Adult Survival Probability in a Recovered Population of Scops Owls<i>Otus scops</i>

Boano, Giovanni; Silvano, Fabrizio

doi:10.5253/arde.v103i2.a3

Cited by 4 publications

(6 citation statements)

References 39 publications

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“…1999). Our apparent adult survival estimate was similar (albeit slightly higher) than the one reported by Boano and Silvano (2015) using mist‐nets and capture–recapture models. We cannot exclude that our population size estimation was biased, but it is extremely unlikely that such a bias would explain the entire discrepancy.…”

Section: Discussionsupporting

confidence: 86%

“…The retrospective analysis suggests that this increase was mainly due to high survival of juveniles and first‐year birds and high fecundity parameters (particularly clutch size and fledging success), and to a lower extent due to high adult survival. Our mean apparent survival estimate (excluding juveniles) was 0.611 ± 0.083, very similar to the apparent survival of adult Scops Owls in northwest Italy (0.58 ± 0.07, Boano & Silvano 2015) and to other small owl species (Newton et al . 2016) but higher than the one reported for Scops Owls in southeast Spain (0.40 ± 0.04, Parejo et al .…”

Section: Discussionsupporting

confidence: 84%

“…However, to our knowledge this is currently the only way to study fecundity parameters and age-related survival rates for this species, as natural nests are extremely difficult to detect and to access in order to mark birds and measure fecundity parameters. Boano and Silvano (2015) and Parejo et al (2018) used mist-netting to study Scops Owls but could only estimate adult survival. Reassuringly, Vidal et al (1984) found similar clutch sizes and numbers of fledged chicks for Scops Owls breeding in natural cavities or in nestboxes in southern France, suggesting little bias cause by fecundity parameters due to nestboxes.…”

Section: Demography and Population Dynamics Of Scops Owls In A Landsc...mentioning

confidence: 99%

“…However, estimates of population sizes and trends for Scops Owls are scarce and imprecise (Bavoux et al 1997, Barnagaud & Caupenne 2015, Herrando et al 2020. Demographic data are even rarer (Bavoux et al 2011, Boano & Silvano 2015 because there are very few long-term field studies, partly due to the elusive behaviour (apart from vocal activities), breeding habits with low to medium attractiveness to nestboxes, and excellent camouflage of the species. As a consequence, we have a very poor understanding of the demographic tactics of this species, and nothing is known about the effects of climate on demographic traits and population dynamics.…”

Section: Introductionmentioning

confidence: 99%

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The demography of an increasing insular Eurasian Scops Owl (Otus scops) population in western France

Barbraud

Bavoux²,

Burneleau³

2021

Ibis

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Rapid population declines of many long-distance Afro-Palaearctic migratory bird species are ongoing across Europe but the demographic drivers are often poorly understood, thereby limiting the development of appropriate conservation actions. Using long-term population monitoring (39 years), capture-mark-recapture data and a matrix model, we estimated demographic parameters and the effect of climate variables on adult survival, and modelled the dynamics of an increasing population of Eurasian Scops Owls Otus scops in a landscape with agricultural abandonment in western France. The observed mean annual population growth rate was 1.055 (from 68 to 523 territorial males between 1981 and 2019). Over the study period, clutch size and hatching success were stable, but fledging success and breeding success showed slight negative trends, probably due to density-dependence. Survival varied with age, with an increase during early life and evidence for rapid senescence from 4 years old. Adult survival remained stable and was positively linked to the amount of autumn rainfall in the Sahel and to the winter North Atlantic Oscillation. Survival of younger age-classes made the largest contribution to the variance of the population growth rate, followed by clutch size, fledging success and survival of older birds. Such a long-term population increase in a landscape where intensive agriculture has decreased by 64.6% sheds some new light on the causes of the decline of European Scops Owl and other Afro-Palaearctic bird populations. We infer some of the possible causes of this large-scale decline, in particular food shortage, and discuss conservation measures that could be applicable to reverse this trend.

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Section: Discussionsupporting

confidence: 86%

Section: Discussionsupporting

confidence: 84%

Section: Demography and Population Dynamics Of Scops Owls In A Landsc...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The demography of an increasing insular Eurasian Scops Owl (Otus scops) population in western France

Barbraud

Bavoux²,

Burneleau³

2021

Ibis

View full text Add to dashboard Cite

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“…The species has shown widespread declines throughout a large part of its Western European breeding range, especially in Switzerland (Arlettaz 1990, Arlettaz et al 1991, Spain (Martinez et al 2007) and Northern Italy (Galeotti & Sacchi 2001, Treggiari et al 2013, mainly due to intensification of farming practices and land-use changes (Sergio et al 2009), so it was considered species of European Conservation Concern (BirdLife International 2004); but in the last years signs of local recovery (e.g. Caula & Beraudo 2014, Boano & Silvano 2015, Knaus et al 2018) and even of spreading towards North (Mebs & Nicklaus 2014) have been detected.…”

mentioning

confidence: 99%

Sex identification of Eurasian Scops Owl Otus scops using morphometric analysis

Boano

Tizzani

Rasero

et al. 2019

Ringing & Migration

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The Eurasian Scops Owl Otus scops is a migratory owl whose population is declining throughout a large part of its breeding range, due to intensification of farming practices and land-use changes. For this reason, it is considered the most threatened owl in Europe. Several raptor species like Scops Owl present limited possibility to differentiate between sexes, due to the reduced biometric and morphometric differences. The availability of a reliable method to sex Scops Owl through biometric measurements would facilitate the study of sex-related survival, movements and behavior characteristics of this species, improving conservation management projects. In the current study, we developed a cost-effective and accurate method of sexing Scops Owl, based on discriminant analysis of morphometry. One hundred and five birds were captured, sexed using genetic methods and biometric measures were taken. A GLM model was built to evaluate the biometric measures statistically linked to the sex. The best model (AIC = 49.211) selected three biometric measures: wing length, tail length, weight. The results of the model were used to derive models scores, and the predictive probability of male and female to be correctly identified was estimated. The discriminant function provides an accurate method of sexing Scops Owl in the hand.

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Factors affecting survival in Mediterranean populations of the Eurasian eagle owl

et al. 2016

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18The survival rate is a key parameter for population management and the monitoring of 19 populations. Thus, an analysis of survival rate variations and the factors influencing the 20 same is essential for understanding population dynamics. Here, we study the factors 21 determining the survival and the causes of mortality of the Eurasian eagle owl (Bubo 22 bubo) in two Spanish Mediterranean populations (Murcia and Seville) where the species 23 has a high population density and breeding success; yet its survival rates and the factors 24 that affect them are unknown. Between 2003 and 2010, 63 breeding owls were captured 25 and radio-tracked. Three-monthly (quarterly) survival rates were estimated using 26 known-fate models in the program MARK. The mean overall annual survival rate was 27 0.776 (95% CI = 0.773-0.779). We observed survival differences between sexes, and 28 between the breeding and non-breeding periods, although no overwhelming support was 29 found for any particular model. We concluded that: (i) females have a lower survival 30 rate than males, probably due to their larger home ranges, which increase the risk of 31 mortality; (ii) the survival rates of both sexes were lower during the non-breeding 32 period; and (iii) the causes of mortality differed significantly between the two 33 populations, gunshot being the main cause in Seville and electrocution in Murcia. 34 35 Keywords 36Home range · Human-induced mortality · Known-fate model · Sex-biased mortality. 37 3 Introduction 38

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Adult Survival Probability in a Recovered Population of Scops OwlsOtus scops

Cited by 4 publications

References 39 publications

The demography of an increasing insular Eurasian Scops Owl (Otus scops) population in western France

The demography of an increasing insular Eurasian Scops Owl (Otus scops) population in western France

Sex identification of Eurasian Scops Owl Otus scops using morphometric analysis

Factors affecting survival in Mediterranean populations of the Eurasian eagle owl

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