Anthropogenic Illumination as Guiding Light for Nocturnal Bird Migrants Identified by Remote Sensing

Migrant birds rely on environmental and celestial cues for navigation and orientation during their journeys. Adverse weather, such as heavy rain or fog, but also thick layers of low-level clouds, affect visibility and can challenge birds’ ability to orientate. Therefore, birds typically favour certain meteorological conditions for migration. Photopollution from artificial lights outdoors and radiated from buildings is known to negatively affect nocturnal migrants’ flight behaviour and trajectories, which may lead to collisions with human infrastructure. Positive effects of artificial light have been identified in some stationary birds, e.g., for extended foraging hours, though not during migration. In the present study, we show the effect of artificial light on the concentration and flight directions of migrating birds during overcast conditions in the peri-urban woodland in Southern Finland. Overcast conditions, by low-level clouds, prompted birds to migrate at low altitudes. Instead of spatially homogenous large-scale migration patterns, birds were observed to adapt their flight directions, in accordance with the artificial lights of the urbanized area. By using dual- and single-polarisation weather radar data we were able to study small-scale patterns of bird movements under the influence of low-level cloud layers. These cases show the remarkable capability of the existing weather radar networks to study bird migration

Anthropogenic Illumination as Guiding Light for Nocturnal Bird Migrants Identified by Remote Sensing

Migrant birds rely on environmental and celestial cues for navigation and orientation during their journeys. Adverse weather, such as heavy rain or fog, but also thick layers of low-level clouds, affect visibility and can challenge birds’ ability to orientate. Therefore, birds typically favour certain meteorological conditions for migration. Photopollution from artificial lights outdoors and radiated from buildings is known to negatively affect nocturnal migrants’ flight behaviour and trajectories, which may lead to collisions with human infrastructure. Positive effects of artificial light have been identified in some stationary birds, e.g., for extended foraging hours, though not during migration. In the present study, we show the effect of artificial light on the concentration and flight directions of migrating birds during overcast conditions in the peri-urban woodland in Southern Finland. Overcast conditions, by low-level clouds, prompted birds to migrate at low altitudes. Instead of spatially homogenous large-scale migration patterns, birds were observed to adapt their flight directions, in accordance with the artificial lights of the urbanized area. By using dual- and single-polarisation weather radar data we were able to study small-scale patterns of bird movements under the influence of low-level cloud layers. These cases show the remarkable capability of the existing weather radar networks to study bird migration

Effects of a sea barrier on large-scale migration patterns studied by a network of weather radars

Capsule: Nocturnal passerine migration patterns were studied by a network of weather radars within the East-Atlantic flyway providing large-scale information on the effect of a geographical barrier. Aims: The aim of this study was to obtain a large-scale spatial overview of the effects of a sea barrier on migratory flyways in northern Spain/western France. Methods: Weather radar data were used from five sites at the Bay of Biscay during nights in spring 2015 to calculate flight directions and migration traffic rates (MTRs). Results: The highest MTRs were registered by the radars at the southeastern edge of the bay, with a gradual decrease northwards. Spring migration direction was generally NNE/NE. Continuous nocturnal migration pattern indicated migration over land in the south. The radar half way up the French coast exhibited bimodal migration intensities at night, indicating sea crossing, and the northernmost corner of the bay showed little migration. Conclusions: Radar patterns indicated migration over land and sea during spring migration. Sea crossing occurred with flight distances of up to about 500 km. Most migration activity was observed in the radars along the southeastern section of the bay, indicating that the general migration flyway from Spain funnels through the eastern side of the north Iberian Peninsula

Quantifying nocturnal thrush migration using sensor data fusion between acoustics and vertical-looking radar

Studying nocturnal bird migration is challenging because direct visual observations are difficult during darkness. Radar has been the means of choice to study nocturnal bird migration for several decades, but provides limited taxonomic information. Here, to ascertain the feasibility of enhancing the taxonomic resolution of radar data, we combined acoustic data with vertical-looking radar measurements to quantify thrush (Family: Turdidae) migration. Acoustic recordings, collected in Helsinki between August and October of 2021-2022, were used to identify likely nights of high and low thrush migration. Then, we built a random forest classifier that used recorded radar signals from those nights to separate all migrating passerines across the autumn migration season into thrushes and non-thrushes. The classifier had a high overall accuracy (approximate to 0.82), with wingbeat frequency and bird size being key for separation. The overall estimated thrush autumn migration phenology was in line with known migratory patterns and strongly correlated (Pearson correlation coefficient approximate to 0.65) with the phenology of the acoustic data. These results confirm how the joint application of acoustic and vertical-looking radar data can, under certain migratory conditions and locations, be used to quantify 'family-level' bird migration.This study addresses the challenge of studying nocturnal bird migration, typically hindered by limited taxonomic information from radar data. To enhance resolution, we combined acoustic recordings with vertical-looking radar measurements, focusing on thrush migration. Using a random forest classifier, we achieved a high accuracy in distinguishing thrushes from non-thrushes during autumn migration, relying on key factors like wingbeat frequency and bird size. The estimated thrush migration phenology aligned with known patterns and correlated strongly with acoustic data. Our study provides the first example of combining acoustic and radar data to extract taxonomic information, enabling the quantification of family-level migration from radar data. imag

Delayed Cerebral Ischemia Predicts Neurocognitive Impairment Following Aneurysmal Subarachnoid Hemorrhage

Prior studies have shown that the incidence of neuropsychological deficits (NPDs) after aneurysmal subarachnoid hemorrhage (aSAH) is high despite excellent outcome according to neurologic grading scales. Delayed cerebral ischemia (DCI) occurs in 30% of patients after aSAH and significantly contributes to the mortality and morbidity of aSAH. We tested the hypothesis that DCI is associated with neuropsychological outcome

Paracoccidioidomycosis: Cells expressing IL17 and Foxp3 in cutaneous and mucosal lesions

We demonstrated and quantified by immunohistochemistry the population of cells expressing IL17 and Foxp3 in cutaneous and mucosal paracoccidioidomycosis lesions, associating these populations of cells with different presentations of granulomatous response. For this purpose, 61 skin biopsies and 55 oral mucosal biopsies were evaluated. Cells expressing IL17 were distributed in the inflammatory infiltrate in both groups of lesions and were found in the vessels` wall too. Foxp3+ expression was limited to the nuclei of lymphocytes in the inflammatory infiltrate. The distribution of IL17 was similar among the groups; however, Foxp3+ cells were increased in mucosal lesions that displayed compact granulomas. The results suggest that IL17 seems to play a role in paracoccidioidomycosis cutaneous and mucosal lesions, probably as secondary cells in the clearance of the fungal antigens. The presence of Foxp3+ cells both in skin and mucosa corroborates some previous researches that suggest the role of this group of cells in the modulation of local immune response. (C) 2011 Elsevier Ltd. All rights reserved.FAPESP Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (Brazil)[2008/09355-8