggesting flexibility in responding to environmental variability. However, only birds at the larger colony showed this same flexibility during chick rearing. Foraging success at both colonies was higher during high ice regimes, suggesting greater prey availability. Overall, murres from the larger colony exhibited lower foraging success, and their foraging behavior showed stronger responses to changes in broad‐scale conditions such as sea ice regime. Taken together, this suggests that larger Arctic seabird colonies have higher behavioral and demographic sensitivity to environmental change. [ABSTRACT FROM AUTHOR]

The behavior of many wild animals remains a mystery, as it is difficult to quantify behavior of species that cannot be easily followed throughout their daily or seasonal movements. Accelerometers can solve some of these mysteries, as they collect activity data at a high temporal resolution (<1 s), can be relatively small (<1 g) so they minimally disrupt behavior, and are increasingly capable of recording data for long periods. Nonetheless, there is a need for increased validation of methods to classify animal behavior from accelerometers to promote widespread adoption of this technology in ecology. We assessed the accuracy of six different behavioral assignment methods for two species of seabird, thick‐billed murres (Uria lomvia) and black‐legged kittiwakes (Rissa tridactyla). We identified three behaviors using tri‐axial accelerometers: standing, swimming, and flying, after classifying diving using a pressure sensor for murres. We evaluated six classification methods relative to independent classifications from concurrent GPS tracking data. We used four variables for classification: depth, wing beat frequency, pitch, and dynamic acceleration. Average accuracy for all methods was >98% for murres, and 89% and 93% for kittiwakes during incubation and chick rearing, respectively. Variable selection showed that classification accuracy did not improve with more than two (kittiwakes) or three (murres) variables. We conclude that simple methods of behavioral classification can be as accurate for classifying basic behaviors as more complex approaches, and that identifying suitable accelerometer metrics is more important than using a particular classification method when the objective is to develop a daily activity or energy budget. Highly accurate daily activity budgets can be generated from accelerometer data using multiple methods and a small number of accelerometer metrics; therefore, identifying a suitable behavioral classification method should not be a barrier to using accelerometers in studies of seabird behavior and ecology. [ABSTRACT FROM AUTHOR]

Stressful environmental conditions affect the adrenocortical function of developing animals, which can have consequences for their fitness. Discovery of the avian stress hormone corticosterone (CORT) in feathers has the potential to broaden the application of endocrine research in ecological and evolutionary studies of wild birds by providing a long-term measure of CORT secretion. Mechanisms of CORT deposition in feathers are not well known and few studies have related feather CORT to circulating plasma CORT during feather growth. Our objective was to experimentally test the validity of using feather CORT as a measure of CORT secretion in developing birds experiencing nutritional stress. Caspian tern Hydroprogne caspia chicks were fed ad libitum or restricted (35% less than ad libitum) diets for four weeks. We measured CORT in feathers from these chicks to examine the relationship between feather CORT concentrations and nutritional limitation, circulating plasma CORT, and feather development. We found that feather CORT was higher in controls fed ad libitum than in restricted individuals, despite higher levels of plasma CORT in restricted chicks compared to controls. Feather mass and growth rates were strongly and positively related to feather CORT concentrations in both treatments. This is the first experimental study to show that feather CORT concentrations can be lower in response to nutritional stress, even when plasma CORT concentrations are elevated. Our results indicate that CORT deposition in feathers may be confounded when feather mass and growth rates are compromised by nutritional stress. We conclude that feather CORT can be used for assessing nutritional stress in growing birds, but the direction of response depends on how strongly stress affects feather development. [ABSTRACT FROM AUTHOR]

Resort development and coastal beach erosion have led to declines in beach breeding habitat for the near-threatened Malaysian Plover (Charadrius peronii) in the Gulf of Thailand. Semi-natural saltflats may provide supplementary nesting areas. We compared the environmental conditions, incubation behaviour and nesting success of plovers breeding on sandy beaches and saltflats in Thailand. In total we monitored 21 and nine nesting attempts in 2004 (beaches and saltflats, respectively) and 26 and 22 nesting attempts in 2005. Despite higher air temperatures in the saltflats (P < 0.0001), we detected no significant differences in nest attendance (P = 0.542 and P = 0.885 for 2004 and 2005, respectively), number of incubator changes between parents (P = 0.776 and P = 0.823) or number of parental nest departures (P = 0.087 and P = 0.712) during 120 incubation observations on 55 nests. There was also no difference in hatching success between beaches in 2004 (beach = 0.65, saltflat = 0.55; P = 0.692, n = 26) and 2005 (beach = 0.46, saltflat = 0.35; P = 0.539, n = 41). These results suggest that saltflats may provide nesting habitat for Malaysian Plovers and could help enhance overall hatching success rates by reducing nesting densities on beaches. Although there are few remaining intact saltflats in coastal Thailand, there are currently vast areas of abandoned tiger prawn aquaculture ponds that could be rehabilitated into saltflats at relatively low cost. Given the large area of disused aquaculture ponds throughout Thailand and South-East Asia and the substantial human pressure on coastal habitats, there could be considerable conservation benefits to the restoration of aquaculture ponds. [ABSTRACT FROM PUBLISHER]

The researchers conducted a qualitative case study on a learning community comprising special education and psychology majors. This community was strategically organized to foster interdisciplinary learning among its members and to design interventions for students struggling with mathematics anxiety, specifically in classes like Algebra 1. Working alongside a university faculty member and a graduate student, the undergraduates applied mental health principles from psychology research to real-world situations. Their efforts included teaching Algebra 1 to a student grappling with both a learning disability in mathematics and mathematics anxiety. In their approach, the group utilized mindfulness principles to tailor conversations to the high school student's interests, effectively incorporating mindfulness techniques into the mathematics tutoring sessions. This approach proved successful, particularly when the student was experiencing high levels of anxiety, enabling significant progress in his Algebra 1 work. The collaborative efforts also provided substantial benefits to the college students, who learned about each other's fields of study They effectively combined this knowledge in practical ways and applied it in real-world settings. The findings of this study offer important insights for the training of pre-service special education teachers and college students in related fields. [ABSTRACT FROM AUTHOR]

Daily energy expenditure (DEE) is the result of decisions on how to allocate time among activities (resting, commuting and foraging) and the energy costs of those activities. Dynamic body acceleration (DBA), which measures acceleration associated with movement, can be used to estimate DEE. Previous studies of DBA-DEE correlations in birds were carried out on species foraging below their thermoneutral zone, potentially decoupling the DBA-DEE relationship. We used doubly labelled water (DLW) to validate the use of DBA on plunge-diving seabirds, Peruvian boobies (Sula variegata), foraging in waters above their thermoneutral zone (>19°C). Mass-specific DEEDLW in boobies was 1.12 kJ day-1 g-1, and higher in males than in females. DBA alone provided the best fitting model to estimate mass-specific DEEDLW compared with models partitioned per activity and time budget models. Nonetheless, the model parametrizing activity at and away from their onshore breeding colony was the most parsimonious (r=0.6). This r value, although high, is lower than that of all other avian studies, implying that temperature is not the main cause of DBA-DEE decoupling in birds. Time at the colony (∼80% of the day) was the largest contributor to DEE as it was the most time-consuming activity and involved nest defence. However, foraging was the most power-consuming activity (4.6 times higher activity-specific metabolic rate than resting at the colony), and commuting flight was higher than in other gliding seabirds. In short, DBA alone can act as a proxy for DEE, opening avenues to measure the conservation energetics of this seabird in the rapidly changing Peruvian Humboldt Current system., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2024. Published by The Company of Biologists Ltd.)

Mercury (Hg) is a heterogeneously distributed toxicant affecting wildlife and human health. Yet, the spatial distribution of Hg remains poorly documented, especially in food webs, even though this knowledge is essential to assess large-scale risk of toxicity for the biota and human populations. Here, we used seabirds to assess, at an unprecedented population and geographic magnitude and high resolution, the spatial distribution of Hg in North Atlantic marine food webs. To this end, we combined tracking data of 837 seabirds from seven different species and 27 breeding colonies located across the North Atlantic and Atlantic Arctic together with Hg analyses in feathers representing individual seabird contamination based on their winter distribution. Our results highlight an east-west gradient in Hg concentrations with hot spots around southern Greenland and the east coast of Canada and a cold spot in the Barents and Kara Seas. We hypothesize that those gradients are influenced by eastern (Norwegian Atlantic Current and West Spitsbergen Current) and western (East Greenland Current) oceanic currents and melting of the Greenland Ice Sheet. By tracking spatial Hg contamination in marine ecosystems and through the identification of areas at risk of Hg toxicity, this study provides essential knowledge for international decisions about where the regulation of pollutants should be prioritized., Competing Interests: Competing interests statement:The authors declare no competing interest.

Accelerometry has been widely used to estimate energy expenditure in a broad array of terrestrial and aquatic species. However, a recent reappraisal of the method showed that relationships between dynamic body acceleration (DBA) and energy expenditure weaken as the proportion of non-mechanical costs increases. Aquatic air breathing species often exemplify this pattern, as buoyancy, thermoregulation and other physiological mechanisms disproportionately affect oxygen consumption during dives. Combining biologging with the doubly labelled water method, we simultaneously recorded daily energy expenditure (DEE) and triaxial acceleration in one of the world's smallest wing-propelled breath-hold divers, the dovekie (Alle alle). These data were used to estimate the activity-specific costs of flying and diving and to test whether overall dynamic body acceleration (ODBA) is a reliable predictor of DEE in this abundant seabird. Average DEE for chick-rearing dovekies was 604±119 kJ day-1 across both sampling years. Despite recording lower stroke frequencies for diving than for flying (in line with allometric predictions for auks), dive costs were estimated to surpass flight costs in our sample of birds (flying: 7.24× basal metabolic rate, BMR; diving: 9.37× BMR). As expected, ODBA was not an effective predictor of DEE in this species. However, accelerometer-derived time budgets did accurately estimate DEE in dovekies. This work represents an empirical example of how the apparent energetic costs of buoyancy and thermoregulation limit the effectiveness of ODBA as the sole predictor of overall energy expenditure in small shallow-diving endotherms., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2022. Published by The Company of Biologists Ltd.)

AbstractLife history theory posits that reproduction is constrained by a cost of reproduction such that any increase in breeding effort should reduce subsequent survival. Oxidative stress refers to an imbalance between the prooxidant reactive oxygen species (ROS) and antioxidant defense. If not thwarted, ROS can cause damage to DNA, lipids, and proteins, potentially increasing the rate of senescence and decreasing cellular function. Reproduction is often associated with higher metabolic rates, which could increase production of ROS and lead to oxidative damage if the animal does not increase antioxidant protection. Thus, oxidative stress could be one mechanism creating a cost of reproduction. In this study we explored how reproduction may affect oxidative status differently between male and female thick-billed murres during early and late breeding seasons over three consecutive years. We manipulated breeding efforts by removing an egg from the nest of some individuals, which forced females to relay, and by handicapping other individuals by clipping wings. We measured total antioxidant capacity (TAC), uric acid (UA) concentration, and malondialdehyde (MDA; an index of lipid oxidative damage) concentration in blood plasma as well as activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) in red blood cells. Oxidative status was highly variable across years, and year was consistently the most important factor determining oxidative status; inconsistent results in previous field studies may be because reproductive oxidative stress occurs only in some years. Females had lower SOD and GPx and higher MDA and TAC than males immediately after egg laying, suggesting that the cost of egg laying required investment in cheaper nonenzymatic antioxidant defenses that had lower capacity for defending against lipid peroxidation. Delayed birds had lower UA and lower SOD, GPx, and CAT activity compared with control birds. In conclusion, when reproductive costs increase via higher energy costs or longer breeding seasons, the oxidative status of both male and female murres deteriorated as a result of reduced antioxidant defenses.

Muscle ultrastructure is closely linked with athletic performance in humans and lab animals, and presumably plays an important role in the movement ecology of wild animals. Movement is critical for wild animals to forage, escape predators and reproduce. However, little evidence directly links muscle condition to locomotion in the wild. We used GPS-accelerometers to examine flight behaviour and muscle biopsies to assess muscle ultrastructure in breeding black-legged kittiwakes ( Rissa tridactyla ). Biopsied kittiwakes showed similar reproductive success and subsequent over-winter survival to non-biopsied kittiwakes, suggesting that our study method did not greatly impact foraging ability. Muscle fibre diameter was negatively associated with wing beat frequency, likely because larger muscle fibres facilitate powered flight. The number of nuclei per fibre was positively associated with average air speed, likely because higher power output needed by faster-flying birds required plasticity for muscle fibre recruitment. These results suggest the potential for flight behaviour to predict muscle ultrastructure., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2020. Published by The Company of Biologists Ltd.)

The Arctic is entering a new ecological state, with alarming consequences for humanity. Animal-borne sensors offer a window into these changes. Although substantial animal tracking data from the Arctic and subarctic exist, most are difficult to discover and access. Here, we present the new Arctic Animal Movement Archive (AAMA), a growing collection of more than 200 standardized terrestrial and marine animal tracking studies from 1991 to the present. The AAMA supports public data discovery, preserves fundamental baseline data for the future, and facilitates efficient, collaborative data analysis. With AAMA-based case studies, we document climatic influences on the migration phenology of eagles, geographic differences in the adaptive response of caribou reproductive phenology to climate change, and species-specific changes in terrestrial mammal movement rates in response to increasing temperature., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)