Joint evolution of the biogeography and phenology of seasonal migration.

In migratory species, the temporal phases of the annual cycle are linked to seasonally shifting geographic ranges. Despite intense interest in the annual cycle ecology of migratory species, a synthetic understanding of the relationship between the biogeography of the migratory annual cycle and its phenology remains elusive. Here, we investigate the spatiotemporal structure of the annual cycle in a phylogenetic comparative framework by developing a method to demarcate the pacing of annual cycle stages using eBird, a massive avian occurrence dataset, and applying it to migratory passerine birds breeding in North America.

Migratory herbivorous waterfowl track multiple resource waves during spring migration.

East Asian herbivorous waterfowl intensively use farmland in spring, next to their natural habitat. Accordingly, they might have expanded their migration strategy from merely tracking the green wave of newly emerging vegetation to also incorporating the availability of post-harvest agricultural seeds (here dubbed the seed wave). However, if and how waterfowl use multiple food resources to time their seasonal migration is still unknown.

Addressing critical gaps in protected area coverage for bird habitats in China.

Currently, protected areas cover approximately 14% of the Earth's land surface, yet 12.2% of the world's bird species remain unprotected by any designated areas and face significant threats. This study investigates the current status of bird conservation in China, aiming to evaluate the effectiveness of existing protected areas, analyze why certain bird species are not adequately protected, and propose strategies for optimizing protected area configurations.

Decoupling of bird migration from the changing phenology of spring green-up.

The green-up of vegetation in spring brings a pulse of food resources that many animals track during migration. However, green-up phenology is changing with climate change, posing an immense challenge for species that time their migrations to coincide with these resource pulses. We evaluated changes in green-up phenology from 2002 to 2021 in relation to the migrations of 150 Western-Hemisphere bird species using eBird citizen science data.

Collections of small urban parks consistently support higher species richness but not higher phylogenetic or functional diversity.

When prioritizing regions for conservation protection, decisions are often based on the principle that a single large reserve should support more species than several small reserves of the same total area (SLOSS). This principle remains a central paradigm in conservation planning despite conflicting empirical evidence and methodological concerns. In urban areas where small parks tend to dominate and policies to promote biodiversity are becoming increasingly popular, determining the most appropriate prioritization method is critical.

The surface urban heat island effect decreases bird diversity in Chinese cities.

The audiovisual experience of observing birds in cities provides numerous benefits to residents, but their diversity is endangered by urbanization. Although the magnitude of the surface urban heat island effect (hereafter SUHI) has grown in recent years, its impact on bird diversity has not been adequately investigated. Here, we calculate the SUHI in 336 Chinese cities and we document the implications of the SUHI for avian species richness and functional diversity during the 2001, 2011, and 2019 breeding and non-breeding seasons.

Urbanisation generates multiple trait syndromes for terrestrial animal taxa worldwide.

Cities can host significant biological diversity. Yet, urbanisation leads to the loss of habitats, species, and functional groups. Understanding how multiple taxa respond to urbanisation globally is essential to promote and conserve biodiversity in cities.

The correlation between eBird community science and weather surveillance radar-based estimates of migration phenology.

Aim: Measuring avian migration can prove challenging given the spatial scope and the diversity of species involved. No one monitoring technique provides all the pertinent measures needed to capture this macroscale phenomenon - emphasizing the need for data integration. Migration phenology is a key metric characterizing large-scale migration dynamics and has been successfully quantified using weather surveillance radar (WSR) data and community science observations.

Light pollution enhances ground-level exposure to airborne toxic chemicals for nocturnally migrating passerines.

Anthropogenic activities generate different forms of environmental pollution, including artificial light at night (ALAN) and airborne toxic chemicals (ATCs). Nocturnally migrating birds are attracted to ALAN during migration and if ALAN occurs in unison with ATC, the chances of ground-level ATC contamination occurring at stopover sites could increase. Here, we document the relationship between ALAN and ATC within the contiguous United States based on 479 toxic chemicals from 15,743 releasing facilities.

Estimating the movements of terrestrial animal populations using broad-scale occurrence data.

As human and automated sensor networks collect increasingly massive volumes of animal observations, new opportunities have arisen to use these data to infer or track species movements. Sources of broad scale occurrence datasets include crowdsourced databases, such as eBird and iNaturalist, weather surveillance radars, and passive automated sensors including acoustic monitoring units and camera trap networks. Such data resources represent static observations, typically at the species level, at a given location.

Seasonal variation in the effects of artificial light at night on the occurrence of nocturnally migrating birds in urban areas.

Urban areas often contain large numbers of migratory bird species during seasonal migration, many of which are nocturnal migrants. How artificial light at night (ALAN) and urban landcover are associated with the diurnal occurrence of nocturnal migrants within urban areas across seasons has not been explored. Here, we use eBird bird occurrence information to estimate the seasonal species richness of nocturnally migrating passerines (NMP) within 333 well surveyed urban areas within the contiguous USA.

Phenological synchronization of seasonal bird migration with vegetation greenness across dietary guilds.

The seasonal movement of animals has been linked to seasonal variation in ecological productivity, and it has been hypothesized that primary consumers synchronize migration with vegetation phenology. Within temperate regions of the Northern Hemisphere, herbivorous bird species often track the phenology of vegetation greenness during spring migration. Phenological synchronization with vegetation greenness by migratory birds in other dietary guilds, across the full extent of their annual distributions during both spring and autumn migration, has not been explored.

Higher Nest Predation Favors Rapid Fledging at the Cost of Plumage Quality in Nestling Birds.

High predation risk can favor rapid offspring development at the expense of offspring quality. Impacts of rapid development on phenotypic quality should be most readily expressed in traits that minimize fitness costs. We hypothesize that ephemeral traits that are replaced or repaired after a short period of life might express trade-offs in quality as a result of rapid development more strongly than traits used throughout life.

Holding steady: Little change in intensity or timing of bird migration over the Gulf of Mexico.

Quantifying the timing and intensity of migratory movements is imperative for understanding impacts of changing landscapes and climates on migratory bird populations. Billions of birds migrate in the Western Hemisphere, but accurately estimating the population size of one migratory species, let alone hundreds, presents numerous obstacles. Here, we quantify the timing, intensity, and distribution of bird migration through one of the largest migration corridors in the Western Hemisphere, the Gulf of Mexico (the Gulf).

Projected changes in wind assistance under climate change for nocturnally migrating bird populations.

Current climate models and observations indicate that atmospheric circulation is being affected by global climate change. To assess how these changes may affect nocturnally migrating bird populations, we need to determine how current patterns of wind assistance at migration altitudes will be enhanced or reduced under future atmospheric conditions. Here, we use information compiled from 143 weather surveillance radars stations within the contiguous United States to estimate the daily altitude, density, and direction of nocturnal migration during the spring and autumn.

Seasonal abundance and survival of North America's migratory avifauna determined by weather radar.

Avian migration is one of Earth's largest processes of biomass transport, involving billions of birds. We estimated continental biomass flows of nocturnal avian migrants across the contiguous United States using a network of 143 weather radars. We show that, relative to biomass leaving in autumn, proportionally more biomass returned in spring across the southern United States than across the northern United States.

Navigating north: how body mass and winds shape avian flight behaviours across a North American migratory flyway.

The migratory patterns of birds have been the focus of ecologists for millennia. What behavioural traits underlie these remarkably consistent movements? Addressing this question is central to advancing our understanding of migratory flight strategies and requires the integration of information across levels of biological organisation, e.g.

Seasonal associations with novel climates for North American migratory bird populations.

Determining the implications of global climate change for highly mobile taxa such as migratory birds requires a perspective that is spatiotemporally comprehensive and ecologically relevant. Here, we document how passerine bird species that migrate within the Western Hemisphere (n = 77) are associated with projected novel climates across the full annual cycle. Following expectations, highly novel climates occurred on tropical non-breeding grounds and the least novel climates occurred on temperate breeding grounds.

Global change and the distributional dynamics of migratory bird populations wintering in Central America.

Understanding the susceptibility of highly mobile taxa such as migratory birds to global change requires information on geographic patterns of occurrence across the annual cycle. Neotropical migrants that breed in North America and winter in Central America occur in high concentrations on their non-breeding grounds where they spend the majority of the year and where habitat loss has been associated with population declines. Here, we use eBird data to model weekly patterns of abundance and occurrence for 21 forest passerine species that winter in Central America.

Seasonal associations with urban light pollution for nocturnally migrating bird populations.

The spatial extent and intensity of artificial light at night (ALAN) has increased worldwide through the growth of urban environments. There is evidence that nocturnally migrating birds are attracted to ALAN, and there is evidence that nocturnally migrating bird populations are more likely to occur in urban areas during migration, especially in the autumn. Here, we test if urban sources of ALAN are responsible, at least in part, for these observed urban associations.

Projected changes in prevailing winds for transatlantic migratory birds under global warming.

A number of terrestrial bird species that breed in North America cross the Atlantic Ocean during autumn migration when travelling to their non-breeding grounds in the Caribbean or South America. When conducting oceanic crossings, migratory birds tend to associate with mild or supportive winds, whose speed and direction may change under global warming. The implications of these changes for transoceanic migratory bird populations have not been addressed.