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Managing oxidative stress is an important physiological function for all aerobic organisms, particularly during periods of prolonged high metabolic activity, such as long‐distance migration across ecological barriers. However, no previous study has investigated the oxidative status of birds at different stages of migration and whether that oxidative status depends on the condition of the birds. In this study, we compared (1) energy stores and circulating oxidative status measures in (a) two species of Neotropical migrants with differing migration strategies that were sampled at an autumn stopover site before an ecological barrier; and (b) a species of trans‐Saharan migrant sampled at a spring stopover site after crossing an ecological barrier; and (2) circulating oxidative measures and indicators of fat metabolism in a trans‐Saharan migrant after stopovers of varying duration (0–8 nights), based on recapture records. We found fat stores to be positively correlated with circulating antioxidant capacity in Blackpoll Warblers and Red‐eyed Vireos preparing for fall migration on Block Island, USA, but uncorrelated in Garden Warblers on the island of Ponza, Italy, after a spring crossing of the Sahara Desert and Mediterranean Sea. In all circumstances, fat stores were positively correlated with circulating lipid oxidation levels. Among Garden Warblers on the island of Ponza, fat anabolism increased with stopover duration while oxidative damage levels decreased. Our study provides evidence that birds build antioxidant capacity as they build fat stores at stopover sites before long flights, but does not support the idea that antioxidant stores remain elevated in birds with high fuel levels after an ecological barrier. Our results further suggest that lipid oxidation may be an inescapable hazard of using fats as the primary fuel for flight. Yet, we also show that birds on stopover are capable of recovering from the oxidative damage they have accrued during migration, as lipid oxidation levels decrease with time on stopover. Thus, the physiological strategy of migrating songbirds may be to build prophylactic antioxidant capacity in concert with fuel stores at stopover sites before a long‐distance flight, and then repair oxidative damage while refueling at stopover sites after long‐distance flight. Our study is the first to show that free‐living migratory songbirds build circulating antioxidant capacity as they do fat stores before long flights, and that songbirds recover from oxidative damage while on stopover after long flights. These findings are key to understanding the physiological ecology of birds during migration.

A 21‐year old female with diabetes mellitus type 1 presented to our hospital's emergency department having suffered from shortness of breath, mild chest pain, and vomiting following her arrival after a long‐distance flight two days earlier. Symptoms had since subsided and physical examination was normal. Blood analysis revealed increased D‐dimers and diabetic ketoacidosis. Computed tomography (CT) examination excluded pulmonary embolism but demonstrated significant mediastinal emphysema. After conservative treatment including nasal oxygen and adjustment of insulin therapy, follow‐up low‐dose CT after four days confirmed full regression of the emphysema. The patient was discharged feeling well, with a recommendation for improved diabetes treatment. Spontaneous pneumomediastinum is a rare condition occurring in younger patients without trauma or pulmonary disease. Over‐inflation and/or pulmonary vasoconstriction have been proposed as major physiological contributors and were likely evoked in the present case by increased respiratory drive due to ketoacidosis and hypoxic vasoconstriction during long distance flight. Spontaneous pneumomediastinum (SPM) is a rare differential diagnosis of acute chest pain and dyspnoea. Clinical symptoms may be subtle. A number of risk factors increase the chance of SPM. SPM normally regresses spontaneously within a few days. We present a 21‐year‐old female with diabetes mellitus type 1 diagnosed with SPM which improved after four days with conservative treatment.

Understanding how free-ranging birds react to approaching aircraft can provide the foundation for predicting and mitigating risk of bird strikes. We characterized responses by avian species to aircraft (propeller-driven, jet, rotorcraft) approach (taxi, takeoffs, landings) at Burke Lakefront Airport, Cleveland, Ohio, USA, from June 2015 through September 2016. Based on opportunistic observations from fixed points on the airfield, we quantified 208 bird-aircraft interactions across 16 species. However, we focused analyses on 5 species with >10 bird-aircraft interactions (n = 176): American kestrel (Falco sparvarious), European starling (Sturnus vulgaris), killdeer (Charadrius vociferous), mourning dove (Zenaida macroura), and red-winged blackbird (Agelaius phoeniceus). We evaluated the common measure of perceived risk, flight-initiation distance (FID), and the likelihood of response (i.e., a measureable FID), each relative to species, flock size, flock altitude, perch height, aircraft approach category, and airframe type. We also assessed effects of light, temperature, and wind speed. None of our predictors contributed to FID. Across the 5 species, birds exposed to direct aircraft approach were ≥2 times more likely to initiate escape as those approached tangentially. The larger mourning dove was, by a factor ≥2, more likely to initiate escape response. As flock size increased, birds were more likely to initiate escape response. Birds were >2 times more likely to initiate escape when approaches involved jets relative to propeller-driven airframes. Because smaller species were less likely to initiate escape response, thereby enhancing the possibility of latent responses close to aircraft, we suggest that airport biologists should not disregard management to reduce strike hazards posed by smaller species. Further, bird habitat on airfields and fixtures that concentrate bird use in a direct line of aircraft approach will inherently increase the frequency of bird-aircraft interactions. Finally, our findings on flock size and airframe type underscore the need for continued efforts to develop methods to enhance avian detection of and response to approaching aircraft.

Anthropogenic disturbance can degrade the quality of stopover sites for migratory shorebirds. We investigated the potential effects of pedestrian traffic and shellfishing on foraging shorebirds at a key stopover site at Monomoy National Wildlife Refuge (Monomoy Refuge), Massachusetts, USA. We experimentally approached 11 species of shorebirds to quantify flight-initiation distances (FID) and found that species and age affected FID. Smaller Calidris sandpipers generally allowed pedestrians to approach within 25 m before flushing, whereas larger shorebirds (black-bellied plover [Pluvialis squatarola] and American oystercatcher [Haematopus palliatus]) had FID over 50 m. We also found that juveniles of all species had shorter FID than adults. Based on adult FID, we developed species-specific buffer distances for 11 species that ranged from 61 m for least sandpiper (Calidris minutilld) to 186 m for black-bellied plover. We also investigated the potential impacts of commercial and recreational shellfish harvesters, who rake forsoftshell clams (Mya arenaria) on mudflats where shorebirds actively foraged. Microhabitats with recent shellfishing activity had a positive influence on the density of 2 species (ruddy turnstone [Arenaria interpres], and American oystercatcher), whereas the presence of shellfishers did not appear to affect the density of other species of shorebird we monitored. We regularly detected black-bellied plovers and ruddy turnstones actively foraging in microhabitats where shellfishers had recently exposed sediment. Given the levels of shellfishing and pedestrian traffic at Monomoy Refuge, we found no evidence to suggest that current human activity has a strong negative impact on migratory shorebirds using Monomoy Refuge. However, if the amount of pedestrian traffic and shellfishing were to increase substantially, a buffer zone system might have to be implemented during peak migration periods to minimize impacts, with buffers > 185 m from key foraging sites to reduce disturbance to the most sensitive species.

Mercury is a global pollutant that has been widely shown to adversely affect reproduction and other endpoints related to fitness and health in birds, but almost nothing is known about its effects on migration relative to other life cycle processes. Here I consider the physiological and histological effects that mercury is known to have on non-migrating birds and non-avian vertebrates to identify potential mechanisms by which mercury might hinder migration performance. I posit that the broad ability of mercury to inactivate enzymes and compromise the function of other proteins is a single mechanism by which mercury has strong potential to disrupt many of the physiological processes that make long-distance migration possible. In just this way alone, there is reason to expect mercury to interfere with navigation, flight endurance, oxidative balance, and stopover refueling. Navigation and flight could be further affected by neurotoxic effects of mercury on the brain regions that process geomagnetic information from the visual system and control biomechanics, respectively. Interference with photochemical reactions in the retina and decreases in scotopic vision sensitivity caused by mercury also have the potential to disrupt visual-based magnetic navigation. Finally, migration performance and possibly survival might be limited by the immunosuppressive effects of mercury on birds at a time when exposure to novel pathogens and parasites is great. I conclude that mercury pollution is likely to be further challenging what is already often the most difficult and perilous phase of a migratory bird’s annual cycle, potentially contributing to global declines in migratory bird populations.

The spongy moth (formerly known as a gypsy moth), Lymantria dispar L. (Lepidoptera: Erebidae), is a polyphagous pest that defoliates various species of trees in the genera Populus, Salix, Quercus, Acer and Pinus. Egg masses of Asian spongy moths (Lymantria dispar asiatica) were obtained from five geographically distinct locations in China (Chengdu, Xifeng, Heilongjiang, Kuduer and Longhua regions) and were carried to the lab for incubation and rearing larvae up to adult emergence. The aim was to see how locality, age and mating status influenced the flying activity of female Asian spongy moths. The findings demonstrate that age significantly affects L. dispar asiatica flying activity, with flight period and distance decreasing dramatically as age increases. Locality also significantly impacts flight ability, and mating status does not affect the L. dispar asiatica female flight ability (p > 0.05). The maximum speed was observed for females from Xifeng (7.19 ± 0.34 km/h). The females from Heilongjiang were recorded as having the maximum average speed (2.35 ± 0.08 km/h). Females from Xifeng exhibited the maximum flight duration and distance (0.94 ± 0.04 h and 1.87 ± 0.18 km). Morphological features, i.e., thorax width (cm) and wing loading, significantly influenced the L. dispar asiatica flight ability (R2 = 0.93 and R2 = −0.98). The overall pattern observed for female L. dispar asiatica flight duration was Xifeng > Kuder > Chengdu > Heilongjiang > Longhua, and for flight distance, it was Xifeng > Longhua > Heilongjiang > Kuder > Chengdu. This research offers detailed information on the dispersion rate of Spongy moths in a known or newly introduced habitat, which can help us limit the spread of this polyphagous pest.

Numerous species have adapted to humans, especially invasive species associated with humans in towns and cities. Short flight distances of populations adapted to urban environments reflect changes in behavior and physiology, reflecting phenotypic plasticity or evolution. Here, I tested the hypothesis that the decrease in flight distance to a potential predator (an approaching human) reflected adaptation to urbanization, using a data set of flight distances of 44 common species of European birds in different stages of adaptation to urban environments. Urban populations had consistently shorter flight distances than rural populations of the same species. Variation in relative flight distance of urban populations was predicted by the number of generations since urbanization, as expected by a gradual process of adaptation. Furthermore, species with relatively large populations in urban environments would be an indication of local adaptation to urban environments. Relative flight distance of urban population was shorter for species with large populations in urban compared to rural habitats. Species that had adapted to urban environments as shown by short flight distances were less susceptible to predation by the European sparrowhawk Accipiter nisus than species with relatively long flight distances in urban populations. These findings provide evidence consistent with the hypothesis that recent changes in the tameness of urban birds, as reflected by their relatively short flight distances, is an adaptation to the novel urban environment.

In this paper, we consider a wireless sensor network consisting of an unmanned aerial vehicle (UAV) acting as a sink node and a number of sensor nodes scattered uncertainly on the ground. In the network, the UAV flies to a spatial point called point of interest and hovers to collect environmental data from neighboring sensor nodes. Then, the UAV proceeds to the next point of interest. The UAV must gather data from all the sensor nodes. On the other hand, a shorter round-trip air route of the UAV is more preferred since a battery-operated UAV needs regular recharging. To satisfy the requirement and to adhere to the recommendation as well, especially in the situation where only vague locational information about sensor nodes is available, we propose a scheme that follows three steps. First, it covers the sensor field of the wireless sensor network with three categories of hexagonal tessellations. Secondly, it establishes a point of interest at the centroid of each tile. Thirdly, it constructs an air route of the UAV, which visits every point of interest along a Hamiltonian cycle on the induced graph. Next, we develop a closed-form expression for the exact flight distance attained by the proposed scheme. For comparative evaluation, we discover some optimal schemes that minimize the flight distance by completely inspecting all patterns and corroborating the property of Hamiltonicity. The flight distance along the air route constructed by the proposed scheme is found to be only slightly longer than the flight distance yielded by an optimal scheme. Furthermore, the proposed scheme is proven to be practically valid when a common multicopter is employed as the sink node.

The analysis of the stability of human gait may be effectively performed when estimates of the base of support are available. The base of support area is defined by the relative position of the feet when they are in contact with the ground and it is closely related to additional parameters such as step length and stride width. These parameters may be determined in the laboratory using either a stereophotogrammetric system or an instrumented mat. Unfortunately, their estimation in the real world is still an unaccomplished goal. This study aims at proposing a novel, compact wearable system, including a magneto-inertial measurement unit and two time-of-flight proximity sensors, suitable for the estimation of the base of support parameters. The wearable system was tested and validated on thirteen healthy adults walking at three self-selected speeds (slow, comfortable, and fast). Results were compared with the concurrent stereophotogrammetric data, used as the gold standard. The root mean square errors for the step length, stride width and base of support area varied from slow to high speed between 10–46 mm, 14–18 mm, and 39–52 cm2, respectively. The mean overlap of the base of support area as obtained with the wearable system and with the stereophotogrammetric system ranged between 70% and 89%. Thus, this study suggested that the proposed wearable solution is a valid tool for the estimation of the base of support parameters out of the laboratory.

Airway network optimization is crucial for airspace planning, addressing high traffic density and alleviating pressure on Air Traffic Controllers. With the rapid growth of civil aviation, overloaded airways and congestion have become significant challenges. Vietnam’s air transport sector plays a vital role in economic and social development, enhancing connectivity across the Asia-Pacific region. Additionally, Vietnam has led the global recovery of domestic aviation post-COVID-19 and, as the world’s fifth fastest-growing aviation market, is expected to reach 150 million air transport passengers by 2035. This highlights Vietnam’s dynamic growth and strategic importance within global aviation. However, this rapid expansion has exposed vulnerabilities in Vietnam’s airways, particularly within the Ho Chi Minh Flight Information Region (HCM FIR), where congestion and overload are evident, especially during adverse weather. To address these challenges, this study proposes optimizing the airway network in 2D space using the A-star algorithm, tailored for the HCM FIR. This approach aims to reduce flight distances, improve operational efficiency, and ease ATC workloads, marking a critical step toward enhancing Vietnam’s airspace management system.