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Productivity (offspring production) is a key demographic parameter influencing population dynamics, particularly in r-strategy species, and thus critical for implementing well-based management of populations. Accordingly, the study of factors influencing productivity is useful to develop management strategies in species of conservation concern or subject to exploitation. We studied productivity (covey size and young/adult ratio) of red-legged partridges (Alectoris rufa) in Spain through a large-scale sampling in Andalucia and Castilla-La Mancha, two large areas in central-southern Spain, the core of the distribution of the species. We evaluated potential environmental factors related with productivity that have been considered important in previous local studies (weather, land use, and intensity of releases of farm-reared partridges), using a dataset of 15,357 observations of partridges over three breeding seasons (2010, 2011, and 2012). Average productivity at the end of July was 3 young/adult, indicating 50% chick mortality between hatching and fledging and high breeding failure. We found marked effects of weather, year, and land use on partridge productivity, confirming some previous results at local scale and supporting widespread and simultaneous effects of these factors. We also detected a large-scale negative relationship with farm-bred partridge release intensities, with lower young/adult ratios in areas with high release intensity. This suggests that partridge releases may be contributing to the decline of wild populations. Our results support that correcting the effects of agricultural intensification is the main key to the long-term conservation of the species and suggest that, in dry spring years (leading to low average productivity), many populations could be exposed to overhunting. These results stress the importance of both small- and large-scale adjustments of hunting pressure to partridge productivity, in order to preserve wild populations. Poor hunting bags in “bad” years, along with the increasing demand in the hunting market, may have stimulated the widespread use of releases, further reducing productivity and leading to the current compromised conservation status of wild populations. We discuss some potential solutions to this conflicting situation from the socioeconomic and environmental points of view., This work has been made possible by the Project: “Monitoring for the determination of egg-laying dates of red-legged partridge Alectoris rufa” funded by the Regional Governments of Castilla-La Mancha and Andalucia.

Complex body designs, such as plumage ornaments in birds, can be described by fractal geometry. These complex patterns could have a role as visual signals during courtship and social interactions, but an empirical validation in the wild is currently lacking. Here, we investigated whether the fractal dimension (FD) of a complex plumage pattern displayed by red-legged partridges Alectoris rufa could function as a potential sexual signal. We captured wild birds early in the breeding season and tested if mated and unmated birds differed in the FD of their conspicuous melanin-based black bib. We also tested if the FD of the black bib was correlated within the pair, looking for evidence of assortative mating based on the expression of this trait. We simultaneously assessed similar effects in other ornamental traits (black bib size, white throat patch and black flank band surface, redness of the eye rings and bill). Mated birds showed higher black bib FD values than unmated ones. Mated males, but not females, also displayed a larger black bib. Moreover, the black bib FD (but not the trait size) and the white throat patch surface showed assortative mating. Finally, females with higher black bib FD showed smaller black flank band surface, suggesting a trade-off in the expression of the two melanin-pigmented plumage traits. This provides unique and novel indication for the shape complexity of a pigmented trait, here described by its fractal dimension, to be potentially under sexual selection in a wild animal., A.C. was funded by a Juan de la Cierva-formación postdoctoral grant (FJCI-2015-23536; Ministerio de Economía, Industria y Competitividad, MINECO). Financial support was obtained from the projects PII1I09-0271-5037, PII1C09-0128-4724 and SBPLY/17/180501/000468 from the JCCM and CGL2009-10883-C02-02 from Ministerio de Ciencia e Innovación (Spain). F.C. was supported by the University of Maryland.

In Europe, hunting and game management are centuries-old activities that have had profound effects on the landscapes and the biodiversity they support. Game management is a potentially important tool to enhance game populations and may also affect other wildlife. We investigated the relationship between red-legged partridge Alectoris rufa game management and steppe-bird abundance in central Spain. We surveyed 54 red-legged partridge hunting estates with varying game-management intensity in spring and/or summer in 2006 and 2008–2010. Information about game management was gathered through questionnaires to game managers. Birds were counted from fixed points and the amount of different land uses in each point was visually estimated. Our results show that the abundance of granivorous species (sandgrouse) increased significantly with the density of feeders, whereas non-granivorous species were more abundant in estates with more intensive fox control, although the latter relationship was weaker. Land-use variables, specifically agricultural lands, appeared in the models of all the groups considered. Therefore, there is an option for designing optimal management for red-legged partridge estates that potentially benefits non-target species: an effective combination of habitat management, adequate use of supplementary food and water, and possibly selective legal predator control when necessary and effective for the target game species, although the latter needs further investigation.

In southern Europe, traditional hunting has been frequently replaced by models based on more intensive management. These systems include management strategies like the release of farm-reared animals that can cause harmful effects on biodiversity. However, little is known about the hunters’ views of this activity, and about their preferences for the ecological attributes of the hunting estates. We present the results of a choice experiment exercise evaluating the willingness to pay of Spanish hunters regarding different aspects of walked-up red-legged partridge (Alectoris rufa) shooting, including partridge quality (farm-reared vs. wild) and other attributes related to the ecological characteristics of the estate. We find that, when given the choice, hunting an additional wild partridge in a walked-up shooting day was valued more than 20 times higher than hunting an additional farm-reared bird. The diversity of small game available and the presence of natural vegetation in the landscape in which the walked-up hunting takes place were also significantly valued. Hunters also attributed economic value (albeit lower than other attributes) to the presence of protected non-game fauna in the estate. Overall, our results show that hunters are willing to pay more for hunting on estates that have better ecological characteristics, which may be indicative of good conservation status. This suggests that identifying and promoting such estates could lead to systems that are both ecologically and economically sustainable., This work was supported by the European Commission under the 7th FWP for Research and Technological Development, project HUNT (212160, FP7-ENV-2007-1). M. D-M. is currently supported by a JAE-DOC contract (Programa Junta para la Ampliación de Estudios), funded by CSIC and the European Social Fund (ESF). J.C. had a postdoctoral contract jointly funded by the ESF and by the Junta de Comunidades de Castilla–La Mancha (Spain), Operational Programme FSE 2007–2013.

In the last decades, the release of large numbers of farmed-reared birds became a widespread management practice for game species. The red-legged partridge (Alectoris rufa) is a quarry species with a high economic impact in rural areas of southwest Europe. In order to increase productivity and produce heavier birds, farmed red-legged partridges have often been hybridized with Chukar partridges (A. chukar), although these species have allopatric distribution ranges. During restocking, hybrid birds may be released into wild populations and may subsequently successfully breed, thus threatening the genetic integrity of native A. rufa populations. In this study, we compared several phenotypic indicators (body size, body condition and physiological state) between >pure> and hybrid partridges in order to evaluate the possible consequences of A. chukar genetic introgression into A. rufa. For this purpose, we captured 115 wild red-legged partridges during the breeding seasons 2003-2005 in four game estates of central Spain. We observed a greater occurrence of hybrid A. rufa × A. chukar partridges nearby the sites where the release of farmed-birds took place. We also found that hybrid males were smaller and hybrid females had better body condition and lower plasma carotenoid concentration than pure partridges of the same sex. Low carotenoid levels in blood plasma might be a limitation for female reproduction (fewer carotenoids available for ornamentation or to allocate to eggs). Overall, our results showed a greater occurrence of hybrids near restocking areas and phenotypic differences between hybrids and >pure> partridge in the wild. Genetic controls of farm-reared partridges should be a key step to prevent the releases of hybrids and ensure the maintenance of the genetic integrity of wild red-legged partridge populations., Fabián Casas was supported by a post-doctoral grant of the Junta de Comunidades de Castilla la Mancha (JCCM), and a JAE-Doc contract of the program «Junta para la Ampliación de Estudios» financed by the European Social Fund (ESF). This work alsoreceived a grant by the research project ‘‘Bases científicas preliminares para un plan de conservación de la perdiz roja en Castilla-La Mancha’’ of the Consejería de Agricultura y Medio Ambiente de la JCCM (Junta de Comunidades de Castilla-La Mancha), and CYCIT projects MCYT-REN200307851/GLO and CGL2004-02568/ BOS. FM was supported by a Grant from the Ministerio de Educación y Ciencia, Spain (CGL 2006-11823) and from the JCCM, Spain (PAI06-0112).

[ES]: Recopilamos el conocimiento científico actual sobre la ecología y gestión cinegética de la perdiz roja, haciendo hincapié en los hallazgos de los últimos años. La perdiz roja es una especie cinegética muy apreciada, cuyo estatus de conservación ha sido, y probablemente es, delicado. En los cotos de caza menor se dedican grandes esfuerzos a su gestión, pero muchas prácticas se aplican sin conocer las consecuencias que tienen para las poblaciones de perdiz. Los estudios revisados indican que el modelo de gestión más adecuado para aumentar la abundancia de esta especie, manteniendo la integridad biológica de sus poblaciones al tiempo que se cazan, incluye un ajuste apropiado de la presión cinegética a la abundancia anual de perdices, el manejo del hábitat promoviendo la vegetación natural en la matriz agrícola y la presencia de lindes, y el aporte suplementario de agua y comida. La información sobre la eficacia del control legal de depredadores generalistas para incrementar la abundancia de perdiz no es concluyente. Las sueltas de perdices de granja ponen en riesgo la integridad genética de la especie. Además, cuando se sueltan en pequeñas cantidades, no aumentan las bolsas de caza ni la rentabilidad económica de los cotos, pero afectan negativamente a la productividad de las poblaciones silvestres de perdices. A pesar del ocio y movimiento económico que genera la caza de perdiz roja, una gestión inadecuada reduce los beneficios potenciales de la actividad., [EN]: We review scientific knowledge on red-legged partridge ecology and management, focusing on recent studies. Red-legged partridge is a greatly valued game species, whose conservation status has been, and probably still is, poor. In small-game hunting estates, great efforts are devoted to red-legged partridge management, but many practices are applied without knowing their real consequences for partridge populations. Reviewed studies show that the most successful management options to increase the abundance of the species, allowing a sustainable harvest, would include an adequate adjustment of annual harvest to partridge abundance, appropriate habitat management promoting the presence of natural vegetation within the farmland matrix and field edges, and water and food supplementation. Information about the efficacy of predator control to increase red-legged partridge abundance is inconclusive. Releases of farm-reared partridges are putting at risk the genetic integrity of the species. Furthermore, when few partridges are released, releases do not increase annual harvest or estate profitability, and negatively affect the productivity of wild red-legged partridges. Despite leisure and economic movement generated by red-legged partridge hunting, inadequate management is currently reducing the potential benefits of this activity.

The red-legged partridge (Alectoris rufa) is the most important gamebird in Spain. Due to population declines in recent decades, management approaches increasingly include the release of farm-reared partridges and the establishment of so-called intensive estates, where hunting is based on put-and-take partridges. The release of farm-reared partridges is controversial because these birds negatively affect wild populations. However, according to managers, releases are necessary to maintain commercial hunting. We analysed economic parameters using data provided by 20 red-legged partridge hunting estates with different management and economic aims in central Spain. We calculated total revenues, total expenses, benefits and profitability of these estates and simulated results under two different scenarios (prices for buying farm-reared partridges being 15 % higher and prices for hunting in estates not using releases being 15 % higher) attempting to mimic the internalization of some ecological costs of farm-reared birds or possible rewards from using wild populations sustainably. Non-commercial estates (n = 5), as expected, just broke even, with almost no benefits. Benefits of intensive estates, where massive releases throughout the hunting season allow a much higher harvest, were on average an order of magnitude higher (20,404 ± 24,413 €/km, n = 8) than those of other commercial estates (1713 ± 1280 €/km, n = 7). Benefits of non-intensive commercial estates using releases were on average lower than those of commercial estates without releases. In fact, profitability of non-intensive commercial estates not using releases was similar to that of intensive estates. Any of the two price scenarios considered led to non-intensive commercial estates not using releases being the most profitable on average. Thus, efforts should be made to identify ways of improving economic profitability of non-intensive estates, which may be important for promoting hunting management styles that are ecologically more beneficial., Work was supported by the European Commission (7th Framework Programme for R&D through project HUNT, 212160, FP7-ENV-2007-1), JCCM through project ‘Efecto del medio natural, las prácticas agrícolas, ganaderas y de gestión cinegética sobre las poblaciones de caza menor en los cotos pertenecientes a la Asociación de cotos de caza Sierra de Alcaraz Campo de Montiel’, and by CSIC (PIE 201330E105). S. Díaz Fernández had a predoctoral grant funded by the European Social Fund (ESF) and by JCCM (Operational Programme PRINCET 2005-2010). M. Delibes-Mateos is supported by the V Plan Propio de Investigación of the University of Seville.

A basic rule to attain sustainable use of harvested resources is to adjust take to availability. Populations of red-legged partridges in Spain have decreased in recent decades, and releases of farm-bred partridges to improve short-term availability are increasingly common. We used questionnaires and bird surveys to assess whether harvest was related to availability of wild partridges or intensity of farm-bred partridge releases. We studied 50 hunting estates, including 6 administratively labeled as intensive (with few numerical and temporal restrictions to releases). In addition, we considered hunting pressure (number of hunters × hunting days/km2) and habitat as explanatory variables in the analyses. In intensive estates, annual harvest was exclusively related to release intensity, indicating that in these estates hunting is detached from natural resources and approaches an industrial activity based on external inputs. In non-intensive estates, harvest was affected by wild stock availability, walked-up shooting pressure, and habitat (greater harvest in estates with more Mediterranean shrubland). In these estates, releases did not increase annual harvest, and can be considered an inefficient practice. Additionally, the relationship between abundance estimates and harvest disappeared in estates with low partridge abundance estimates, suggesting possibilities for overharvesting in a large proportion of estates. Increasing the abundance of wild red-legged partridge through techniques like habitat management, and improving the adjustment of harvest to availability, may be a good strategy to increase long-term harvest in non-intensive estates. Additionally, Government and managers must create ways to segregate and label the estates where only wild red-legged partridges are managed from those where releases are used, to reduce ecological costs of management decisions., This work was supported by the European Commission under the 7th Framework Programme for Research and Technological Development through project HUNT (212160, FP7-ENV-2007-1) and the Consejería de Agricultura of Junta de Comunidades de Castilla-La Mancha (JCCM).

Hyperpredation can be described as a restrictive case of apparent competition where an increased number of primary prey species indirectly induces the decrease of the secondary prey species through numerical response of predators to the primary prey dynamics. It has been proposed that rabbit hemorrhagic disease (RHD), which decimated populations of European wild rabbit (Oryctolagus cuniculus) in Spain, led to prey switching by raptors towards red-legged partridges (Alectoris rufa) causing declines in their populations as a peculiar case of hyperpredation. We have reviewed field studies that disagree with estimates (based on bag records) of recent increases of rabbit and partridge numbers in Spain. Because of an increase in releases of farm-reared animals, there is doubt about the use of bag records to accurately estimate population trends in recent decades. We also provide new data and discuss some analytical considerations related to the temporal and spatial scales that might affect the interpretation of data. Finally, we discuss why studies associated with raptor food habits, predator population dynamics and predator distribution suggest that diet data are not sufficient to link patterns and processes. Although we agree that the RHD outbreak has markedly affected rabbit populations, which has indirectly affected many other species in the Iberian Peninsula, we consider that hyperpredation mediated by raptors has not been clearly demonstrated. In contrast, endorsing the hypothesis of raptor-mediated hyperpredation without sufficient proof may have conflictive consequences if we consider the increased persecution of raptors in recent decades in Spain., J.A. Blanco-Aguiar was supported by Fundação para a Ciência e a Tecnologia (SFRH/BPD/65464/2009) grant. M. Delibes-Mateos was supported by a Juan de la Cierva research contract awarded by the Ministerio de Ciencia e Innovación—Fondo European Social Fund. F. Casas was supported by a postdoctoral grant of the Junta de Comunidades de Castilla la Mancha (JCCM).

Oxidative stress is the imbalance between the production of pro‐oxidant substances and the level of antioxidant defenses, which leads to oxidative damage. It has been proposed that senescence is the result of accumulated oxidative damage throughout life. In birds, the sources of individual variability in oxidative stress are still poorly understood. Among these sources, age, as related to senescence, should be particularly relevant. Furthermore, recent findings suggest that breeding effort may also deeply influence susceptibility to oxidative stress. However, there is still no evidence of a link between breeding effort and oxidative damage in any vertebrate. Here we analyzed 288 captive red‐legged partridges (Alectoris rufa) across a wide age range (i.e., 1–8 yr old), thus including potentially senescent birds. In spite of limitations due to the cross‐sectional approach, results revealed that old birds produced less offspring and endured higher levels of oxidized glutathione and peroxidized lipids in erythrocytes than did middle‐aged individuals. Old birds also showed higher plasma total antioxidant status and uric acid levels than did younger birds, but lower amounts of circulating carotenoids. Furthermore, hatching success was negatively correlated to lipid peroxidation in females but not in males, supporting the hypothesis that breeding effort promotes oxidative damage., C.A.‐A. and L.P.‐R. were funded by a Ramon y Cajal Fellowship and a predoctoral Formación del Profesorado Universitario grant, respectively (Ministerio de Educación y Ciencia, Spain). The study was funded by Junta de Comunidades de Castilla–La Mancha (project PAI‐06‐0018) and Ministerio de Educación y Ciencia (project CGL2006‐10357‐C02‐02), both from Spain.

Double-nesting behaviour, a rare breeding system in which females lay in two nests, one incubated by herself and the other one by her mate, could be considered an intermediate stage in the evolutionary trend from biparental to uniparental care of single clutches. We examined the occurrence and success of double-nesting behaviour in Red-legged Partridges Alectoris rufa in Central Spain. Clutch size and hatching success were recorded, as well as the variation in these between years and between incubating sexes. Participation in incubation was higher for females (94.76%) than males (41.0%), and the proportion of incubating males varied markedly between years, with no incubating males in one dry year and approximately 50% of males incubating in other years. There was significant variation among years and between sexes in laying date, clutch size and hatching success. Clutch size decreased with later laying date in males and females. The probability of clutch loss to predation differed between sexes, being much higher for nests incubated by females. Our results suggest that both rainfall and predation influence the occurrence and success of double-nesting.

Wild red-legged partridge populations have experienced important declines in recent decades. With an aim to increase or maintain hunting quotas, releases of farm-reared red-legged partridges have concomitantly increased. However, the sustainability of this management practice is increasingly questioned. Farm-reared partridges suffer a high mortality rate immediately after release, and many released birds may already be dead before hunting takes place. Therefore, it is possible that if hunters adjust harvest to the number of farm-reared released birds, this may lead to an overhunting of the wild breeding stocks. We investigated here whether autumn mortality by hunting of radio-tracked birds that bred in the previous summer differed between hunting estates that use or do not use releases as part of their management practices. Although our sample size was limited (32 radio-tagged birds monitored throughout the hunting season in four estates, with only one conducting releases), our results report novel data that support this cause for concern. We found that hunting was the main cause of mortality and that the proportion of hunted partridges was much higher in the estate with releases of farm-reared birds than in the three estates that did not use releases. Therefore, the release of farm-reared partridges, instead of reducing hunting pressure on the breeding stock through a potential dilution effect, may have an opposite effect. This should be confirmed with more spatial replicates, but raises serious concerns regarding the long term sustainability of wild partridge populations and their exploitation for hunting purposes in estates that overhunt partridge populations due to releases., This study was supported by the Comunidad de Castilla-La Mancha (Bases científicas preliminares para un plan de conservación de la perdiz roja en Castilla-La Mancha) and Spanish Ministry of Science (MCYT-REN200307851/GLO and CGL2004-02568/BOS). FC was supported by the Andalucía Talent Hub Program launched by the Andalusian Knowledge Agency, cofounded by the European Union’s Seventh Framework Program, Marie Skłodowska-Curie actions (COFUND–Grant Agreement n° 291780) and the Ministry of Economy, Innovation, Science and Employment of the Junta de Andalucía.

We studied the helminth community and body condition of 99 hunter-harvested red-legged partridges (Alectoris rufa) from Ciudad Real (Central Spain). Forty-six were sampled in two game estates where an important number of farm-reared red-legged partridges are released yearly. The remaining 53 were obtained from natural wild populations adjacent to one of the estates with releases. Four nematode species (Heterakis gallinarum, Aonchoteca caudinflata, Eucoleus contortus and Cheilospirura gruveli) and two cestode species (Raillietina (R.) tetragona and Skryabinia bolivari) were identified. The managed areas showed higher parasite diversity, with higher prevalences and intensities for all helminths found. Three of these species were typical of farm-bred partridges and two of these, A. caundinflata and S. bolivari, were found parasitizing adult partridges. This suggests introduction of these helminths into the breeding population of managed states. The birds sampled in the nonmanaged estates showed a better body condition, but no relation with parasite infection was found. Our results suggest that the release of farm-reared red-legged partridges, a strategy that is becoming a common practice in Spanish hunting areas, poses risk to wild populations because of introducing parasites. However, these results also suggest that simply stopping releases may be a good way to remove locally those parasites from populations, as the establishment of the introduced parasites seems limited., This is a contribution to the joint project CSIC/Principado de Asturias and to CYCIT projects MCYT-REN200307851/GLO and CGL2004-02568/BOS. Lorenzo Pérez-Rodríguez had a FPU grant from the Spanish Ministerio de Educación y Ciencia and Fabián Casas from Junta de Comunidades de Castilla-La Mancha.

The release of farm-reared animals for shooting causes frequent conflicts between hunters and conservationists, since, while this management practice is economically important in some game areas, it carries several risks for biodiversity conservation (e.g. the introduction of new pathogens or the release of alien species and/or hybrids). However, these conflicts have received little attention in the literature. In particular, social-psychological factors, which are very important driving conservation conflicts, have been often ignored in the study of releases. Our main goal was to examine attitudes and beliefs of game managers towards the release of farm-reared red-legged partridges in small-game estates within central Spain, where more than 3 million partridges are released annually. Data were collected through face to face interviews with 45 game managers. More than 70% of the interviewed managers expressed negative views towards releases, and these included arguments about their detrimental effect on natural partridge populations, their low effectiveness, and their consideration as artificial hunting. Very negative views predominated among managers who had never released partridges (mostly those of non-commercial estates), and were frequently expressed by those who released partridges occasionally. In contrast, positive views were mostly given by managers who released partridges annually, and arguments used generally referred to the economic benefits of releases. Some managers expressed at the same time both positive and negative views on releases (i.e. ambivalent position). These findings suggest that there exists a relative polarisation among game managers, and that the position of those who were very critical of releases is close to that of conservationists. Our results also suggest that managers’ decision-making regarding releases is likely influenced by a variety of beliefs and attitudes as well as the socioeconomic setting (e.g. economic interest in the outcome of the behaviour). This highlights that the study of different aspects, including social and psychological as well as economic, is essential for understanding and resolving conservation conflicts, such as those caused by releases., This work was supported by the European Commission (7th Framework Programme for R&D through project HUNT, 212160, FP7-ENV-2007-1), by CSIC (PIE 201330E105), and by Junta de Comunidades de Castilla-La Mancha (PPII-2014-016-A). M. Delibes-Mateos is currently funded by Consejería de Economía, Innovación, Ciencia y Empleo of Junta de Andalucía, and the European Union's Seventh Framework Programme for research, technological development and demonstration under grant agreement 267226.

Knowledge about how hunting pressure is determined, and the relative efficacy of different mechanisms to regulate harvest, can help to improve the managers’ decision-making process. We developed a general framework about the decision-making process that regulates red-legged partridge (Alectoris rufa) hunting pressure in central Spain based on information from a focus group and individual interviews with game managers. We also used available information to compare the efficiency of different tools thus improving some decision steps. We evaluated the cost-effectiveness of different population monitoring methods as a way to reduce uncertainty on partridge availability to hunters. Additionally, we investigated the relationship between annual harvest and various regulatory mechanisms of partridge hunting pressure used in the study area to identify the most potentially useful one to limit annual take-off. Game managers usually set hunting pressure after a qualitative assessment on population abundance prior to the hunting season, but this decision was frequently modified during the course of the hunting season according to variations in catch or perceived abundance at that time. Our results showed that kilometric abundance indices (counting partridges from cars along line transects) was a simple cost-efficient and reliable estimate of partridge density (estimated by Distance sampling). A variety of regulatory mechanisms were used by managers. The variables that most affected annual harvest (in addition to partridge abundance) were the number of driven-shooting days, and hunter density in walked-up hunting days, suggesting that their adjustment will be the most efficient regulatory mechanisms. We conclude that adequate monitoring on population abundance should be a critical step for managers’ decision-making, and that a better understanding of the relative value of regulatory mechanisms, combining social and ecological approaches, would help improving our understanding of any human-mediated system, thus leading to better management recommendations., Work was supported by the European Commission (7th Framework Programme for R&D through project HUNT, 212160, FP7-ENV-2007-1); Consejería de Agricultura of JCCM; by the Ministerio de Ciencia y Tecnología (CGL2008-04282/BOS), and by CSIC (PIE 201330E105).

The reduction of game and fish populations has increased investment in management practices. Hunting and fishing managers use several tools to maximize harvest. Managers need to know the impact their management has on wild populations. This issue is especially important to improve management efficacy and biodiversity conservation. We used questionnaires and field bird surveys in 48 hunting estates to assess whether red-legged partridge Alectoris rufa young/ adult ratio and summer abundance were related to the intensity of management (provision of supplementary food and water, predator control and releases of farm-bred partridges), harvest intensity or habitat in Central Spain. We hypothesized that partridge abundance would be higher where management practices were applied more intensively. Variation in young/ adult ratio among estates was best explained by habitat, year and some management practices. Density of feeders and water points had a positive relationship with this ratio, while the density of partridges released and magpies controlled were negatively related to it. The variables with greatest relative importance were feeders, releases and year. Variations in postbreeding red-legged partridge abundance among estates were best explained by habitat, year, the same management variables that influenced young/adult ratio, and harvest intensity. Harvest intensity was negatively related to partridge abundance. The other management variables had the same type of relationship with abundance as with young/adult ratio, except magpie control. Variables with greatest relative importance were habitat, feeders, water points, releases and harvest intensity. Our study suggests that management had an overall important effect on post-breeding partridge abundance. However, this effect varied among tools, as some had the desired effect (increase in partridge abundance), whereas others did not or even had a negative relationship (such as release of farm-reared birds) and can be thus considered inefficient or even detrimental. We advise reconsidering their use from both ecological and economical points of view., This work was supported by the European Commission under the 7th Framework Programme for RTD through project HUNT (212160, FP7-ENV-2007- 1), the Consejería de Agricultura of JCCM through project ‘‘Efecto del medio natural, las prácticas agrícolas, ganaderas y de gestión cinegética sobre las poblaciones de caza menor en los cotos pertenecientes a la Asociación de cotos de caza Sierra de Alcaraz-Campo de Montiel’’, and the Ministerio de Ciencia y Tecnología (CGL2008-04282/BOS). S. Díaz-Fernández had a predoctoral grant funded by the European Social Fund (ESF) and by JCCM (Operational Programme PRINCET 2005-2010). F. Casas was supported by a JAE-Doc contract funded by the ESF. Currently, M. Martinez-Haro is supported by a postdoctoral grant (Ref: SFRH/BPD/73890/2010) funded by the Portuguese Foundation for Science and Technology (FCT), the ESF and POPH programme.

[Context]: In Spain, the release of farm-reared partridges to hunt is increasingly used, despite being thought to affect sustainability of wild stocks and to reduce the need of natural habitats for game. [Aims]: To explore the market value as a possible incentive for current management, we evaluated within a segment of the red-legged partridge hunting market whether the use of farm-reared birds (as opposed to wild stock) or the naturalisation of landscapes are affecting the hunt market price. [Methods]: We considered estates that sell individual hunting days and contacted buyers through advertisements. We gathered all advertisements for the 2010 season in four top hunting magazines and two websites, and conducted a telephone survey to record price and associated characteristics of hunts. We looked for relationships between price and the characteristics of sold hunts, using general linear models. [Key results]: Hunts varied largely in price, but neither restocking nor naturalisation of the landscape explained price variation, at least within our sample of estates. The absence of price difference between wild or released partridges could be reflecting the current difficulty to distinguish both kinds of products in the market. [Conclusions]: Market forces alone might not be promoting the public interest of the sustainable use of wild stocks versus industrial hunting based on farm-reared birds. [Implications]: If promoting conservation and sustainable use of wild stocks is considered a major goal of official institutions in charge of biodiversity conservation and game management, they should promote reliable ways of identifying estates selling wild or restocked partridges, and they should also evaluate benefits and costs associated with hunting farm-reared birds relative to wild birds, so as to help internalise these costs and benefits if necessary. A study of the determinants of hunter demands would also help explain variation in supply and market prices., This work was supported by the European Commission under the 7th Framework Programme for Research and Technological Development through project HUNT (212160, FP7-ENV-2007-1).

Many animal species show ornaments with yellow-orange-red colors produced by carotenoid pigments. Such traits have evolved as reliable signals of individual quality because of the costs inherent to their production or maintenance. In animal tissues, carotenoids are often found combined with free fatty acids, as carotenoid esters, which may confer more stability to coloration than free carotenoids. Surprisingly, the potential relevance of carotenoid esterification in the expression of animal sexual signals has been virtually ignored. Moreover, the sources of variability of esterified carotenoid levels are barely known, because most studies have not quantified their concentrations. Here, carotenoids in the ornaments (bill, eye rings, and legs) of red-legged partridges Alectoris rufa were quantified in their free and esterified forms. Carotenoid ester levels were the best predictors of leg color, whereas the redness of the other traits was better explained by free carotenoids. Nonetheless, total carotenoid levels (the sum of free and esterified forms) were always significantly correlated to redness. Young partridges had lower levels of free and esterified carotenids in the legs than did older individuals. Also, wild animals had higher ester levels and a higher proportion of carotenoids in esterified forms in all traits than did captive partridges. Probable physiological mechanisms explaining these patterns are discussed., Esther García-de Blas was supported by a predoctoral grant (JAE-PRE program) from the Consejo Superior de Investigaciones Científicas cofinanced by Fondo Socia Europeo. Lorenzo Pérez-Rodríguez was supported by a “Juan de la Cierva” postdoctoral contract from the Spanish Ministerio de Ciencia e Innovación (JCI-2008-2059). This study was funded by Consejería de Educación y Ciencia, Junta de Comunidades de Castilla la Mancha (PII1I09-0271-5037), and Ministerio de Economía y Competitividad (CGL2009-10883-C02-02) from the Spanish government.

22 páginas, 3 tablas, 2 figuras., Game management is widely implemented in Spain, affecting more than 70 % of land cover. Management intensity may be linked to the financial aims of hunting estates, but no study of these aspects has been developed in Spain, where commercial hunting is common. Through interviews with game managers and field surveys, we quantified physical and economic traits, management techniques and hunting methods in a sample of 59 small game hunting estates located in south-central Spain (where Red-legged partridge hunting has the highest socio-economic importance in the country). We compared non-commercial estates (aimed for leisure, managed mainly by local hunting societies) and commercial estates (aimed at financial benefit); among the latter, we also assessed “intensive” estates (a special category of commercial estates licensed to release farm-reared partridges without temporal or numerical limits throughout the hunting season). Commercial estates had more intensive management, including more and larger partridge releases, higher density of supplementary feeders and more intensive predator control. Thus, any positive or negative effects on biodiversity of these management techniques would be higher in commercial than in non-commercial estates. Commercial estates also retained more natural vegetation, which may help to enhance the landscape and biodiversity value of farmland in central Spain. On the other hand, differences in management and hunting styles were most marked between intensive and other type of estates (both commercial and non-commercial); this indicates that intensive estates are qualitatively different from other small game estates, both ecologically (hunting based on releases and driven shooting) and economically (higher inputs and outputs). It would be desirable to find ways to quantify the environmental or social costs and benefits of different management techniques, and integrate them in the economics of hunting estates., This work was supported by the European Commission under the 7th Framework Programme for Research and Technological Development through project HUNT (212160, FP7-ENV-2007-1), Ministerio de Ciencia y Tecnología (CGL2008-04282/BOS) and the Consejería de Agricultura of Junta de Comunidades de Castilla-La Mancha (JCCM). Additionally, this paper uses partial data from a project funded by the Fundación Fauna y Flora. S. Diaz-Fernandez had a predoctoral grant jointly financed by the European Social Fund and by JCCM, in the framework of the Operational Programme PRINCET 2005-2010. M. Delibes-Mateos is currently holding a Juan de la Cierva research contract awarded by the Ministerio de Ciencia e Innovación and the European Social Fund. We thank all game managers for their collaboration, and ADEMAC and the Asociación de cotos de caza menor Sierra de Alcaraz-Campo de Montiel for facilitating this collaboration with game managers. We thank Steve Redpath, Mick Marquiss, Justin Irvine and two anonymous referees for useful comments on the manuscript.

Hybridization is a widespread phenomenon, which plays crucial roles in the speciation of living beings. However, unnatural mixing of historically isolated taxa due to human-related activities has increased in recent decades, favouring levels of hybridization and introgression that can have important implications for conservation. The wild red-legged partridge (Alectoris rufa, Phasianidae) populations have recently declined and the releases of farm-reared partridges have become a widespread management strategy. The native range of the red-legged is limited to the south-west of Europe (from Italy to Portugal). This species does not breed in sympatry with the chukar partridge (A. chukar), whose range is Eurasian (from Turkey to China). However, red-legged partridges have often been hybridized with chukar partridges to increase the productivity of farmed birds, and game releases may have spread hybrid birds into the wild. In this study, we investigated the fitness (survival and breeding) differences between hybrid and >pure> red-legged partridges in a wild population located in central Spain. Incubation probability was similar in hybrids and >pure> partridges. Hybrid females laid larger clutches than >pure> ones, but hatching success did not differ between hybrid and >pure> partridges. Hybrid birds had lower survival rate than >pure> ones, mainly because of higher predation rates. Our results show that, despite lower survival, hybrid partridges breed in natural populations, so this could increase extinction risk of wild pure partridge populations, through releases of farmed hybrid birds. The consequences of continued releases could be of vital importance for the long term conservation of wild red-legged partridges., F. Casas was supported by a pre-doctoral grant of the Junta de Comunidades de Castilla la Mancha (JCCM). This work also received financial support from the research projects ‘‘Bases científicas preliminares para un plan de conservacion de la perdiz roja en Castilla-La Mancha’’, and ‘‘Caracterización y diagnóstico genético de las poblaciones de perdices de Castilla-La Mancha’’ of the Consejería de Agricultura y Medio Ambiente de la JCCM (Junta de Comunidades de Castilla-La Mancha), and CYCIT projects MCYT-REN200307851/GLO and CGL2004-02568/BOS. IS-B was supported by a FEDENCA-Royal Spanish Federation of Hunting contract. FM was supported by Grants from the Ministerio de Educación y Ciencia, Spain (CGL 2006-11823) and from the JCCM, Spain (PAI06-0112 and PAII1C09-0227-0104).

Yellow-orange-red ornaments present in the integuments (feathers, bare parts) of birds are often produced by carotenoid pigments and may serve to signal the quality of the bearer. Although carotenoid esterification in tissues is a common phenomenon, most of the work on avian carotenoids has been focused on the identification of free forms or have been done after sample saponification. Here we determined free and esterified carotenoid composition in a bird species with red ornaments: the red-legged partridge (Alectoris rufa). Carotenoids from leg integument were extracted and processed by TLC to separate three major carotenoid groups (free form, mono- and diesters with fatty acids), whereas saponified extracts gave only free forms of carotenoids. TLC fractions were then analyzed by HPLC-DAD with C18 phase column for a preliminary identification of carotenoid groups. The final characterization of free carotenoids and its esters with fatty acids was performed with direct extracts analyzed by LC-MS and LC-MS/MS with a C30 phase, always with a system coupled to DAD. The main carotenoid (λmax 478nm and [M+H]+ at m/z 597.2) was identified as astaxanthin by comparison with standards. A second carotenoid (λmax between 440 and 480nm and [M+H]+ at m/z 581.3) was not identified among any of the commercially available carotenoid standards, although it could correspond to pectenolone according to its fragmentation pattern. Both the unidentified carotenoid and astaxanthin formed monoesters with fatty acids, but only astaxanthin was in its diesterified form. Monoesters were mainly formed with palmitic, stearic, oleic and linoleic acids. Complementary analyses of fatty acid composition in partridge integument by GC-MS revealed high amounts of these and other fatty acids, such as myristic, arachidic and docosanoic acids. The combination of HPLC-DAD and LC-MS/MS spectra was especially useful to identify the carotenoids present in the esterified forms and the probable masses of the fatty acids included in them, respectively., Esther García de Blas was supported by a predoctoral grant (JAE-PRE) from the Consejo Superior de Investigaciones Científicas (CSIC). This study was funded by Consejería de Educación y Ciencia, Junta de Comunidades de Castilla la Mancha (Spanish Government; project: PII1I09-0271-5037).

European agricultural landscapes hold important endangered and game species, which may add socioeconomical and ecological value to the ecosystem, and thus must be considered priority species in any management programme integrating agriculture, hunting and conservation. Patterns of red-legged partridges (Alectoris rufa) nesting habitat selection and nesting success provide information for the implementation of these kinds of programmes in agrarian pseudosteppes. Nests occur mainly in cereal grain fields, although this habitat type was overall negatively selected and had the lowest nesting success. Only lindes (herbaceous strips among fields) were positively selected, and were also the habitat type with the highest nesting success. Nests within cereal grain fields were positively selected close to the field margins (mostly < 5 m). Agricultural practices, particularly harvesting, were the main cause of nest failure. Changes in agricultural practices would be a more effective means of increasing nesting success than predator control. Partridge breeding success may be improved by better management of agricultural areas, increasing the availability of lindes and slightly delaying cereal harvesting. These data may have implications for other endangered steppe-birds with similar nesting habitat, and may provide the basis for effective and successful collaborative programmes between hunters and conservationists., Fabian Casas received support from a pre-doctoral grant of the Junta de Comunidades de Castilla-La Mancha (JCCM) and financial support from the CYCIT projects MCYT-REN200307851/GLO and CGL2004-02568/BOS.

We present the first description of interspecific nest parasitism in Common Quail. Incidence was low; only two nests contained common quail eggs out of 82 Red‐legged Partridges nests., During this study F. Casas received support from a pre-doctoral grant of the Junta de Comunidades de Castilla La Mancha (JCCM). This work also received financial support from the research projects ‘Bases científicas preliminares para un plan de conservación de la perdiz roja en Castilla-La Mancha’ of the Consejería de Agricultura y Medio Ambiente de la JCCM (Junta de Comunidades de Castilla-La Mancha), and CYCIT projects MCYT-REN200307851/GLO and CGL2004-02568/BOS. Francois Mougeot was supported by a NERC advanced fellowship, a Grant from the Ministerio de Educación y Ciencia, Spain (CGL 2006-11823) and from the JCCM, Spain (PAI06-0112).

Blood biochemical parameters may provide useful information about the physical condition of the individual, making them a useful tool in ecological studies. However, to avoid biases, factors affecting circulating levels of plasma metabolites must be investigated. In this paper, we analyse the effect of daytime sampling hour on seven plasma metabolites in adult red-legged partridges (Alectoris rufa) with free access to food during the breeding season. We found that sampling hour affected circulating levels of glucose and triglycerides but not those of cholesterol, total protein, uric acid, urea or albumin. A sex effect was found only for glucose, uric acid, urea and triglycerides. Repeated sampling affected all the parameters studied. These results suggest that the effect of sex, sampling hour and repeated sampling should be carefully controlled for (methodologically or by statistical procedures) to avoid undesirable sources of error at least in some blood parameters., Financial support was provided by the Research Project PAI-02-006 of the Junta de Comunidades de Castilla-La Mancha. L.P.R. was supported by an FPU grant of the Spanish Ministerio de Educacion y Ciencia. C.A.-A. was supported by a Ramon y Cajal fellowship (Ministerio de Educacion y Ciencia, Spain). M.M.-H. was supported by a postgraduate grant (I3P) from CSIC and the Research Proyect CGL2004-02568/BOS of the Spanish Ministerio de Educacion y Ciencia.

Game bird farming is associated with high parasite levels that reduce farm productivity, reduce survival after releasing, and may pose a health risk for natural populations. The efficacy of albendazole (orally, 20 mg kg(-1) was evaluated in farmed red-legged partridges naturally infected with the nematodes Aonchotheca caudinflata and Heterakis gallinarum. In treated birds body condition improved, nematode egg deposition was reduced and the proportion of gravid A. caudinflata females was reduced, but not the overall worm burdens. Albendazole was found to be 36.8% and 17.1% effective against A. caudinflata and H. gallinarum, respectively. These results indicate that the anthelmintic treatment used normally in Spanish partridge farms is not effective enough to avoid the introduction of parasites into the field after release., This research contributes to the agreement IREC - Principado de Asturias. L. Pérez-Rodríguez has a FPU grant and O. Rodríguez a Torres Quevedo contract partly supported by MEC.