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Author (up) Bolshakov, C.V.; Bulyuk, V.N.; Sinelschikova, A.Y.; Vorotkov, M.V.
Title Influence of the vertical light beam on numbers and flight trajectories of night-migrating songbirds Type Journal Article
Year 2013 Publication Avian Ecol. Behav. Abbreviated Journal
Volume 24 Issue Pages 35–49
Keywords Animals; nocturnal migration; light pollution; numbers; flight track; extrinsic factors
Abstract In this paper we analyse the data obtained in the automatic regime by the Optical Electronic Device (OED, Vorotkov et al. 2009; Bolshakov et al. 2010) for autumn nocturnal passage of passerines on the Courish Spit on the Baltic Sea and estimate: (1) numbers aloft under differ- ent types of wind (following wind, opposing wind and calm conditions); (2) flight trajectories in the 5° cone of white light. We found that under natural nocturnal illumination conditions, the vertical cone of white light impacts the detectable numbers aloft and disturbs straight flight trajectories. The OED data obtained throughout the night suggest, after correction for ground speed and the mean flight altitude, the actual number of birds in the light cone peaks at calm conditions, is halved under following winds which are optimal for passage and is 21 times lower under unfavourable headwinds. It is assumed that high numbers in the light cone under calm conditions is an artefact of bird attraction by light and their concentration around the searchlights. The OED data obtained for midnight ±1 hour, flying migrants respond to the vertical light cone under all types of wind conditions by altering their straight flight trajec- tories. However, this response is most apparent in still air conditions. The proportion of birds that change their flight track reaches 43%. We assume that under such conditions some birds are not only attracted to the illuminated zone at low altitudes, but, besides slowing down their ground speed, change their trajectories to the degree of flying in circles. To determine combi- nations of factors and to test for their possible impact on the probability of response to light, we used a binary logistic regression. The presence of birds with straight vs. curved tracks was used as the dependent variable. Final logistic models obtained for midnight ±1 hour for calm conditions and headwinds, suggest that occurrence probability of songbirds with curvilinear flight tracks is higher for small birds, when no or just a small part of Moon disk is visible and under high air humidity. Under headwinds the probability of occurrence of birds flying curvi- linear tracks is also higher under overcast. For following winds, the probability of occurrence birds flying curvilinearly was higher when many small birds were aloft, when air humidity was high and when wind was not strictly following. Unlike other wind situations, this model did not include the size of visible part of the Moon disk as a significant factor. The increase of occurrence of curvilinear flight tracks through the light beam when winds were not exactly following was probably caused by the problems with compensating the lateral component of tailwinds under high velocities, especially by small birds.
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Call Number LoNNe @ christopher.kyba @ Serial 378
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Author (up) Mavraki, N.; Georgiadis, M.; Koutsikopoulos, C.; Tzanatos, E.
Title Unravelling the nocturnal appearance of bogue Boops boops shoals in the anthropogenically modified shallow littoral Type Journal Article
Year 2016 Publication Journal of Fish Biology Abbreviated Journal J Fish Biol
Volume Issue Pages
Keywords Animals; artificial habitats; coastal zone; fish behaviour; nocturnal migration; predation avoidance; Boops boops; fish
Abstract In the present study the role of the nocturnal migration of bogue Boops boops shoals to anthropogenically modified shallow littoral locations was examined, evaluating four alternative hypotheses: (1) feeding, (2) reproduction, (3) attraction of B. boops to artificial light and (4) concealment in the darkness related to predation avoidance. All hypotheses apart from predation avoidance were rejected, as B. boops tended to concentrate in shaded locations of wider illuminated areas, a finding not only important concerning fish behaviour, but also with significant management implications.
Address Section of Animal Biology, Department of Biology, University of Patras, GR 26504 Rio, Patras, Greece; ninon.mavraki(at)gmail.com
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Publisher FSBI Place of Publication Editor
Language English Summary Language English Original Title
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ISSN 0022-1112 ISBN Medium
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Notes PMID:27094613 Approved no
Call Number IDA @ john @ Serial 1447
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Author (up) Van Doren, B.; Horton, K.G.; Dokter, A.M.; Klinck, H.; Elbin, S.B., Farnsworth, A.; Dokter, A.M; Klinck, H.; Elbin, S.B.; Farnsworth, A.
Title High-intensity urban light installation dramatically alters nocturnal bird migration Type Journal Article
Year 2017 Publication Publications of the National Academy of Sciences Abbreviated Journal PNAS
Volume 114 Issue 42 Pages 11175-11180
Keywords Animals; artificial light; nocturnal migration; remote sensing; radar; ornithology; flight calls
Abstract 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.
Address Information Science Program, Cornell Lab of Ornithology, Ithaca, NY 14850 USA; af27{at}cornell.edu
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Publisher PNAS Place of Publication Editor
Language English Summary Language English Original Title
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ISSN 1091-6490 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 1741
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