Reconciling economic and ecological sustainability: can non-intensive hunting of red-legged partridges be economically profitable?

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 €/km², n = 8) than those of other commercial estates (1713 ± 1280 €/km², 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.     

Sanitary risks of red-legged partridge releases: introduction of parasites

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.     

Game managers’ views on the release of farm-reared red-legged partridges in hunting estates within central Spain

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.     

Effect of Game Management on Wild Red-Legged Partridge Abundance

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 post-breeding 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.     

Hunting management in relation to profitability aims: red-legged partridge hunting in central Spain

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 socioeconomic 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.     

Harvest of red-legged partridge in central Spain

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. © 2012 The Wildlife Society.     

Mitochondrial DNA and microsatellite markers evidence a different pattern of hybridization in red-legged partridge (Alectoris rufa) populations from NW Italy

Genetic introgression with exotic genomes represents a major conservation concern for the red-legged partridge (Alectoris rufa, Phasianidae). In particular, massive releases of chukar partridges (Alectoris chukar) and/or red-legged × chukar partridge hybrids for hunting purposes have cast serious doubts on the Italian present-day occurrence of wild A. rufa populations not affected by introgressive hybridization. This study investigates the genetic structure of red-legged partridges populations in two ecologically different areas in Northern Italy. Analysis of maternal mitochondrial DNA and biparental microsatellite markers excluded the presence of hybridization in a typical agricultural habitat where hunting and release of reared birds are strictly banned. By contrast, signs of chukar introgression were detected in a perifluvial habitat unusual for the red-legged partridge in Italy. The present study documents the first red-legged partridge population with no genetic evidences of recent chukar introgression presently living in Italy. We recommend that urgent conservation actions are taken to preserve the genetic integrity of this population from the risk of hybridization with farm-reared birds and to support its long-term conservation.     

The effects of fasting and refeeding on biochemical parameters in the red-legged partridge (Alectoris rufa)

Every year, about three million farm-reared red-legged partridges are released in Spain for hunting purposes, most of them for restocking where the success is very low. Some factors such as the sudden shift from abundant commercial energy-rich diet to natural food and absence of experience at looking for natural food resources could cause a rapid physical deterioration, being more vulnerable to predation and disease. To determine fasting capacity in red-legged partridges, we fasted 32 birds during 4 days and then we refed them, collecting blood samples and body masses during the experiment. Red-legged partridges entered in the third critic phase of fasting, in which body proteins became the main energetic source, after 48 h of fasting. The fasting period caused an average loss of 17% of their initial body mass and only attained a 93.6% of their initial body mass after 24 days of refeeding. The limited capacity to resist fasting in the red-legged partridge could be one of the reasons for the low success in restocking, mainly in those where neither supplementary feeding nor acclimation period is allowed for birds before they are finally released.     

Are reclamo hunting seasons for the Spanish red-legged partridge off the mark?

The red-legged partridge (Alectoris rufa) is abundant in a number of regions in Spain and one of the most commonly hunted small game species in the country. Partridge hunting generates substantial income in rural areas where agriculture is less profitable. A traditional hunting method, reclamo hunting, is currently under revision by the European Commission's (EC) Birds Directive because hunting may fall within the reproduction period of the species. So far, only limited data on the reproductive phenology of the species exist to inform a policy change. In this study, we present reproduction data for red-legged partridges from 9 hunting estates in Andalusia during 1 year, and over 3 consecutive seasons from a control estate. We used direct nest and partridge chick covey observations to estimate 165 egg-laying dates. We found significant differences between sites related to altitude during reproduction periods. Using our pooled data, we showed that reproduction occurred between the last 10 days in January and the middle of February; beyond 31 January we observed an exponential increase in birds reproduction. According to these data and current EC legislation, reclamo hunting should not extend beyond 31 January. © 2012 The Wildlife Society.     

Prevalence of Escherichia coli, Salmonella sp. and Campylobacter sp. in the intestinal flora of farm-reared, restocked and wild red-legged partridges (Alectoris rufa): is restocking using farm-reared birds a risk?

For hunting purposes, several millions of red-legged partridges (Alectoris rufa) are released each year in Spain, and these releases have the potential to introduce new parasites and disease into wild populations. We studied the prevalence of Escherichia coli, Campylobacter sp. and Salmonella sp. in the intestinal flora of red-legged partridges from three different husbandry groups: farm-reared, restocked and natural populations. Prevalence of E. coli was significantly higher in farm-reared (45%, p = 0.01) and restocked partridges (60%, p < 0.001) than in wild ones (6%, p > 0.05). The prevalence of Campylobacter sp. (23%, 100 out of 444) did not differ significantly between these three husbandry groups, and Salmonella sp. was only detected in a group of partridge chicks on one of the farms studied (0.9%, 5 out of 544). These results suggest that farm-reared and restocked partridges can act as carriers of these three enteropathogens and highlight a potential risk of transmission to natural populations via the releases of farm-reared partridges. However, future investigations are needed regarding the relation of the isolated bacteria with zoonotic strains and dissemination of antibiotic resistant microorganisms, especially E. coli, and to better evaluate the effect that these three enteropathogens have on partridge health and on the success of restocking with farm-reared birds.     

Fitness consequences of anthropogenic hybridization in wild red-legged partridge (Alectoris rufa, Phasianidae) populations

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.     

Land use and environmental factors affecting red-legged partridge (Alectoris rufa) hunting yields in southern Spain

The red-legged partridge is a small game species widely hunted in southern Spain. Its commercial use has important socioeconomic effects in rural areas where other agrarian uses are of marginal importance. The aims of the present work were to identify areas in Andalusia (southern Spain) where game yields for the red-legged partridge reach high values and to establish the environmental and land use factors that determine them. We analysed 32,134 annual hunting reports (HRs) produced by 6,049 game estates during the hunting seasons 1993/1994 to 2001/2002 to estimate the average hunting yields of red-legged partridge in each Andalusian municipality (n=771). We modelled the favourability for obtaining good hunting yields using stepwise logistic regression on a set of climatic, topographical, land use and vegetation variables that were available as digital coverages or tabular data applied to municipalities. Good hunting yields occur mainly in plain areas located in the Guadalquivir valley, at the bottom of Betic Range and in the Betic depressions. Favourable areas are related to highly mechanised, low-elevation areas mainly dedicated to intensive dry crops. The most favourable areas predicted by our model are mainly located in the Guadalquivir valley.     

New data on mortality,home range,and dispersal of red-legged partridges (Alectoris rufa) released in a mountain range

We tested the success, dispersal, and home range of 20 radio-tagged farm-reared red-legged partridges that were released into typical Mediterranean scrubland on a coastal mountain in southern Spain. Partridges were kept in two acclimatization pens separated by 1 km for 4 weeks. Mortality was 25% during the first 10 days, 51.9% at the end of the second month, and stopped by the 14th week after release. The overall survival rate was 20.6%. Mean dispersal distance was 832 m; home range (MPC 95%), 16.6 ha; and activity centers (Kernel 60%), 15.1 ha. Two released females paired with wild males and one of them successfully nested.     

A note on the effectiveness of incorporating management objectives with ecological variables when modeling red deer abundance

Big game populations are being raised in areas characterized by different land uses and are being managed under a wide range of circumstances which might influence their population densities and structure. However, the consideration of explanatory variables related to management activities is not generally explicitly considered in game population models. This paper focuses on how estate owners’ management objectives and strategies influence red deer (Cervus elaphus L.) hunting yields. We study red deer harvest in 187 hunting estates in Andalusia (Spain) and use both ecological and management predictors to describe capture levels in each hunting estate. We have found that the main land use of the area where red deer are being raised, the type of hunting holder, and the long-term management strategies (such as fencing and the hunting practices implemented) significantly explain red deer hunting bag, which is often used as proxy of population abundance. Therefore, ecological variables alone are not always sufficient to determine big game harvests. We provide empirical support that reinforces the relevance of considering humans and their long-term decisions when trying to interpret wildlife harvests, populations, and trends. We urge scientists and technicians to incorporate human aims in the game species distribution models and resource user decision models, particularly when game populations are being intensively managed.     

Predator abundance in relation to small game management in southern Portugal: conservation implications

The interaction between hunting interests and legally protected predators is often a contentious conservation problem, requiring detailed understanding of predator responses to game management. This issue was addressed in southern Portugal in a treatment-control natural experiment, whereby the abundances of small game, corvids, birds of prey and carnivores were compared in 12 game estates (>500 ha) and 12 matching areas with similar sizes and land uses but no game management. European rabbits (Oryctolagus cuniculus), Iberian hares (Lepus granatensis) and, less so, red-legged partridges (Alectoris rufa) were far more numerous in game estates than elsewhere. Among legally controlled species, there were less Eurasian jays (Garrulus glandarius) but more red foxes (Vulpes vulpes) in game estates, though the latter were primary targets of predator culling. Fox abundance within game estates varied inversely with an index of management intensity (density of small game feeding sites) and increased along with hare abundance. As for protected species, only common kestrels (Falco tinnunculus) and genets (Genetta genetta) were fewer in game estates. The abundance of raptors within game estates varied inversely with gamekeeper density, whereas that of common buzzards (Buteo buteo) increased along with rabbit abundance. Overall, there was little evidence that game management reduced local predator abundances, except in the most intensively managed estates. Game estates provided concentrations of prey that was scarce elsewhere, which may have favoured increased abundances of some predators. Further investigations are needed to find out whether high prey densities may attract predators to game estates with increased mortality risk, which may thus become population sinks for protected species.     

Are farm-reared quails for game restocking really common quails (Coturnix coturnix)?: a genetic approach

The common quail (Coturnix coturnix) is a popular game species for which restocking with farm-reared individuals is a common practice. In some areas, the number of released quails greatly surpasses the number of wild breeding common quail. However, common quail are difficult to raise in captivity and this casts suspicion about a possible hybrid origin of the farmed individuals from crosses with domestic Japanese quail (C. japonica). In this study we used a panel of autosomal microsatellite markers to characterize the genetic origin of quails reared for hunting purposes in game farms in Spain and of quails from an experimental game farm which was founded with hybrids that have been systematically backcrossed with wild common quails. The genotypes of these quail were compared to those of wild common quail and domestic strains of Japanese quail. Our results show that more than 85% of the game farm birds were not common quail but had domestic Japanese quail ancestry. In the experimental farm a larger proportion of individuals could not be clearly separated from pure common quails. We conclude that the majority of quail sold for restocking purposes were not common quail. Genetic monitoring of individuals raised for restocking is indispensable as the massive release of farm-reared hybrids could represent a severe threat for the long term survival of the native species.     

Experimental evaluation of live cage-traps for black-billed magpies Pica pica management in Spain

Black-billed magpies (Pica pica) are considered as a nest predator of game and non-game birds in Europe. In rural areas of Spain magpie control is commonly used as a management tool in small game hunting estates. Cage-traps with a magpie as a decoy are the legal method most commonly used for controlling magpies in Spain although its performance has not yet been experimentally tested. We evaluated the selectivity, efficiency, and the effect of different factors on capture rate of these traps for magpie control and determine the effect of magpie removal on magpie density. Only four out of 197 captures corresponded to non-target species, which were released unharmed. Since the release of non-target captures depends on the daily checking of the trap and the trapper commitment, in order to guarantee the efficiency and selectivity of this method traps should be revised daily by full time, qualified trappers. The efficiency of this method is high during the breeding season, reducing magpie density in the area where the control is performed. Highest capture rates were obtained in the first days after cage-traps setting. Neither the gender nor the origin (local or foreign) of the decoy significantly affected the capture rate. Among male decoys, experimentally increased testosterone levels did not increase capture rates. According to our results, the tested cage-traps with a living decoy could be employed as an efficient and selective method for magpie population management in Spain, when used by full time, qualified trappers.     

Correlates of helminth community in the red-legged partridge (Alectoris rufa L.) in Spain

Between 1992 and 1996, 587 wild red-legged partridges (Alectoris rufa) from 16 Spanish provinces were examined to study the variations of helminth communities in this game species across a broad geographical area. The survey revealed 13 species of helminth parasites. Dicrocoelium sp.. Rhabdometra nigropunctata, and Cheilospirura gruweli were the most common species, whereas Raillietina bolivari, Choanotaenia infundibulum, Tetrameres sp., and Capillaria anatis were the most rare. Subulura suctoria, Heterakis gallinarum, Heterakis tenuicaudata, Capillaria contorta, Trichostrongylus tenuis, and Raillietina tetragona occurred with intermediate frequencies. The abundance of C. gruweli, S. suctoria, H. tenuicaudata, T. tenuis, and R. tetragona was inversely correlated to latitude and directly correlated to yearly mean temperature, whereas the abundance of Dicrocoelium sp. was directly correlated to latitude and inversely correlated to yearly mean temperature. The abundance of R. tetragona was inversely correlated to latitude and yearly mean humidity. The number of helminths per partridge and the number of helminth species per partridge were lower in young birds than in adults. Partridge body condition was inversely correlated to abundance of C. contorta. Richer infracommunities were linked to richer component communities. At the infracommunity level, total number of helminths per partridge and number of helminth species per partridge were inversely correlated to latitude and directly correlated to yearly mean temperature. At the component community level, both species richness and diversity (Simpson's index) were inversely correlated to latitude and directly correlated to mean temperature. Across the broad geographical range of the study area, the helminth parasite communities of red-legged partridges had marked geographical variation in their structure. Our results suggest that this variation is determined by the distribution of both intermediate and definitive hosts. We discuss the implications of this variation for the hypothesis that supplementary releases of captive-bred partridges for sport hunting can affect the helminth fauna of wild red-legged partridges.     

<Emphasis Type="Italic">Mycobacterium avium</Emphasis> disease in wild red-legged partridges (<Emphasis Type="Italic">Alectoris rufa</Emphasis>)

Three wild red-legged partridges (Alectoris rufa) from intensively managed hunting areas in Spain were received for necropsy. They showed granulomatous lesions in different parts of the body, mainly in liver and spleen. Microscope examination of the granulomas showed central caseous necrosis and large amounts of acid-fast bacilli, surrounded by epitheloid cells, giant cells, and lymphocytes. Attempts to isolate and culture the bacillus in Colestsos medium were unsuccessful, but the polymerase chain reaction technique revealed the presence of microorganisms belonging to the Mycobacterium avium complex in one of the partridges. This is the first report of avian tuberculosis in free-living red-legged partridges.     

Predation of simulated red-legged partridge nests in big game estates from South Central Spain

Over the past few decades, the wild boar has been undergoing an expansion in Europe, which may have negatively affected small game populations and particularly red-legged partridges. We aim to evaluate the red-legged partridge nest predation by wild boar at high boar abundances by placing artificial nests in nine big game estates. Predation rates were compared between nests placed in fenced controlled plots with no wild boar access (but accessible to other predators) and open plots in which the wild boar gains access. The proportion of nests and eggs predated was significantly lower in wild boar exclusion areas, recording a predation rate of 50 % for the nests and 38 % for the eggs in these areas, whereas in the presence of wild boar, the predation rate was 80 % for the nests and 58 % for the eggs. Moreover, the wild boar was identified as the main nest predator in unfenced areas, accounting for 36 and 48 % of the predated nests and eggs respectively. This study sheds light on the wild boar predation on nests of the red-legged partridges.