Landbird Counting Techniques: Current Practices and an Alternative

Rosenstock, Steven S.; Anderson, David R.; Giesen, Kenneth M.; Leukering, Tony; Carter, Michael F.

doi:10.1642/0004-8038(2002)119[0046:lctcpa]2.0.co;2

Cited by 287 publications

(112 citation statements)

References 28 publications

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“…Indeed, most annual variations (e.g., weather) can be expected to play on several species and would then be tampered in the computation of frequency. Another bias may have been generated if there was a difference in species detectability between transects among fragments and point counts in the continuous landscape (Rosenstock et al 2002). To eliminate such possibility, we sampled 67 transects in the open landscape in 2007, to compare the differences in species abundances between the two methods.…”

Section: Methodological Limitationsmentioning

confidence: 99%

Area mediated shifts in bird community composition: a study on a fragmented Mediterranean grassland

Caplat

Fonderflick

2009

Biodivers Conserv

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The effects of habitat fragmentation on birds have often been studied in forest specialist species. Here we aimed at comparing the response of open habitat birds within a range of habitat specialization. The study area was a Mediterranean pseudo-steppe, designated as important for conservation yet fragmented by tree encroachment. We defined bird species dependency on steppe-like habitat by a correspondence analysis, allowing us to distinguish between specialists, generalists and scrubland species. We studied species abundance in relation to fragment area, testing whether species representation in fragments differed from those in continuous habitat. This analysis showed a contrasted response to fragment size between ''open habitat'' specialist species and generalist ones. Open habitat species were under-represented in the smallest fragments, while generalist were overrepresented in small fragments in comparison to their distribution in continuous habitats. We discuss how these results can be linked to species habitat requirements. We find that scrubland species seem to be favoured by encroachment of woody vegetation, as they are able to explore and use the wooded matrix; however specialist species are restricted to open patches and are sensitive to a reduction in patch size. This allows us to predict how different species can exhibit a different sensitivity to habitat fragmentation.

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Section: Methodological Limitationsmentioning

confidence: 99%

Area mediated shifts in bird community composition: a study on a fragmented Mediterranean grassland

Caplat

Fonderflick

2009

Biodivers Conserv

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“…First, it is common practice to ignore detection probability (e.g. Rosenstock et al 2002;EuMon consortium 2006;Henry and Jarne 2007). This practice may be reasonable if a pre-analysis showed that detection probability can be considered constant trough space and time, or that variation is random and cannot generate spurious trends.…”

Section: Accounting For Measurement Errormentioning

confidence: 99%

Integrating ongoing biodiversity monitoring: potential benefits and methods

et al. 2008

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Halting the loss of biodiversity comes along with the need to quantify biodiversity composition and dynamics at large spatial and temporal scales. Highly standardized, international monitoring networks would be ideal, but they do not exist yet. If we are to assess changes in biodiversity now, combining output available from ongoing monitoring initiatives is the only option. However, integration of biodiversity information across schemes is still very poorly developed. In this paper, we outline practical issues to be considered when planning to combine existing monitoring information. First, we provide an overview of avenues for integration along the four dimensions that characterize a monitoring design: sample size, biological coverage, spatial coverage and temporal coverage. We also emphasize that complementarity in monitoring targets across schemes enables to describe complex processes of biodiversity dynamics, e.g. through relating species traits to the impacts of environmental changes. Second, we review some methods to overcome differences in designs among monitoring schemes, such as site selection, poststratification and measurement error. Finally, we point out some commonly used statistical methods that are at hand for combining data or parameter estimates. We especially emphasize the possible levels of data integration (raw data, parameter estimates, or effect size estimates), and the largely under-exploited potential of meta-analysis methods and weighted analyses. This contribution aims to bolster the practice and use of integration of ongoing monitoring initiatives for biodiversity assessment.

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“…The point count method (Blondel et al 1970;Bibby et al 2000) is one of the most widely used methods for taking censuses of bird populations (Rosenstock et al 2002;Simons et al 2009). A point count is defined as a period of time during which an observer records the auditory and visual signals of the individuals on predetermined sites.…”

Section: Introductionmentioning

confidence: 99%

“…In order to resolve this problem, in part, standardized methods are generally used to perform point counts (Rosenstock et al 2002): low wind levels and rainfall, calibration of observers, and surveys carried out early in the morning when the birds' singing activity is at its most intense. The environmental conditions at the time of point counts are therefore quite similar from one study to another.…”

Section: Introductionmentioning

confidence: 99%

Point count duration: five minutes are usually sufficient to model the distribution of bird species and to study the structure of communities for a French landscape

Bonthoux

Balent

2011

J Ornithol

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The point count method is very widely used for estimating bird abundances. In studies of bird-environment relationships, the duration used for point counts varies considerably from one study to another. Short counting times may increase the number of false absences while long counting times increase the probability that birds initially absent immigrate during the counting period. This study aims to quantify the effect of point count duration on the performance of bird distribution models and on the estimated structure of the communities. We used a sample of 256 point counts collected in south western France and we compared four count durations (5, 10, 15 and 20 min). After comparing the predictive performance of seven statistical methods, we constructed one GAM (generalized additive model) per counting time to link the presenceabsence data of each species with seven landscape variables. We evaluated the models by examining explained deviance and by comparing predicted and observed values for an independent data using AUC (area under the curve) and TSS (true skill statistics). At the community level, we constructed one CQO (constrained quadratic ordination) per counting time, then we compared the species' scores along the latent environmental variables. For the 21 species studied, the overall performance of GAMs only improves very moderately with a lengthening of the counting time (mean D 2 = 25% for 5 min and 28% for 20 min; mean TSS = 0.40 for 5 min and 0.43 for 20 min), with an increase for some species and a decrease for others. The latent environmental variables of the four CQOs were associated with the same explanatory variables and the scores of the species along the latent variables were highly correlated (between 5 and 20 min, P \ 2.10 -16 , rho = 0.99). In the perspective of building reliable bird distribution models, our results thus show that a point count duration of 5 min is sufficient in temperate regions such as France.

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Landbird Counting Techniques: Current Practices and an Alternative

Cited by 287 publications

References 28 publications

Area mediated shifts in bird community composition: a study on a fragmented Mediterranean grassland

Area mediated shifts in bird community composition: a study on a fragmented Mediterranean grassland

Integrating ongoing biodiversity monitoring: potential benefits and methods

Point count duration: five minutes are usually sufficient to model the distribution of bird species and to study the structure of communities for a French landscape

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