Weather conditions and date influence male Sage Grouse attendance rates at leks

Fremgen, Aleshia L.; Hansen, Christopher P.; Rumble, Mark A.; Gamo, R. Scott; Millspaugh, Joshua J.

doi:10.1111/ibi.12598

Cited by 16 publications

(21 citation statements)

References 67 publications

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“…Longer-term surveys using acoustic methods could provide an alternative data source where lek counts are not possible, or potentially allow calibration between lek counts undertaken at different sites on different days (Sadoti et al 2016). This would help to address variation in lek attendance through the season (Sadoti et al 2016;Fremgen et al 2018). In addition, bioacoustics offers a non-intrusive survey method in comparison to other techniques such as lek counts, GPS/ radio tagging and use of dogs.…”

Section: Resultsmentioning

confidence: 99%

“…However, this does not appear to be true over shorter time frames, due to the considerable daily variation in call activity. This variation is likely the result of factors such as the date within the lekking season, and weather conditions affecting bird behaviour-factors that could also affect lek counts, and which are perhaps not considered fully within that method at the current time (Raynor et al 2017;Fremgen et al 2018). In addition, the mobility of Capercaillie around the lek site, with birds potentially displaying from different places on different mornings, may affect their detectability on a day-to-day basis, and adverse weather conditions (i.e.…”

Section: Capercaillie Call Activity Is Related To Lek Count Numbersmentioning

confidence: 99%

“…The age and sex biases of lek counts are well recognized (Storch 1997;Mollet et al 2015). In addition, there are a number of temporal and environmental conditions that can affect detectability and occupancy at leks (Walsh et al 2004;Raynor et al 2017;Fremgen et al 2018). An understanding of these factors is critical to improving population estimates for the species being monitored (Drummer et al 2011;Sadoti et al 2016;Priyadarshani et al 2018).…”

Section: Capercaillie Call Activity Is Related To Temporal and Enviromentioning

confidence: 99%

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Comparison between lek counts and bioacoustic recording for monitoring Western Capercaillie (Tetrao urogallus L.)

Abrahams

2019

J Ornithol

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Bioacoustics is the study of animal sounds. The importance of bioacoustics for biological research and the survey and monitoring of bird populations is becoming increasingly recognized. This is particularly the case for the capture of long-term data on rare species that are prone to disturbance or are otherwise difficult to survey. The global population of the Western Capercaillie (Tetrao urogallus L.; hereafter 'Capercaillie') is declining, and its status in the UK is highly precarious. Current methods for monitoring this species are subject to a number of constraints that affect the quality of collected data. Bioacoustics could provide a useful complement to these existing methods, in particular for the assessment of activity at leks. This study used acoustic recorders to survey Capercaillie vocal activity for a month at ten lek sites, and quantified the numbers of calls produced. Traditional lek count surveys were undertaken at all sites during this time. The recorded vocal activity data (1) correlated with the number of birds recorded by human surveyors, (2) indicated that traditional surveys may be causing some disturbance at the lek sites, and (3) showed that call numbers are related to temporal and environmental variables. The bioacoustic approach can provide high-quality, long-term data, that can be effectively combined with the traditional lek survey technique. It should be utilized more frequently as a survey and monitoring tool to provide structured, coherent results that can be used to aid conservation efforts.

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Section: Resultsmentioning

confidence: 99%

Section: Capercaillie Call Activity Is Related To Lek Count Numbersmentioning

confidence: 99%

Section: Capercaillie Call Activity Is Related To Temporal and Enviromentioning

confidence: 99%

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Comparison between lek counts and bioacoustic recording for monitoring Western Capercaillie (Tetrao urogallus L.)

Abrahams

2019

J Ornithol

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“…For all of these reasons, lek counts have been widely used by resource agencies to monitor trends in sage-grouse populations across long terms and large scales (Walsh et al 2004, Connelly et al 2011, McCaffery et al 2016, and their potential for tracking population response to local-scale management may be high. There is a growing body of literature examining various aspects of lek counting methodology, including assessments of both field, e.g., male sightability, and sampling, e.g., repeated vs single count, considerations (Fedy and Aldridge 2011, Monroe et al 2016, Baumgardt et al 2017, Wann et al 2019 as well as the frequency of male lek attendance and its relevance to availability for detection (e.g., Blomberg et al 2013, Fremgen et al 2019, Wann et al 2019. However, these studies largely addressed sampling questions relevant to large-scale monitoring, such as statewide or subregions within a state, and there is comparably little research addressing sampling concerns surrounding local population monitoring at the relatively small scale of individual habitat treatments.…”

Section: Introductionmentioning

confidence: 99%

How many leks does it take? Minimum samples sizes for measuring local-scale conservation outcomes in Greater Sage-Grouse

Blomberg¹,

Hagen²

2020

ACE

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Monitoring population response to conservation actions, such as habitat management, is critical to evaluate conservation outcomes. Greater Sage-Grouse (Centrocercus urophasianus) has been the recipient of substantial recent conservation efforts in North America. Sage-Grouse are often surveyed using counts of males displaying on breeding leks, and these lek counts offer a practical method for monitoring Sage-Grouse population trends. Although substantial work has assessed the utility of lek count data for largescale population monitoring, there has been comparably little effort focused on the use of lek counts to evaluate local-scale management. We used Greater Sage-Grouse lek count data from Oregon, USA, combined with simulation, to evaluate the sample sizes (number of leks, years of monitoring) required to detect a positive outcome of habitat management on population growth. We further assessed assumptions associated with male detection, and compared analyses that both did (N-mixture models) and did not (Poisson regression) account for detection probability. We found that when treatments produced a 5% increase in annual population growth, and leks were monitored for at least 10 years, lek counts produced unbiased and detectable estimates of treatment effects with as few as seven treatment and seven control leks. Using an unbalanced design with a greater number of control leks (n = 16) permitted inference from even fewer treatment leks (n = 4), however, we found no scenarios where use of more control leks permitted detection of smaller treatment effects or allowed shorter duration studies. We found that N-mixture models and Poisson regression of the maximum of three repeated counts produced equivalent results when detection probability was constant, but at the small sample sizes we evaluated, confounding between detection probability and habitat management compromised the accuracy of all analysis methods. Our results show that lek counts hold promise for efficient monitoring of local-scale conservation, but further work is needed to understand the mechanisms that affect male detection during lek surveys. Combien de leks sont nécessaires? Taille d'échantillon minimum requise pour mesurer les retombées de conservation à l'échelle locale chez le Tétras des armoisesRÉSUMÉ. À la suite de l'instauration d'activités de conservation, telles que l'aménagement d'un habitat, le suivi des populations est essentiel afin qu'on puisse évaluer les retombées sur la conservation. Le Tétras des armoises (Centrocercus urophasianus) a fait l'objet d'efforts considérables récents de conservation en Amérique du Nord. Le dénombrement des mâles nicheurs qui paradent aux leks constitue une méthode d'inventaire fréquente chez le tétras, et ces comptes aux leks s'avèrent pratiques pour suivre les tendances de population. Bien qu'il y ait eu de nombreux travaux attestant de l'utilité des comptes aux leks pour le suivi de population à grande échelle, peu d'efforts ont ciblé l'utilisation de comptes aux leks pour évaluer la gestion à petite éc...

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“…Two components relate to the distribution and movement of individuals, including probability that a bird's home range overlaps the sampling unit (p s ; in the case of sage-grouse, attending a lek at least once in a season) and probability of presence at the sampling unit during the count (p p ). The other two components characterize the detection process for birds given their presence at the sampling unit: probability of being available for (Beck and Braun 1980, Emmons and Braun 1984, Walsh et al 2004, Fremgen et al 2019, Wann et al 2019. As a result, trends in sage-grouse populations are typically estimated using the maximum observed number of males from repeated counts each year at each lek (hereafter, peak counts; Connelly et al 2003).…”

Section: Introductionmentioning

confidence: 99%

The importance of simulation assumptions when evaluating detectability in population models

et al. 2019

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Population monitoring is important for investigating a variety of ecological questions, and N‐mixture models are increasingly used to model population size (N) and trends (λ) while estimating detectability (p) from repeated counts within primary periods (when populations are closed to changes). Extending these models to dynamic processes with serial dependence across primary periods may relax the closure assumption, but simulations to evaluate models and inform effort (e.g., number of repeated counts) typically assume p is constant or random across sites and years. Thus, it is unknown how these models perform under scenarios where trends in p confound inferences on N and λ, and conclusions regarding effort may be overoptimistic. Here, we used global positioning system data from greater sage‐grouse (Centrocercus urophasianus) to inform simulations of the detection process for lek counts of this species, and we created scenarios with and without linear annual trends in p. We then compared estimates of N and λ from hierarchical population models either fit with single maximum counts or with detectability estimated from repeated counts (dynamic N‐mixture models). We also explored using auxiliary data to correct counts for variation in detectability. Uncorrected count models consistently underestimated N by >50%, whereas N‐mixture models without auxiliary data underestimated N to a lesser degree due to unmodeled heterogeneity in p such as age. Nevertheless, estimates of λ from both types of models were unbiased and similar for scenarios without trends in p. When p declined systematically across years, uncorrected count models underestimated λ, whereas N‐mixture models estimated λ with little bias when all sites were counted repeatedly. Auxiliary data also reduced bias in parameter estimates. Evaluating population models using scenarios with systematic variation in p may better reveal potential biases and inform effort than simulations that assume p is constant or random. Dynamic N‐mixture models can distinguish between trends in p and N, but also require repeated counts within primary periods for accurate estimates. Auxiliary data may be useful when researchers lack repeated counts, wish to monitor more sites less intensively, or require unbiased estimates of N.

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Weather conditions and date influence male Sage Grouse attendance rates at leks

Cited by 16 publications

References 67 publications

Comparison between lek counts and bioacoustic recording for monitoring Western Capercaillie (Tetrao urogallus L.)

Comparison between lek counts and bioacoustic recording for monitoring Western Capercaillie (Tetrao urogallus L.)

How many leks does it take? Minimum samples sizes for measuring local-scale conservation outcomes in Greater Sage-Grouse

The importance of simulation assumptions when evaluating detectability in population models

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