Greg A. Breed

Seabirds are critical ecosystem members providing connectivity between marine and terrestrial ecosystems. Seabird foraging is often facilitated by other marine predators (e.g. tuna) that aggregate prey at the surface. Some seabirds have been anecdotally reported to ‘hawk’ (catch mid-air/in-flight) flyingfish and flying squid forced into flight by subsurface predators. Hawking avoids water entry and subsequent take-off, both of which are known to be energy intensive, but its relative importance in foraging has not been quantified. We analysed footage from 25 animal-borne video cameras deployed on red-footed boobies (Sula sula) at Palmyra Atoll to estimate the frequency of hawking, plunge diving and ‘other’ prey capture attempts. Hawking made up 20.3% of all prey capture attempts and had a 39.3% success rate in 2022, but was not observed for the two tracked birds in 2024. An additional 17 individuals were opportunistically observed in the footage making hawking capture attempts, suggesting hawking is a common behaviour, accounting for a greater proportion of foraging effort than previously known. As hawking is only possible when subsurface predators elicit flight escape behaviours of prey, its high frequency suggests such predator facilitation interactions are stronger than currently understood.

Aim: Site network approaches to waterbird conservation are easily biased towards species that occur in high densities and locations and periods of the annual cycle with dense concentrations of birds, thereby potentially failing to address underlying factors driving certain population declines. Here, for shorebird populations that migrate along the East Asian–Australasian Flyway, we examine the extent to which recent conservation efforts at key sites in the Yellow Sea—that is, sites that are vital for stabilising densely concentrated , rapidly declining shorebird species—might address factors underlying low adult survival and steep population declines in shorebird species that migrate and winter along a broad front (i.e., the East China Sea, Yellow Sea and Japan). Location: East Asia. Methods and Results: Using geolocator‐derived migration tracks, an integrated survival model and a population matrix model to estimate winter‐population‐specific survival rates and population trends in a quintessential East Asian shorebird population—the arcticola subspecies of the Dunlin ( Calidris alpina )—we show that in 2010–2014 differences between arcticola winter populations in the intensity of their declines were most likely linked to conditions on their wintering grounds, with individuals that wintered in the East China Sea or Japan showing the steepest population declines (mean: −12% year ⁻¹ [50% credible interval: −3%, −22%] and −17% year ⁻¹ [−6%, −30%], respectively) and individuals that wintered in the Yellow Sea surprisingly stable (+4% year ⁻¹ [−5%, +14%]). Main Conclusions: For shorebird populations that winter in East Asia and migrate along a broad front, additional conservation efforts in the East China Sea and Japan are likely necessary to reverse population declines.

We fit ongoing 40+-year mark-recapture databases from the thriving southern right whale (SRW), Eubalaena australis , and highly endangered North Atlantic right whale (NARW), Eubalaena glacialis , to candidate survival models to estimate their life spans. Median life span for SRW was 73.4 years, with 10% of individuals surviving past 131.8 years. NARW life spans were likely anthropogenically shortened, with a median life span of just 22.3 years, and 10% of individuals living past 47.2 years. In the context of extreme longevity recently documented in other whale species, we suggest that all balaenid and perhaps most great whales have an unrecognized potential for great longevity that has been masked by the demographic disruptions of industrial whaling. This unrecognized longevity has profound implication for basic biology and conservation of whales.

Warming sea surface temperatures (SSTs) are altering the biological structure of intertidal wetlands at a global scale, with potentially serious physiological and demographic consequences for migratory shorebird populations that depend on intertidal sites. The effects of mediating factors, such as age-related foraging skill, in shaping the consequences of warming SSTs on shorebird populations, however, remain largely unknown. Using morphological measurements of Dunlin fuelling for a >3000 km transoceanic migration, we assessed the influence of climatic conditions and age on individuals’ migratory fuel loads and performance. We found that juveniles were often at risk of exhausting their fuel loads en route to primary wintering grounds, especially following high June SSTs in the previous year; the lagged nature of which suggests SSTs acted on juvenile loads by altering the availability of critical prey. Up to 45% fewer juveniles may have reached wintering grounds via a non-stop flight under recent high SSTs compared to the long-term trend. Adults, by contrast, were highly capable of reaching wintering grounds in non-stop flight across years. Our findings suggest that juveniles were disproportionately impacted by apparent SST-related declines in critical prey, and illustrate a general mechanism by which climate change may shape migratory shorebird populations worldwide.

Wildfire is the most important disturbance regime in North American boreal forest communities, driving forest composition and structure across this region. Recent climate models predict that increasing fire intensity and frequency will result in a shift from a largely coniferous forest to one with a greater dominance by deciduous species. We investigated how an iconic predator of the boreal system, the Canada lynx (Lynx canadensis), moves through a range of burn scars (2-78 years old) and if these movements reflect habitat selection of their main prey, the snowshoe hare (Lepus americanus). Using GPS collars at 4-h fix rates, we fitted integrated step selection models to lynx movements across an 80-year post-fire chronosequence to assess habitat selection in both deciduous and coniferous forests. We predicted that lynx would primarily select intermediately-aged spruce, but young deciduous stands, mirroring the habitat selection of snowshoe hares. We found, however, that lynx habitat selection peaked at intermediately aged stands in both forest types. We hypothesize that this difference is driven by selection for habitats that maximize capture probability as opposed to simply representing the highest hare density. This idea is supported by observed seasonal changes in peak selection in deciduous stands, with selection for younger stands in winter, when leaf loss reduces cover. There was no seasonal change in coniferous stands as they experience little change in cover across seasons. Together these results show that lynx can be resilient to short-term shifts toward intermediate-aged stands. However, these benefits will likely diminish in the longer term as the decrease in fire return interval may reduce the prevalence of intermediate-age stands.

Climate warming can cause arthropods to express plastic and/or evolved changes in morphology. Previous studies have demonstrated that body sizes of Arctic butterflies are influenced by the temperatures experienced as larvae. To investigate whether this was occurring among Alaskan butterflies, we analyzed temporal trends in the wing sizes of three Holarctic species, Colias hecla , Boloria chariclea and Boloria freija , using museum specimens collected in Arctic tundra regions of Alaska between 1971 and 1995. Wing length was compared to accumulated growing degree days (GDD) during both the spring of the year collected and the previous year's summer during the normal period of larval development. We used mixed‐effects models to test if spring and summer temperatures affected adult morphology. Results show that for every 1°C increase in average seasonal temperature, wingspans decreased between 0.7 and 5 mm, with B. freija the most strongly affected. Our results suggest that the morphological sensitivity of Arctic butterflies to warming is the outcome of interactions between life‐history traits and regional climate, with all species sensitive to warming the summer before the flight year as well as warming the spring of the flight year. Boloria freija , which overwinters as late instar larvae that do not feed before pupation the following spring, was particularly strongly affected by summer warming.

Rapid sea-ice decline and warmer waters are threatening the stability of Arctic ecosystems and potentially forcing their restructuring. Mathematical models that support observational evidence are becoming increasingly important. We develop a food web model for the Southern Beaufort Sea based on species with high ecological significance. Generalized modeling is applied to study the impact of realistic characteristics on food web stability; a powerful method that provides a linear stability analysis for systems with uncertainty in data and underlying physical processes. We find that including predator-specific foraging traits, weighted predator–prey interactions, and habitat constraints increase food-web stability. The absence of a fierce top predator (killer whale, polar bear, etc.) also significantly increases the portion of stable webs. Adding ecosystem background noise in terms of a collective impact of latent, minor ecosystem members shows a peak in stability at an optimum, relatively small background pressure. These results indicate that refining models with more realistic detail to account for the complexity of the ecological system may be key to bridge the gap between empirical observations and model predictions in ecosystem stability.

Step selection analysis (SSA) is a common framework for understanding animal movement and resource selection using telemetry data. Such data are, however, inherently autocorrelated in space, a complication that could impact SSA‐based inference if left unaddressed. Accounting for spatial correlation is standard statistical practice when analysing spatial data, and its importance is increasingly recognized in ecological models (e.g. species distribution models). Nonetheless, no framework yet exists to account for such correlation when analysing animal movement using SSA. Here, we extend the popular method integrated step selection analysis (iSSA) by including a Gaussian field (GF) in the linear predictor to account for spatial correlation. For this, we use the Bayesian framework R‐INLA and the stochastic partial differential equations (SPDE) technique. We show through a simulation study that our method provides accurate fixed effects estimates, quantifies their uncertainty well and improves the predictions. In addition, we demonstrate the practical utility of our method by applying it to three wolverine (Gulo gulo) tracks. Our method solves the problems of assuming spatially independent residuals in the SSA framework. In addition, it offers new possibilities for making long‐term predictions of habitat usage.

Climate warming can cause arthropods to express plastic and/or evolved changes in morphology. Previous studies have demonstrated that body sizes of Arctic butterflies are influenced by the temperatures experienced as larvae. To investigate whether this was occurring among Alaskan butterflies, we analyzed temporal trends in the wing sizes of three Holarctic species, Colias hecla, Boloria chariclea, and Boloria freija, using museum specimens collected in Arctic tundra regions of Alaska between 1971 and 1995. Wing length was compared to accumulated growing degree days (GDD) during both the spring of the year collected and the previous year’s summer during the normal period of larval development. We used mixed-effects models to test if spring and summer temperatures affected adult morphology. Results show that for every 1°C increase in average seasonal temperature, wingspans decreased between 0.7 millimeters and 5 millimeters, with B. freija the most strongly affected. Our results suggest that the morphological sensitivity of Arctic butterflies to warming is the outcome of interactions between life-history traits and regional climate, with all species sensitive to warming the summer before the flight year as well as warming the spring of the flight year. B. freija, which overwinters as late instar larvae that do not feed before pupation the following spring, was particularly strongly affected by summer warming.

Rapidly advancing animal telemetry technologies paired with new statistical models can provide insight into the behaviour of otherwise unobservable free‐living animals. Changes in behaviour apparent from pairing telemetry with statistical models often occur as animals undertake key life‐history activities, such as reproduction. For many species that are secretive or occupy remote areas, these life‐history events are difficult to detect with conventional survey techniques, and consequently, vital rates are difficult to estimate. We present a hierarchical modelling framework, which integrates movement data observed via animal‐borne telemetry and optional, infrequent survey data, to estimate individual‐ and population‐level reproductive success. The approach combines a mechanistic movement model and survival model, and allows for assessing the effects of hypothesized individual and environmental covariates on reproductive success. We first tested our approach with simulated data, and then applied it to movement data from migratory golden eagles (Aquila chrysaetos) breeding in southcentral Alaska across four breeding seasons. We show that results supported our biological hypotheses that changes in movement coincided with the timing of reproductive failures, and that changes in movement could be used to assess breeding success (and failure) at the individual and population levels. The analysis also provided evidence of inter‐annual variation in population‐level nest success and the timing of nesting failures. This new approach is adaptable to many species that care for young and can be tracked with telemetry devices, and can provide not only individual‐level information useful for testing ecological hypotheses, but estimates of demographic parameters that can directly inform conservation and management if tagged animals are representative of the population.