Perceptibility of Prairie Songbirds Using Double-Observer Point Counts

Leston, Lionel; Koper, Nicola; Rosa, Patrícia da

doi:10.1353/gpr.2015.0021

Cited by 19 publications

(17 citation statements)

References 37 publications

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“…This pattern is consistent with our observations because the PCTD detection probability estimate for Horned Larks, a species reported to have low perceptibility (Leston et al. ), was the lowest and most variable for all species across both methods. In contrast, species reported to have high perceptibility either because of singing behavior, such as Vesper Sparrows and Western Meadowlarks (Leston et al.…”

Section: Discussionsupporting

confidence: 92%

“…Low perceptibility may introduce variation, which could increase the difference observed between the two methods. This pattern is consistent with our observations because the PCTD detection probability estimate for Horned Larks, a species reported to have low perceptibility (Leston et al 2015), was the lowest and most variable for all species across both methods. In contrast, species reported to have high perceptibility either because of singing behavior, such as Vesper Sparrows and Western Meadowlarks (Leston et al 2015), or because they form loose flocks during the breeding season, McCown's Longspurs (With 2010), had smaller differences in detection probability between the two methods.…”

Section: -231supporting

confidence: 91%

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Comparison of removal-based methods for estimating abundance of five species of prairie songbirds

Golding

Dreitz

2016

J. Field Ornithol.

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Estimating species abundance is important for land managers, especially for monitoring conservation efforts. The two main survey methods for estimating avian abundance are point counts and transects. Previous comparisons of these two methods have either been limited to a single species or have not included detection probability. During the 2012 breeding season, we compared and assessed the efficiency (precision for amount of effort) of point count time of detection (PCTD) and dependent double‐observer transect (TRMO) methods based on detection probabilities and abundance estimates of five species of songbirds that use a range of habitats in a prairie system in Montana dominated by sagebrush and grassland vegetation. Our focal species included Vesper Sparrows (Pooecetes gramineus), a generalist species found in both shrub and grassland habitat, shrub‐obligate Brewer's Sparrows (Spizella breweri), and McCown's Longspurs (Rhynchophanes mccownii), Horned Larks (Eremophila alpestris), and Western Meadowlarks (Sturnella neglecta), three species of grassland obligates that prefer different grass heights. Detection probabilities were significantly higher for TRMO surveys, with less variation for all five species and differences most pronounced for Brewer's Sparrows and Horned Larks. PCTD surveys required less field effort (~8–20 fewer people minutes per plot) than TRMO surveys because the TRMO surveys required two people. However, time spent on TRMO surveys provided between 0.38 and 87 times more precision per people minute than PCTD surveys. Our results suggest that TRMO surveys provide a more efficient (measured as time spent per unit of standard error) field‐based technique in sagebrush prairie systems for the species we investigated, resulting in more precise detection and abundance estimates.

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Section: Discussionsupporting

confidence: 92%

Section: -231supporting

confidence: 91%

Comparison of removal-based methods for estimating abundance of five species of prairie songbirds

Golding

Dreitz

2016

J. Field Ornithol.

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“…Unfortunately, other methods for compensating for imperfect detectability are also problematic in grassland ecosystems (Leston et al. ). Assumptions of population closure for removal sampling are violated when birds move during surveys (Farnsworth et al.…”

Section: Discussionmentioning

confidence: 99%

Effects of ambient noise on detectability and localization of avian songs and tones by observers in grasslands

Koper

Leston

Baker

et al. 2015

Ecology and Evolution

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Probability of detection and accuracy of distance estimates in aural avian surveys may be affected by the presence of anthropogenic noise, and this may lead to inaccurate evaluations of the effects of noisy infrastructure on wildlife. We used arrays of speakers broadcasting recordings of grassland bird songs and pure tones to assess the probability of detection, and localization accuracy, by observers at sites with and without noisy oil and gas infrastructure in south‐central Alberta from 2012 to 2014. Probability of detection varied with species and with speaker distance from transect line, but there were few effects of noisy infrastructure. Accuracy of distance estimates for songs and tones decreased as distance to observer increased, and distance estimation error was higher for tones at sites with infrastructure noise. Our results suggest that quiet to moderately loud anthropogenic noise may not mask detection of bird songs; however, errors in distance estimates during aural surveys may lead to inaccurate estimates of avian densities calculated using distance sampling. We recommend caution when applying distance sampling if most birds are unseen, and where ambient noise varies among treatments.

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“…This information is then used to estimate species-specific detection probabilities that are used to adjust estimated abundances for imperfect detection. Low detection is less of an issue for highly vocal species, such as Western Meadowlark, but can lead to underestimation of density in species that sing from the ground, such as the Grasshopper Sparrow (Leston et al 2015).…”

Section: Abundance Modelingmentioning

confidence: 99%

Quantifying avian relative abundance and ecosystem service value to identify conservation opportunities in the Midwestern U.S.

Wilsey¹,

Jensen²,

Miller³

2016

ACE

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ABSTRACT. Grassland birds are highly imperiled because of historical habitat loss and ongoing conversion of grasslands to agricultural and urban land uses. Therefore, prioritizing and further justifying conservation action in remaining grasslands is critical to protecting what remains. Grassland bird conservation has focused on identifying and protecting large grassland complexes referred to as Grassland Bird Conservation Areas (GBCAs). We identified and classified GBCAs in a region highly impacted by both agricultural and urban land conversion using previously developed methods. Then, we extended the analysis to include estimated relative abundance of five grassland focal species in each GBCA. Models of relative abundance were built using eight years of monitoring data collected by citizen scientists. Finally, we quantified the value of ecosystem services provided by each GBCA. There were nearly 55,000 ha of grassland habitats in the Chicago Metropolitan Region that met GBCA criteria, 33% (18,415 ha) of which were protected. Proportion of abundance in protected versus unprotected areas was similar for Bobolink (Dolichonyx oryzivorus; 46%), Grasshopper Sparrow (Ammodramus savannarum; 52%), and Sedge Wren (Cistothorus platensis; 48%), whereas, Henslow's Sparrow (Ammodramus henslowii; 75%) had a higher proportion of relative abundance in protected GBCAs and Eastern Meadowlark (Sturnella magna) had lower proportions (37%). GBCAs provisioned just under $900 million annually in ecosystem services, 73% of which is because of flood control. Outputs of this comprehensive approach will inform grassland bird conservation by providing detailed information about the value for birds and people of grassland habitats.Utilisation de la mesure de l'abondance relative aviaire et de la valeur des écoservices pour déterminer les occasions de conservation dans le Midwest étasunien RÉSUMÉ. Les oiseaux de prairie sont grandement menacés en raison des pertes d'habitat subies dans le passé et de la conversion continuelle des prairies à des fins d'agriculture ou d'urbanisation. Ainsi, la priorisation et la justification des mesures de conservation des prairies restantes sont critiques si on veut les protéger. Les mesures actuelles de conservation des oiseaux de prairie reposent surtout sur l'identification et la protection de vastes complexes de prairies, aussi nommés Grassland Bird Conservation Areas (GBCA). Nous avons identifié et classé les GBCA d'une région fortement touchée par la conversion des terres à des fins d'agriculture et d'urbanisation au moyen de méthodes élaborées précédemment. Nous avons ensuite élargi l'analyse pour inclure l'abondance relative de cinq espèces d'oiseaux de prairie estimée dans chaque GBCA. Les modèles d'abondance relative ont été construits à partir de huit années de données récoltées par des citoyens participant à des projets scientifiques. Finalement, nous avons mesuré la valeur des écoservices rendus par chaque GBCA. Près de 55 000 ha de milieux de prairie dans la région métropolitaine de Chicago cor...

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Perceptibility of Prairie Songbirds Using Double-Observer Point Counts

Cited by 19 publications

References 37 publications

Comparison of removal-based methods for estimating abundance of five species of prairie songbirds

Comparison of removal-based methods for estimating abundance of five species of prairie songbirds

Effects of ambient noise on detectability and localization of avian songs and tones by observers in grasslands

Quantifying avian relative abundance and ecosystem service value to identify conservation opportunities in the Midwestern U.S.

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