The size of the Scottish population of Capercaillie<i>Tetrao urogallus</i>: results of the fourth national survey

Ewing, Steven R.; Eaton, Mark A.; Poole, Timothy F.; Davies, Megan; Haysom, Susan

doi:10.1080/00063657.2011.652937

Cited by 13 publications

(18 citation statements)

References 28 publications

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“…Jacob et al 2010), counts of displaying males at leks in spring are used to assess breeding population status and abundance for Capercaillie, for regional/national monitoring programmes (Picozzi et al 1992;Pollo et al 2005;Summers et al 2010). In Scotland, these showed a decline in numbers of 29% between 2004 and 2010 (Ewing et al 2012), although figures from 2010 to 2016 showed modest between-year fluctuations, with no significant overall trend (Wilkinson et al 2018).…”

Section: Introductionmentioning

confidence: 99%

“…Although lek counting is one of the few ways to gain regular population data on this elusive species, there are a number of recognized problems with this method. Firstly, Capercaillies are known to be susceptible to human disturbance (Ewing et al 2012;Mollet et al 2015), and regular impacts due to traditional counts could potentially have a negative effect on local populations. Surveys normally attempt to limit this disturbance by using trained surveyors and employing hides while at the lek site (Haysom 2013).…”

Section: Introductionmentioning

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: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Abrahams

2019

J Ornithol

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“…Thought to have become extinct in Scotland in the mid to late 18 th century, it was successfully reintroduced, but has declined again in the 20 th century. Whilst the reasons for this decline are complex and not fully understood, research has shown that low breeding success associated with climate change, and mortality resulting from adult birds flying into forest fences, have contributed to the decline (Moss 2001;Ewing et al 2012). The Scottish capercaillie population has been subject to concerted conservation management efforts over the past few decades, which appear to have stabilised the population at a critically low level , but not increased it (Wilkinson 2017), rendering it susceptible to extinction again in Britain (Moss 2001).…”

Section: Text Introductionmentioning

confidence: 99%

“…A range of methods have been used for capercaillie monitoring, including counts of displaying males at leks (Picozzi et al 1992;Summers et al 2010) and genetic capturerecapture techniques (Jacob et al 2010) to assess population status. For national status surveys in Scotland, line transects are conducted in winter (Ewing et al 2012). However, the species currently has a low population density and variable detectability relating to habitat type, sex and temperature (Ewing et al 2012).…”

Section: Text Introductionmentioning

confidence: 99%

“…For national status surveys in Scotland, line transects are conducted in winter (Ewing et al 2012). However, the species currently has a low population density and variable detectability relating to habitat type, sex and temperature (Ewing et al 2012). As a result, the 2009-10 national transect survey only recorded an average of one capercaillie encounter per 22.2 km of transect.…”

Section: Text Introductionmentioning

confidence: 99%

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A first test of unattended, acoustic recorders for monitoring CapercaillieTetrao urogalluslekking activity

Abrahams

Denny²

2018

Bird Study

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Estimating capercaillie Tetrao urogallus population size in Scotland from annual leks and counts of broods over the period 2010–2020

Baines

Aebischer

2023

Wildlife Biology

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The population size of capercaille Tetrao urogallus in Scotland was estimated from annual counts of males at 151 known spring lek sites and 45 counts of males, females and their broods in August during the period 2010–2020, combined with published survival estimates. Population size declined from an estimated 580 birds (95% CL: 462–698) in 2011 to 304 (239–369) in 2020 and the extinction probability was 23% after 25 years, 95% after 50 years and 100% after 100 years. Removing mortality associated with collisions against fences lowered extinction probabilities to 0, 3 and 40% respectively, emphasizing fence removal as a management priority. Greatest declines occurred in Deeside and Donside, Morayshire and Ross‐shire and Perthshire and Trossachs. In the Badenoch and Strathspey stronghold, where an estimated 83% of males remain, numbers of occupied leks and lekking males have decreased in the last five years and are associated with reduced breeding success over the last 10 years. Our estimates of population size are only half that derived from the last official national survey in winter 2015/2016. We discuss possible reasons for this difference including underestimates from lek‐based surveys linked to male detection probabilities. Finally, we recommend improvements to the current annual monitoring scheme, including repeat counts at leks and use of novel remote acoustic devices and restoration of annual brood counts in remaining key forests.

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The size of the Scottish population of CapercaillieTetrao urogallus: results of the fourth national survey

Cited by 13 publications

References 28 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.)

A first test of unattended, acoustic recorders for monitoring CapercaillieTetrao urogalluslekking activity

Estimating capercaillie Tetrao urogallus population size in Scotland from annual leks and counts of broods over the period 2010–2020

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