Beobachtung des nächtlichen Vogelzuges in Mauretanien

Liechti, Félix; Peter, Dieter; Komenda-Zehnder, Susanna

doi:10.1007/bf02465507

Cited by 8 publications

(11 citation statements)

References 10 publications

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“…We could even detect subtle wingbeats of large‐bodied ducks at short range (i.e., 400 m). Based on these findings and those of others, thermal infrared cameras have great potential as a tool for learning about nocturnally migrating birds (Liechti et al 1995, 2003 Fortin et al 1999, Zehnder et al 2002, Desholm et al 2006, Huppop et al 2006, Gauthreaux and Livingston 2006).…”

Section: Discussionmentioning

confidence: 68%

Waterfowl on weather radar: applying ground-truth to classify and quantify bird movements

O’Neal

Stafford²,

Larkin

2010

Journal of Field Ornithology

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Local and migratory movements aloft have important implications for the ecology and conservation of birds, but are difficult to quantify. Weather surveillance radar (WSR) offers a unique tool for observing movements of birds, but until now has been used primarily to address broad taxonomic questions. Herein, we demonstrate how natural history information and ground-truthing can be used to answer quantitative and taxon-specific questions regarding bird movements on WSR. We found that super-resolution Level II data from the National Oceanic and Atmospheric Administration's mass storage system was the most effective format and source of WSR data, and that several software packages were needed for thorough analysis of WSR data. Using WSR, we identified potential movements of birds emigrating from a waterfowl stopover area in Illinois in fall (1 September-31 December) 2006 and 2007. We compared spatial and temporal patterns of these movements to the natural history of taxa occupying the source habitat and classified these radar targets as dabbling ducks (tribe Anatini). A portable X-band radar measured the cruising heights of ducks at 400-600 m. During fall 2008, we conducted ground-truthing with a thermal infrared camera to enumerate birds passing over our field site during nocturnal migration events. This estimate of bird density, paired with an associated sample of WSR echo strength, provided a mean radar cross section the same as dabbling ducks (112.5 cm 2 ) and supported our natural-historybased classification. Thermal infrared-estimated duck densities explained most of the variation (R 2 = 0.91) in WSR echo strength across seven migration events of varying intensities, suggesting that radar cross sections of dabbling ducks and WSR reflectivity can be used to estimate duck numbers in other comparable contexts. Our results suggest that careful investigation of the spatial and temporal patterns of movements on radar, along with field-based ground-truthing, can be used to study and quantify the movements of specific bird taxa.

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Section: Discussionmentioning

confidence: 68%

Waterfowl on weather radar: applying ground-truth to classify and quantify bird movements

O’Neal

Stafford²,

Larkin

2010

Journal of Field Ornithology

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“…Environmental factors are often overlooked in calibration studies, e.g. omitted entirely in Liechti, Bruderer & Paproth (1995) and Liechti et al (2019) or addressed marginally in Nilsson, , and only rarely in a thorough manner (e.g. Weisshaupt et al, 2017).…”

Section: Discussionmentioning

confidence: 99%

“…As put forward in previous studies ( e.g . Liechti, Bruderer & Paproth 1995; Weisshaupt et al., 2017), the nominal beam width may deviate from the actual operational beam width, which, as a variable in the MTR equation, affects quantification. Also in the present comparison, this discrepancy between the nominal and actual beam width likely plays a decisive role in the dissimilarity of the absolute MTR estimates.…”

Section: Discussionmentioning

confidence: 99%

Comparison of bird migration in a radar wind profiler and a dedicated bird radar

Weisshaupt

Hervo

Haest

2023

Remote Sens Ecol Conserv

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Various types of radar systems are increasingly being used to monitor aerial biodiversity. Each of these types has different detection capabilities and sensitivities to environmental conditions, which affect the quantity and quality of the measured objects of interest. Radar wind profilers have long been known to detect birds, but their use in ornithology has remained limited, largely because of biologists' unfamiliarity with these systems. Although the potential of radar wind profilers for quantitative bird monitoring has been illustrated with time series of raw data, a comparison with a similar radar system more established in biology is missing. Here, we compare nocturnal bird migration patterns observed by a radar wind profiler during October 2019 and April 2021 with those from a dedicated bird radar BirdScan MR1. The systems were located 50 km apart with an altitudinal difference of about 850 m. The nightly migration intensities measured with both systems were highly correlated in both spring and autumn (Pearson correlation coefficient ≈ 0.8, P < 0.001), but estimated traffic measured by the radar wind profiler was on average five times higher in spring and nine times higher in autumn. Low ratios of the migration traffic rates of the Birdscan MR1 to those of the radar wind profiler occurred primarily in clear conditions. In both radar systems, migration occurred at significantly higher altitudes in spring than in autumn. Discrepancies in absolute numbers between both systems are likely due to both system‐inherent and external environmental and topographical factors, but also different quantification approaches. These findings support the capacity of radar wind profilers for aerial biomonitoring, independent of environmental conditions, and open up further avenues for studying the impact of weather on bird migration at detailed temporal and altitudinal scales.

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“…This thermal camera operated at short wave lengths (3-5 lm) at 60 fps, and had a detector array consisting of 512 3 512 pixels, and with a 50-mm, F 1.2 infrared lens, provided a 148 3 118 field of view. With this system, flight patterns of bats could be distinguished at a distance of 100 m. Liechti et al (1995) used a long-range thermal imaging unit (Long Range Infrared System, IRTV-445L; Inframetrics, Nashua, NH) with a 1.458 telephoto lens and were able to detect nearly 100% of all small passerines within the field of view at a distance of 3,000 m. The same unit was used in Sweden to monitor autumn bird migration Karlsson 2001, Zehnder et al 2001) and in Africa, on the edge of the Sahara desert, to study nocturnal bird migration (Liechti et al 2003). Gauthreaux and Livingston (2006) used a thermal imager (Radiance 1; Amber Raytheon, Goleta, CA) to study nocturnal migration at Pendleton, South Carolina, and Wallops Island, Virginia, USA, when weather conditions (no rain and relatively clear skies) allowed data collection.…”

Section: Visual Methods For Monitoring Nocturnal Activitymentioning

confidence: 99%

Assessing Impacts of Wind‐Energy Development on Nocturnally Active Birds and Bats: A Guidance Document

et al. 2007

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Our purpose is to provide researchers, consultants, decision‐makers, and other stakeholders with guidance to methods and metrics for investigating nocturnally active birds and bats in relation to utility‐scale wind‐energy development. The primary objectives of such studies are to 1) assess potential impacts on resident and migratory species, 2) quantify fatality rates on resident and migratory populations, 3) determine the causes of bird and bat fatalities, and 4) develop, assess, and implement methods for reducing risks to bird and bat populations and their habitats. We describe methods and tools and their uses, discuss limitations, assumptions, and data interpretation, present case studies and examples, and offer suggestions for improving studies on nocturnally active birds and bats in relation to wind‐energy development. We suggest best practices for research and monitoring studies using selected methods and metrics, but this is not intended as cookbook. We caution that each proposed and executed study will be different, and that decisions about which methods and metrics to use will depend upon several considerations, including study objectives, expected and realized risks to bird and bat populations, as well as budgetary and logistical considerations. Developed to complement and extend the existing National Wind Coordinating Committee document “Methods and Metrics for Assessing Impacts of Wind Energy Facilities on Wildlife” (Anderson et al. 1999), we provide information that stakeholders can use to aid in evaluating potential and actual impacts of wind power development on nocturnally active birds and bats. We hope that decision‐makers will find these guidelines helpful as they assemble information needed to support the permitting process, and that the public will use this guidance document as they participate in the permitting processes. We further hope that the wind industry will find valuable guidance from this document when 1) complying with data requirements as a part of the permitting process, 2) evaluating sites for potential development, 3) assessing impacts of operational wind‐energy facilities, and 4) mitigating local and cumulative impacts on nocturnally active birds and bats.

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Beobachtung des nächtlichen Vogelzuges in Mauretanien

Cited by 8 publications

References 10 publications

Waterfowl on weather radar: applying ground-truth to classify and quantify bird movements

Waterfowl on weather radar: applying ground-truth to classify and quantify bird movements

Comparison of bird migration in a radar wind profiler and a dedicated bird radar

Assessing Impacts of Wind‐Energy Development on Nocturnally Active Birds and Bats: A Guidance Document

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