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The aim of this paper is to determine how people value species for conservation and apply it to policymaking. This paper is the first attempt to value one of the UK´s rarest birds specifically; the redbilled chough (Pyrrhocorax pyrrhocorax). Classical economic theory struggles to assign value to resources that are not a product of markets, such as endangered wildlife. The contingent valuation method will be used to gauge how P pyrrhocorax is valued in Cornwall via a questionnaire method, eliciting responses to how much individuals are willing to pay to preserve this rare species. The methodology requires diligent questionnaire design, implementation and regression analysis. It was found that the average willingness to pay was £23.60 to mitigate habitat damage to this endangered and iconic bird. Economic valuation has a large role to play in determining policy for species conservation. However, there are other more complex and non-orthodox forms of valuation occurring such as aesthetic, intrinsic bequest and relational values that cannot be accounted for by direct valuation. [ABSTRACT FROM AUTHOR]

Heavy snowfall during the winter 2017-2018 together with expansion of Red-billed Chough beyond its breeding area no doubt favorised the wintering of two individuals at Bex (canton of Vaud) at 440-530 m. They were observed between 15 December and 19 March and also seen regularly the following winter (5 January-21 March) in pastures with scattered cow pads. In view of the fact that on some occasions they were not present and from other observations it is likely that other sites were visited within the neighbourhood. [ABSTRACT FROM AUTHOR]

1. A population's effective size (Ne) is a key parameter that shapes rates of inbreeding and loss of genetic diversity, thereby influencing evolutionary processes and population viability. However, estimating Ne and identifying key demographic mechanisms that underlie the Ne to census population size (N) ratio, remains challenging, especially for small populations with overlapping generations and substantial environmental and demographic stochasticity and hence dynamic age-structure. 2. A sophisticated demographic method of estimating Ne/N, which uses Fisher's reproductive value to account for dynamic age-structure, has been formulated. However, this method requires detailed individual and population-level data on sex and age-specific reproduction and survival and has rarely been implemented. 3. Here, we use the reproductive value method and detailed demographic data to estimate Ne/N for a small and apparently isolated red-billed chough (Pyrrhocorax pyrrhocorax) population of high conservation concern. We additionally calculated two single-sample molecular genetic estimates of Ne to corroborate the demographic estimate and examine evidence for unobserved immigration and gene flow. 4. The demographic estimate of Ne/N was 0.21, reflecting a high total demographic variance (σ 2 dg) of 0.71. Females and males made similar overall contributions to σ 2 dg. However, contributions varied among sex-age classes, with greater contributions from 3 year-old females than males, but greater contributions from ⩾5 year-old males than females. 5. The demographic estimate of Ne was ∼30, suggesting that rates of increase of inbreeding and loss of genetic variation per generation will be relatively high. Molecular genetic estimates of Ne computed from linkage disequilibrium and approximate Bayesian computation were approximately 50 and 30, respectively, providing no evidence of substantial unobserved immigration which could bias demographic estimates of Ne. 6. Our analyses identify key sex-age classes contributing to demographic variance and thus decreasing Ne/N in a small age-structured population inhabiting a variable environment. They thereby demonstrate how assessments of Ne can incorporate stochastic sex and age-specific demography and elucidate key demographic processes affecting a population's evolutionary trajectory and viability. Furthermore, our analyses show that Ne for the focal chough population is critically small, implying that management to re-establish genetic connectivity may be required to ensure population viability. [ABSTRACT FROM AUTHOR]

1. Understanding the degree to which reproductive success varies with an individual’s age and lifespan, and the degree to which population-level variation mirrors individual-level variation, is central to understanding life-history evolution and the dynamics of age-structured populations. We quantified variation in the survival probability of offspring, one key component of reproductive success and fitness, in relation to parent age and lifespan in a wild population of red-billed choughs ( Pyrrhocorax pyrrhocorax). 2. On average across the study population, the first-year survival probability of offspring decreased with increasing parent age and lifespan; offspring of old parents were less likely to survive than offspring of young parents, and offspring of long-lived parents were less likely to survive than offspring of short-lived parents. 3. However, survival did not vary with parent age across offspring produced by groups of parents that ultimately had similar lifespans. 4. Rather, across offspring produced by young parents, offspring survival decreased with increasing parent lifespan; parents that ultimately had long lifespans produced offspring that survived poorly, even when these parents were breeding at young ages. 5. The average decrease in offspring survival with increasing parent age observed across the population therefore reflected the gradual disappearance of short-lived parents that produced offspring that survived well, not age-specific variation in offspring survival within individual parents. 6. The negative correlation between offspring survival and maternal lifespan was strongest when environmental conditions meant that offspring survival was low across the population. 7. These data suggest an environment-dependent trade-off between parent and offspring survival, show consistent individual variation in the resolution of this trade-off that is set early in a parent’s life, and demonstrate that such structured life-history variation can generate spurious evidence of senescence in key fitness components when measured across a population. [ABSTRACT FROM AUTHOR]

We studied the effect of capture and handling on free-living red-billed choughs Pyrrhocorax pyrrhocorax. We analysed the association between bird behavioural response and individual health, breeding status, sex, and age. Active responses (aggression towards the ringer, screaming) were more common in the breeding period, and in individuals with a high heterophils to lymphocytes ratio, indicating poor physiological condition and/or high chronic stress. Adults were more aggressive than juveniles and yearlings, and females were more aggressive than males. Sex, age, and condition differences were also recorded in the spectrotemporal output of distress calls. Birds with a screaming/active response appeared to be more stress-susceptible than passive and silent individuals, and this response was stronger during the energy demanding period of reproduction. The results obtained suggest that the response of the red-billed chough during capture might primarily reflect stress-susceptibility, although a number of potential alternative explanations are discussed. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 96, 846–855. [ABSTRACT FROM AUTHOR]

1. Understanding the pattern and magnitude of spatial variation in demography and population growth rate (λ) is key to understanding the structure and dynamics of natural populations. However, such spatial variation is challenging to quantify. We use > 20 years of individual life-history data to quantify small- and large-scale spatial variation in demography and λ within a single population of red-billed choughs Pyrrhocorax pyrrhocorax on Islay, Scotland. Critically, we demonstrate a major importance of an individual's natal rather than current location in driving observed spatial variation. 2. Breeding success (the number of offspring fledged per breeding attempt) varied among individual chough nest sites but did not vary on a larger spatial scale across Islay. 3. The proportion of fledglings observed to survive to recruiting age varied markedly among individual nest sites and also varied more widely across Islay. Spatial capture–mark–recapture models defined two discrete geographical regions where fledgling survival differed significantly: choughs fledged in region ‘BGE’ were more likely to survive than choughs fledged in region ‘CNSW’ as both subadults and adults. 4. The asymptotic λ attributable to breeding attempts in region BGE exceeded unity, and exceeded that attributable to breeding attempts in region CNSW. Relatively productive and unproductive regions therefore exist within this population. 5. Spatial variation in adult survival was better explained by an individual's natal region than the region where that individual settled to breed. Spatial variation in λ would consequently have remained undetected had survival been measured across resident breeders rather than across individuals fledged in each region. Furthermore, breeding success was a weak predictor of a nest site's estimated productivity of recruits. 6. We therefore describe marked spatial variation in demography and λ within a single population of a territorial vertebrate, mediated partly by long-term links between an individual's natal location and its subsequent life-history. Life-long monitoring of individuals of known origin may therefore be necessary to identify accurately subpopulations of intrinsically high and low λ. [ABSTRACT FROM AUTHOR]

Summary 1. Using data from a 20-year study of individually marked red-billed choughs, we examine how reproductive performance varies with age in male and female breeders, and investigate whether population-level trends result from changes in individual performance and/or the phenotypic composition of the breeding population. 2. Across the population, mean clutch size, the probability of breeding successfully and the number of offspring fledged during successful attempts increased and then declined with female age. Male age did not explain a significant proportion of the residual variation. 3. All three measures of reproductive performance improved and then declined with age within individual females. 4. Females that died young laid relatively small clutches and fledged few offspring before death. Thus mean performance improved across young age classes partly because some poor breeders were absent from older age classes. 5. Females that ultimately reached the greatest ages had laid small clutches and fledged few offspring during their first few breeding attempts. Females that were more productive when they were young had relatively shorter lives. These data indicate a trade-off between early reproduction and future survival in choughs, and suggest that individuals that reach old age are phenotypically distinct from an early stage in their breeding lives. 6. We emphasize that age-specific changes in mean reproductive performance observed across wild populations are due to a complex interplay between improvement and senescence at the individual level, as well as changes in the phenotypic composition of the breeding population. [ABSTRACT FROM AUTHOR]