Wild Red-legged Partridge Research Articles

Metabarcoding reveals seasonal variations in the consumption of crops and weeds by wild Red-legged Partridge Alectoris rufa

Metabarcoding reveals seasonal variations in the consumption of crops and weeds by wild Red-legged Partridge Alectoris rufa

Age and Sex Ratios in a High-Density Wild Red-Legged Partridge Population.

The dynamics of a wild red-legged partridge population were examined over a 14-year period in Spain to identify patterns in age and sex ratios in relation to weather parameters, and to assess the importance of these parameters in population dynamics and management. The results gave age ratios of 1.07 (but 2.13 in July counts), juvenile sex ratios of 1.01 and adult sex ratios of 1.47. Overall, 12% more females were hatched and female juvenile mortality was 7.3% higher than in males. Sex differential mortality explains the 19.2% deficit in adult females, which are more heavily predated than males during the breeding period. Accordingly, age ratios are dependent on sex ratios and both are density dependent. Over time, ratios and density changes appear to be influenced by weather and management. When the habitat is well conserved, partridge population dynamics can be explained by a causal chain: weather operates on net primary production, thereby affecting partridge reproduction and predation and, as a result, age and sex ratios in the October population. A reduction in the impact of predation (i.e. the effects of ground predators on eggs, chicks and breeding females) is the key factor to improve the conservation of partridge populations and associated biological processes.

Gender-related amino acid intake of adult wild Red-legged Partridge (Alectoris rufa)

The Red-legged Partridge (Alectoris rufa) is under an enormous hunting pressure. It is bred intensively in game farms. The hunting season is during the non-reproductive resting period when partridges are at maintenance conditions.There is a lack of information about the amino acid (AA) composition of the natural diet of the adult birds in their habitat or differences in dietary AA composition related to gender. The objective of this work was to establish a first approach to the AA composition of the natural diet of adult wild Red-legged Partridge.Food content in crops and gizzards of female and male birds hunted in the same hunting season and area was analysed for AA composition.Females food had higher concentrations of individual essential AA (EAA) and non-essential AA (NEAA) than males.There are important differences in the concentration of AA in the natural diet of wild females and males. It may be advisable to use diets differing in the proportion of individual AA in the game farms during the non-reproductive resting period.

Are farm-reared red-legged partridge releases increasing hunting pressure on wild breeding partridges in central Spain?

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.

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.

Phenotypic differences in body size, body condition and circulating carotenoids between hybrid and “pure” red-legged partridges (Alectoris rufa) in the wild

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.

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.

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.

Isolation from predators: a key factor in the failed release of farmed red-legged partridges (Alectoris rufa) to the wild?

1. The effects of predation isolation were studied in two lines of 10 month-old farmed red-legged partridges (Alectoris rufa). Birds came from bred generations in captivity (F) and directly from wild parents (W). 2. Releases were carried out in March for two consecutive years on private farmland with a stable population of wild red-legged partridge using 68 tagged birds (36 F, 32 W). 3. No statistical differences were found in survival time (mean 18 d) or home range values (mean 7·38 ha); 49% of mortality was attributable to raptors, 36% to wild canids and 15% had doubtful causes of death. F birds suffered more predation by raptors and W partridges more by mammalian carnivores. 4. A statistical difference was found in post-release dispersion: the means were 243·4 m in F and 593·3 m in W. 5. The result of predation isolation was similar in both groups, which confirms the adverse effects of current production systems on anti-predator behaviour. Farmers should consider the introduction of new rearing techniques with the aim of improving survival after release.

Study of survival, dispersal and home range of autumn-released red-legged partridges (Alectoris rufa)

1. On a private property with a stable population of wild red-legged partridge (Alectoris rufa) and an appropriate habitat for the survival of the species, reinforcement repopulations were carried out in the months of October and November for two consecutive years using 5- to 6-month-old birds reared on a commercial game farm. 2. Of the 36 released birds, none was still alive by the following spring's breeding period. Mean survival time was 9·4 d in the first year and 7·6 d in the second year. 3. Seventy-two per cent of mortality was attributable to predation, 11% to hunting and 17% to doubtful causes of death, accidents and starvation. 4. Post-release mean dispersion was 377·8 m in the first year and 526·3 m in the second. Mean home range was 7·1 ha in the first year and 5·4 ha in the second. 5. The production systems and handling practices of commercial game farms may have modified some anti-predator ethological patterns and strategies, which might make it more difficult for the birds to adapt and integrate into the wild, resulting in reduced survival due to premature mortality.

Use of Radiotracking Techniques to Study a Summer Repopulation with Red-Legged Partridge (Alectoris Rufa) Chicks

On a private property with a stable population of wild Red-Legged partridge (Alectoris rufa) and an appropriate habitat for the survival of the species, reinforcement repopulations were carried out using 54 birds that were 2 to 3 mo old and reared on a commercial game farm. This study aimed to evaluate the effectiveness of repopulations, the behavior in the wild of released partridges, and the possible causes of success or failure of reinforcement population operations.The releases were carried out during August and September of 2 consecutive years. All birds were equipped with radio transmitter collars to determine their behavior after release. Two release methods were used in yr 1: an acclimatization cage (AC) method and a direct release method on the day of the birds arrival (DR). The aim of the release in yr 2 was to collect data to determine the influence of year conditions using the DR method.Of the 54 released birds, none remained alive by the time of the reproductive period in the following spring. The mean survival time was 16.79 d for the AC method and was 11.89 and 5 d for the DR method in yr 1 and 2, respectively. Of the recorded mortalities, we assigned 81.13% to predation, 7.55% to hunting, and 11.32% to unknown causes of death, accidents, or starvation. Repopulation was not successful at providing a long-term increase in partridge numbers, with most birds falling victim to predation within 1 mo of release. Dispersion is the maximum distance from the release point at which each bird was located. The postrelease mean dispersion was 437.65 m for the AC method and was 647.57 and 266.07 m for the DR method in yr 1 and 2, respectively.

Ectoparasite ticks and chewing lice of red-legged partridge, Alectoris rufa, in Spain.

During the 1992-1993 and 1993-1994 shooting seasons, 212 wild red-legged partridge, Alectoris rufa (Galliformes: Phaisanide) were captured in 18 Spanish provinces and examined for chewing lice and ticks. Three tick species and six species of chewing lice were found. Ticks (Acari: Ixodidae) Haemaphysalis punctata Canestrini & Fanzago, Hyalomma lusitanicum Koch and Ixodes frontalis Panzer were found at the lowest prevalence (1.4% overall tick prevalence). The louse (Mallophaga) species, Goniodes dispar Burmeister (Goniodidae) (52.8%) and Cuclotogaster obscurior Hopkins (Philopteridae) (28.8%) were the most prevalent, while Goniocotes obscurus Giebel (Philopteridae) (10.8%), Menopon pallens Clay (Menoponidae) (7.5%) and Menacanthus lyali Rodriguez et al. (Menoponidae) (3.3%) were found at medium to low prevalence. Columbicola columbae columbae Linnaeus (Philopteridae) was found at the lowest prevalence (0.5%). The intensity of C. obscurior and overall intensity of all lice species were directly related to the environmental mean temperature and the Normalized Difference Vegetation Index (NDVI), whereas intensity of G. dispar was directly related to NDVI only. The intensity of G. dispar, C. obscurior, all louse intensity, and louse species richness were higher in male than female birds. Intensity of each louse species, all louse intensity and louse species richness were inversely associated with the nutritional index. No relationship was observed between bird age and louse intensity or species richness.

Nesting type choice in the red-legged partridge (Alectoris rufa)

AbstractIn order to avoid the decrease in the numbers of wild red-legged partridge, Alectoris rufa, observed in several areas, the most appropiate solution is to repopulate using animals from game farms. The nesting place chosen by 30 pairs of red-legged partridge in captivity was studied. There were five different nest types combined in groups of three in 30 cages. Type A nest: made with natural bush plants tied together at one end and placed invertedly forming a cone. Type B: made with the same natural bush plants as the previous type but placed over an internal wire structure and having preformed entrances. Type C: a wooden structure in the form of a roof with two slopes. Type D: similar to the type C but on one of the laterals the opaque material only covers the upper half, and a plastic mesh covers the lower half. Type E: a wooden square box covered with an inclined plank of opaque and waterproof material. Our study shows that the type A nest received significantly (P < 0·05) more eggs than the others, possibly because this type of nest allowed for better vigilance and a better sense of protection for the animals. Type E nest was the second most preferred. In this type, the partridge was able to monitor the surroundings through the space between the walls and the roof and this space could be used as an escape route. From a production and industrial perspective, type E has some advantages over type A, being easy to build, clean and disinfect, and allowing the birds to see through the nest.