https://ir.library.oregonstate.edu/downloads/1831cm56h

The eBird enterprise: An integrated approach to development and application of citizen science

Billions of nocturnally migrating birds move through increasingly photopolluted skies, relying on cues for navigation and orientation that artificial light at night (ALAN) can impair. However, no studies have quantified avian responses to powerful ground-based light sources in urban areas. We studied effects of ALAN on migrating birds by monitoring the beams of the National September 11 Memorial & Museum's "Tribute in Light" in New York, quantifying behavioral responses with radar and acoustic sensors and modeling disorientation and attraction with simulations. This single light source induced significant behavioral alterations in birds, even in good visibility conditions, in this heavily photopolluted environment, and to altitudes up to 4 km. We estimate that the installation influenced ≈1.1 million birds during our study period of 7 d over 7 y. When the installation was illuminated, birds aggregated in high densities, decreased flight speeds, followed circular flight paths, and vocalized frequently. Simulations revealed a high probability of disorientation and subsequent attraction for nearby birds, and bird densities near the installation exceeded magnitudes 20 times greater than surrounding baseline densities during each year's observations. However, behavioral disruptions disappeared when lights were extinguished, suggesting that selective removal of light during nights with substantial bird migration is a viable strategy for minimizing potentially fatal interactions among ALAN, structures, and birds. Our results also highlight the value of additional studies describing behavioral patterns of nocturnally migrating birds in powerful lights in urban areas as well as conservation implications for such lighting installations.

https://www.pnas.org/content/pnas/114/42/11175.full.pdf

High-intensity urban light installation dramatically alters nocturnal bird migration

Billions of animals cross the globe each year during seasonal migrations, but efforts to monitor them are hampered by the unpredictability of their movements. We developed a bird migration forecast system at a continental scale by leveraging 23 years of spring observations to identify associations between atmospheric conditions and bird migration intensity. Our models explained up to 81% of variation in migration intensity across the United States at altitudes of 0 to 3000 meters, and performance remained high in forecasting events 1 to 7 days in advance (62 to 76% of variation was explained). Avian migratory movements across the United States likely exceed 500 million individuals per night during peak passage. Bird migration forecasts will reduce collisions with buildings, airplanes, and wind turbines; inform a variety of monitoring efforts; and engage the public.

A continental system for forecasting bird migration

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 Neotropical migrants apparently achieved higher survival during the combined migration and non-breeding period, despite an average three- to fourfold longer migration distance, compared with a more northern assemblage of mostly temperate-wintering migrants Additional mortality expected with longer migration distances was probably offset by high survival in the (sub)tropics Nearctic-Neotropical migrants relying on a 'higher survivorship' life-history strategy may be particularly sensitive to variations in survival on the overwintering grounds, highlighting the need to identify and conserve important non-breeding habitats

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

Nocturnal avian migration flyways remain an elusive concept, as we have largely lacked methods to map their full extent We used the network of European weather radars to investigate nocturnal bird movements at the scale of the European flyway We mapped the main migration directions and showed the intensity of movement across part of Europe by extracting biological information from 70 weather radar stations from northern Scandinavia to Portugal, during the autumn migration season of 2016 On average, over the 20 nights and all sites, 389 birds passed per 1 km transect per hour The night with highest migration intensity showed an average of 1621 birds km–1 h–1 passing the radar stations, but there was considerable geographical and temporal variation in migration intensity The highest intensity of migration was seen in central France The overall migration directions showed strong southwest components Migration dynamics were strongly related to synoptic wind conditions A wind-related mass migration event occurred immediately after a change in wind conditions, but quickly diminished even when supporting winds continued to prevail This first continental-scale study using the European network of weather radars demonstrates the wealth of information available and its potential for investigating large-scale bird movements, with consequences for ecosystem function, nutrient transfer, human and livestock health, and civil and military aviation

https://onlinelibrary.wiley.com/doi/pdf/10.1111/ecog.04003

Revealing patterns of nocturnal migration using the European weather radar network

Archived data from the WSR-88D network of weather radars in the US hold detailed information about the continent-scale migratory movements of birds over the last 20 years. However, significant technical challenges must be overcome to understand this information and harness its potential for science and conservation. We present an approximate Bayesian inference algorithm to reconstruct the velocity fields of birds migrating in the vicinity of a radar station. This is part of a larger project to quantify bird migration at large scales using weather radar data.

/pdf/approximate-bayesian-inference-for-reconstructing-velocities-42is5tc1ai.pdf

Approximate Bayesian inference for reconstructing velocities of migrating birds from weather radar

Bird migration occurs at the largest of global scales, but monitoring such movements can be challenging. In the US there is an operational network of weather radars providing freely accessible data for monitoring meteorological phenomena in the atmosphere. Individual radars are sensitive enough to detect birds, and can provide insight into migratory behaviors of birds at scales that are not possible using other sensors. Archived data from the WSR-88D network of US weather radars hold valuable and detailed information about the continent-scale migratory movements of birds over the last 20 years. However, significant technical challenges must be overcome to understand this information and harness its potential for science and conservation. We describe recent work on an AI system to quantify bird migration using radar data, which is part of the larger BirdCast project to model and forecast bird migration at large scales using radar, weather, and citizen science data.

https://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/52353/DietterichThomasElectricalEngineeringComputerScienceReconstructingVelocitiesMigrating.pdf?sequence=1

Kevin F. Webb

Papers

Approximate Bayesian inference for reconstructing velocities of migrating birds from weather radar

Reconstructing Velocities of Migrating Birds from Weather Radar – A Case Study in Computational Sustainability