Alectoris Rufa Research Articles

Ocellated lizard predation patterns on red-legged partridge nests in olive groves

In this study, we evaluated predation of the ocellated lizard on red-legged partridge nests in an olive grove in southern Spain over three consecutive years. The microhabitat characteristics of prey nests are analysed through comparison with successful nests. We found only 13 nests predated by lizards during the study period. This number was three times lower than that of nests that failed due to causes related to agricultural practices or human activity in the same period and study area. A few of the nests were predated by mammals more than they were preyed upon by lizards. The nests preyed on by lizards were associated with proximity to their refuge areas (e.g. stone piles, old buildings with holes, or rabbit burrows). The characteristics of the olive grove (e.g. drip irrigation and absence of vegetation under the olive trees) may favour the ocellated lizards' search-and-hunt strategy, which allows a lizard to readily find a nest if it is inside the lizard's territory and close to its refuge. We propose management strategies for reducing lizard-related nest losses. However, we argue that olive grove intensification is a major cause of partridge nest failure rather than predation by lizards and other predators.

A non-invasive method to monitor farmland bird exposure to triazole fungicides

The treatment of seeds with pesticides is an extended practice in current agriculture. There is a high risk of exposure in granivorous birds, such as the red-legged partridge (Alectoris rufa), that can consume those seeds remaining on the surface during sowing. Fungicide exposure could in turn affect bird reproductive capacity. To better understand to what extent triazole fungicides are a threat to granivorous birds, we need an easy and reliable method to quantify field exposure. In this study, we tested a novel non-invasive method to detect the presence of triazole fungicide residues in farmland bird faeces. We experimentally exposed captive red-legged partridges to validate the method, and then applied it in a real scenario to assess exposure of wild partridges. We exposed adult partridges to seeds treated with two formulations containing triazole fungicides as active ingredients: Vincit®Minima (flutriafol 2.5%) and Raxil®Plus (prothioconazole 25% and tebuconazole 15%). We collected two types of faeces (caecal and rectal samples) immediately after exposure and 7 days later and quantified the concentrations of the three triazoles and their common metabolite (1,2,4-triazole). The three active ingredients and 1,2,4-triazole were only detected in faeces collected immediately after exposure. Triazole fungicide detection rates in rectal stool were 28.6%, 73.3% and 80% for flutriafol, prothioconazole and tebuconazole, respectively. In caecal samples, detection rates were 40%, 93.3% and 33.3%, respectively. 1,2,4-triazole was detected in 53% of rectal samples. For an applied use of the method in the field, we collected 43 faecal samples from wild red-legged partridges during autumn cereal seed sowing and found detectable levels of tebuconazole in 18.6% of the analysed wild partridges. The results of the experiment were then used to estimate actual exposure levels from this prevalence value found in wild birds. Our study shows that faecal analysis can be a useful tool to assess farmland bird exposure to triazole fungicides, when samples are fresh and the method has been validated for the detection of target molecules.

Genomic diversity and signals of selection processes in wild and farm-reared red-legged partridges (Alectoris rufa)

The genetic dynamics of wild populations with releases of farm-reared reinforcements are very complex. These releases can endanger wild populations through genetic swamping or by displacing them. We assessed the genomic differences between wild and farm-reared red-legged partridges (Alectoris rufa) and described differential selection signals between both populations. We sequenced the whole genome of 30 wild and 30 farm-reared partridges. Both partridges had similar nucleotide diversity (π). Farm-reared partridges had a more negative Tajima's D and more and longer regions of extended haplotype homozygosity than wild partridges. We observed higher inbreeding coefficients (FIS and FROH) in wild partridges. Selective sweeps (Rsb) were enriched with genes that contribute to the reproductive, skin and feather colouring, and behavioural differences between wild and farm-reared partridges. The analysis of genomic diversity should inform future decisions for the preservation of wild populations.

Understanding the impact of wild boar on the European wild rabbit and red-legged partridge populations using a diet metabarcoding approach

European wild rabbit (Oryctolagus cuniculus) and red-legged partridge (Alectoris rufa) are main small game species of conservation concern in Mediterranean ecosystems. To date, their presence in wild boar’s (Sus scrofa) diet and factors driving their consumption have been little investigated. A genetic metabarcoding approach was used on 80 wild boar faeces collected from four hunting estates devoted to small game hunting during two different seasons. Abundances of wild boar, rabbits and partridges were first estimated. Results showed DNA of seventeen chordate species. The highest frequency of occurrence (FO) corresponded to mammals and birds, with 77.6 and 22.3%, respectively. DNA of game species was detected in 39/71 (FO = 55.0%) samples, highlighting the presence of European wild rabbit in 27 (FO = 38.0%) and red-legged partridge in eight (FO = 11.3%). Dietary composition varied between seasons and estates, being rabbit the main responsible (explaining 35.26% and 39.45% of differences, respectively). Rabbit FO in the diet was positively related to the abundance of wild boar and rabbit density on the estate. It was greater in autumn and in estates where rabbits were hunted. Regarding red-legged partridge, a significant and positive relationship between its population density and its diet FO was observed, without significant differences between seasons or estates. Overall, our results suggest wild boar as an opportunistic species whose diet is largely determined by the relative availability of different food resources. Its ecological role concerning small game species in Mediterranean agroecosystems seems to be more related to consumption of carrion during the hunting season than to direct predation.

Genome Characterization and Spaciotemporal Dispersal Analysis of Bagaza Virus Detected in Portugal, 2021

In September 2021, Bagaza virus (BAGV), a member of the Ntaya group from the Flavivirus genus, was detected for the first time in Portugal, in the heart and the brain of a red-legged partridge found dead in a hunting ground in Serpa (Alentejo region; southern Portugal). Here we report the genomic characterization of the full-length sequence of the BAGV detected (BAGV/PT/2021), including phylogenetic reconstructions and spaciotemporal analyses. Phylogenies inferred from nucleotide sequence alignments, complemented with the analysis of amino acid alignments, indicated that the BAGV strain from Portugal is closely related to BAGV strains previously detected in Spain, suggesting a common ancestor that seems to have arrived in the Iberia Peninsula in the late 1990s to early 2000s. In addition, our findings support previous observations that BAGV and Israel turkey meningoencephalitis virus (ITV) belong to the same viral species.

Effect of midazolam sedation on sperm quality in capercaillie, following a protocol developed in chicken and partridge as model

Animal capture is essential in conservation and management programs, both for captive and wild species. This paper describes the effect of midazolam sedation in domestic and wild phasianids with respect to dorso-abdominal massage for obtaining semen samples, and on the quality of the sperm thus collected. Three experiments were performed. Experiment 1 - Determination, with respect to semen quality, of the optimum midazolam treatment for sedation in the domestic chicken. This involved sedating birds with either: 1) 2 mL of saline (control [C]), 2) 2 mg/kg of midazolam (low dose [LD]), 3) 6 mg/kg of midazolam (high dose [HD]), or 4) 6 mg/kg of midazolam and waiting 10 min before starting to massage (HD-10) (all performed in duplicate). The response time to the sedative (T1) was recorded, as were the times from the start of massage to ejaculation (T2) and its end (T3). The proportion of animals that showed stress during massage was noted via their waking, wing flapping, and the heterophil-lymphocyte ratio. The volume of all sperm samples obtained was determined, along with sperm concentration, motility, viability, and DNA integrity. Experiment 2 - The same determinations were made in captive red-legged partridges. Experiment 3 - The effect of the discovered optimum conditions (HD-10) for the above species was examined in the capercaillie (a wild species). Sperm quality was not affected by sedation with midazolam in any of the examined species, although the capercaillies and partridges were more nervous during semen collection than were the chickens.

Unexpected genetic integrity boosts hope for the conservation of the red-legged partridge (Alectoris rufa, Galliformes) in Italy

The red-legged partridge (Alectoris rufa) is a medium-sized galliform endemic to southwestern Europe. In the easternmost part of the species’ range, the population inhabiting Elba Island (Tuscan Archipelago National Park, Italy) is of undisputed conservation value. While we found nuclear and maternal DNA introgression with the exotic chukar partridge (A. chukar) in previous studies based on microsatellite DNA (n = 25) and two mitochondrial markers (n = 103), respectively, we disclosed a limited or null admixture in a few Elban partridges (n = 4) in a recent genomic investigation relying on 168,675 Single Nucleotide Polymorphisms (SNPs). We herein carried out an extended microsatellite DNA survey including additional 65 samples (total, 90) and six loci (total, 11) to determine both spatial structure and genetic integrity of local A. rufa. A sharp divergence between the subpopulations inhabiting the two sides of the island was disclosed, and the microsatellites indicated that all Elban partridges were not admixed with the chukar, thus fully reflecting the picture inferred using SNPs. We hypothesized that the spreading of chukar genes was constrained by negative selection, with the persistence of only the maternal lineage being indicative of thermal adaptation. The two subpopulations should be treated as distinct Management Units, and an envisaged plan to secure a stock onto nearby Pianosa Island could not only warrant endurance of the Elban population but also establish a source of valuable founders for the ex-situ management of the species in Italy. Our study exemplifies how a suitable samples/loci combination is the key to solve wildlife issues dealing with introgression.

The Quail Game Farming Sector in Spain.

Quail (Coturnix genus) game farms were characterised in Spain using variables related to their age, geographical distribution, farmed species, structure, size, and commercialisation, using a survey conducted on 21 farms in 2018. It was found that 38.1% of the sample represented complete-cycle farms, and 61.9%, which have no breeding flocks, undertook only the finishing phase of quail raising. The average size of the breeding flock, with regard to complete-cycle farms, was 1096 males and 3735 females, with a female/male ratio of 3.6, and 75% of these farms carried out self-replacement of breeding quails. The most farmed species was European quail (Coturnix coturnix), followed by Japanese quail (Coturnix japonica), and hybrids of both species. In addition to quail, all farms produced other gamebird species such as pheasant (Phasianus colchicus) and red-legged partridge (Alectoris rufa). The rearing phase, which began when the chicks were one-day-old, lasted 35.3 days on average (range: 25-49 days), with an average stocking density of 47.2 birds/m2 in the brooder house. The finishing phase, which was carried out in flying pens at a stocking density of 9.5 birds/m2, ended when the quails' average age was 60.5 days. All farms sold quails for release in hunting reserves (EUR 1.54 per bird) and for dog training (EUR 1.65 per bird) for almost 10 months of the year; only 62% sold quails for shooting after being thrown with an adapted clay-pigeon shooting machine (EUR 1.49 per bird). Transporting quails to their destination (95.2% of the farms) and releasing the birds in the client's hunting preserve (52.4% of the farms) were services offered by the farms, among others. The main advertising and promotional strategies undertaken by the quail game farms to gain a share of the market included maintaining a business website (85.7% of the farms) and attending game and agricultural fairs (47.6% of the farms). In conclusion, this alternative poultry sector has been consolidated in Spain, five decades since the establishment of the first game farms, and it satisfies a relevant part of the demand for quail hunting.

The predation of hatching Red-legged Partridges Alectoris rufa by the harvester ant Messor barbarus

ABSTRACT We report, for the first time, two cases of predation on Red-legged Partridge Alectoris rufa chicks in the process of hatching by the harvester ant Messor barbarus.

Bagaza virus and Plasmodium spp. coinfection in red-legged partridges (Alectoris rufa), in Southern Spain 2019.

Flaviviruses such as West Nile (WNV), Usutu (USUV) and Bagaza (BAGV) virus and avian malaria parasites are vector borne pathogens that circulate naturally between avian and mosquito hosts. WNV and USUV and potentially also BAGV constitute zoonoses. Temporal and spatial cocirculation and coinfection with Plasmodium spp., and West Nile virus has been documented in birds and mosquito vectors, and fatally USUV-infected passerines coinfected with Plasmodium spp. had more severe lesions. Also, WNV, USUV and BAGV have been found to cocirculate. Yet little is known about the interaction of BAGV and malaria parasites during consecutive or coinfections of avian hosts. Here we report mortality of free-living red-legged partridges in a hunting estate in Southern Spain that were coinfected with BAGV and Plasmodium spp. The outbreak occurred in the area where BAGV first emerged in Europe in 2010 and where cocirculation of BAGV, USUV and WNV was confirmed in 2011 and 2013. Partridges were found dead in early October 2019. Birds had mottled locally pale pectoral muscles, enlarged, congestive greenish-black tinged livers and enlarged kidneys. Microscopically congestion and predominantly mononuclear inflammatory infiltrates were evident and Plasmodium phanerozoites were present in the liver, spleen, kidneys, muscle and skin. Molecular testing and sequencing detected Plasmodium spp. and BAGV in different tissues of the partridges, and immunohistochemistry confirmed the presence and colocalization of both pathogens in the liver and spleen. Due to the importance of the red-legged partridge in the ecosystem of the Iberian Peninsula and as driver of regional economy such mortalities are of concern. Such outbreaks may reflect climate change related shifts in host, vector and pathogen ecology and interactions that could emerge similarly for other pathogens.

Gastrointestinal parasites in red-legged partridges (Alectoris rufa) hunted in Spain: a warning to game managers

Red-legged partridge (Alectoris rufa) populations are currently declining in the Iberian Peninsula, mainly due to habitat degradation and hunting pressure. In addition, the release of farm-reared partridges may introduce pathogens, including parasites, to wild populations. The presence of digestive parasites in red-legged partridges hunted in fifteen Spanish provinces was studied. Fecal samples and gastrointestinal tracts were collected, analyzed, and the morphometric identification of parasites was carried out. Eimeria spp. oocysts, nematode, cestode and trematode eggs were observed in fecal samples. Adult nematodes (Ascaridia galli, Ascaridia compar, Heterakis gallinarum, Heterakis tenuicauda, Trichostrongylus tenuis, Subulura spp., Cyrnea spp. and Aonchotheca caudinflata), tapeworms (Raillietina tetragona, R. echinobothrida, R. micracantha, Rhabdometra nigropunctata, and Choanotaenia infundibulum), and trematodes (Brachylaima spp., Brachylecithum spp., Dicrocoelium spp.) were identified in the gastrointestinal tracts. Significant statistical differences were found among climatic regions in the prevalence and intensity of Eimeria spp. infection, median intensity and the prevalence of indirect life cycle helminths, with Southern areas always showing higher infection values. The study provides information of the health status of red-legged partridges in Spain, highlighting the risk associated with the release of farm-reared partridges for restocking purposes. This should be taken into account to improve management strategies for the long-term conservation of the species.

Bagaza Virus in Wild Birds, Portugal, 2021.

Bagaza virus emerged in Spain in 2010 and was not reported in other countries in Europe until 2021, when the virus was detected by molecular methods in a corn bunting and several red-legged partridges in Portugal. Sequencing revealed high similarity between the 2021 strains from Portugal and the 2010 strains from Spain.

Effects of Sibling Eggs Contact on Incubation Length and Hatching Synchrony in Red-Legged Partridge (Alectoris rufa)

Hatching synchrony is a desirable trait in the artificial incubation of eggs because it permits the simultaneous extraction of all the chicks from the hatcher, thus minimizing extraction queues. This study aimed at evaluating the effects on egg performance, incubation length, and hatching synchrony of different sibling contact regimes during the incubation in red-legged partridge (Alectoris rufa) eggs. To achieve these objectives, 196 eggs were arranged in four treatments according to the sibling eggs contact regime: (a) eggs without contact during the whole incubation process; (b) eggs in contact during the incubation phase (from day 1 to 20 of incubation); (c) eggs in contact during the hatching phase (from day 20 of incubation to hatching); (d) eggs in permanent contact throughout the incubation process (from day 1 of incubation to hatching). Development stage at embryonic mortality, hatchability, and egg weight loss during incubation were not affected, but incubation length was shortened and hatching synchrony was increased in eggs in contact during the hatching phase. The main conclusion was that keeping red-legged partridge eggs in close contact during the hatching stage in the artificial incubation does not affect hatchability but allows hatching synchrony to be maximized, facilitating the handling of 1 day old chicks.

The Impact of Pb from Ammunition on the Vegetation of a Bird Shooting Range

Hunting with lead ammunition represents a source of heavy metal pollution to the environment that can be potentially high at the local scale. Intensive hunting of small game species can concentrate high levels of ammunition discharging in small areas. This type of hunting is a relevant economic resource for private landowners in some regions of Spain, and current legislation allows the use of lead ammunition in these scenarios. It becomes, therefore, highly relevant to study whether this activity may pose concerns to the conservation of the environment in the areas where it takes place. Using a red-legged partridge (Alectoris rufa) shooting range as a study area, we examined the effect of intensive hunting on this species on the vegetation present. We found significantly higher lead levels in the sprouts of plants of shooting areas related to control sites of the same property where partridge shooting does not occur. We found differences in the presence of lead between sprouts of different plant species. In addition, old sprouts of existing vegetation in shooting areas also showed higher lead levels than newly emerged sprouts of the same plants. These results demonstrate the impact of lead ammunition on vegetation in terms of persistence over time and differences between species. Further analyses using chemical and ecotoxicological data are necessary to evaluate the extent of environmental pollution risks. Our results provide new support in favor of the use of alternative ammunition, with particular emphasis on scenarios where hunting activity is intensive.

Alectoris rufa (red-legged partridge)

This datasheet on Alectoris rufa covers Identity, Overview, Distribution, Further Information.

Risk of Infection, Local Prevalence and Seasonal Changes in an Avian Malaria Community Associated with Game Bird Releases

Anthropogenic activities, such as the translocation or introduction of animals, may cause a parallel movement of exotic parasites harboured by displaced animals. Although introduction and/or relocation of animals for hunting purposes is an increasingly common management technique, the effects of gamebird release as a major vehicle for the introduction of parasites into new geographic regions have rarely been reported. We examined the prevalence and distribution of avian malaria parasites infecting resident avian hosts (red-legged partridge Alectoris rufa) at a local scale, with a particular emphasis on the effects of releasing farm-reared birds for hunting on the spatial and temporal structure of the parasite community. We collected blood samples from adult partridges from two game estates with partridge releases and two sites without releases over two periods (spring and autumn). We tested the probability of infection and differences in the parasite community in relation to the management model (releases vs. non releases) and sampling period, comparing autumn (when farm-reared birds are released) and spring (after hunting season, when mostly wild birds can be found in the population). We found a high prevalence (54%) of Plasmodium spp., and substantial differences in the spatial and temporal distribution of parasite lineages among the populations studied. Some parasite lineages occurred at high frequencies in game estates without introduction of farm-reared partridges, while other lineages were more abundant in game estates with releases than in those without releases. Overall, the prevalence of avian malaria was similar between spring and autumn at non-release sites, whereas in sites with releases, it was higher in autumn than in spring—probably due to artificial restocking with infected farm-reared birds at the onset of the hunting season. In short, humans may be an important agent driving the alteration of the spatial structure of local parasite fauna via the introduction of exotic parasites by gamebird release, which could cause avian malaria outbreaks with severe repercussions for native avifauna.

Metabarcoding insights into the diet and trophic diversity of six declining farmland birds

Knowledge of feeding ecology of declining species, such as farmland birds, is essential to address their conservation requirements, especially when their habitats are suffering important reductions of trophic resources. In this study, we apply a metabarcoding approach to describe the diet composition of six of the most significant farmland birds inhabiting European cereal pseudo-steppes: little bustard, great bustard, pin-tailed sandgrouse, black-bellied sandgrouse, red-legged partridge, and common quail. We further studied seasonal diet variations (autumn to spring) in all species but the common quail, whose diet was studied during spring and summer. We show that study species´ diets mostly consisted of plants, although in the case of little bustard and great bustard arthropods are also highly relevant. Among arthropods, we found high proportions of thrips, arachnids, and springtails, which were previously unreported in their diet, and some taxa that could be used as antiparasitic food. Moreover, we report that little bustard’s diet is the least rich of that of all studied species, and that diet of all these species is less diverse in winter than in autumn and spring. Diet composition of these declining species supports the importance of natural and semi-natural vegetation and landscape mosaics that can provide a wide variety of arthropods, plants, and seeds all year-round.

Bird exposure to fungicides through the consumption of treated seeds: A study of wild red-legged partridges in central Spain

Sown seeds are a key component of many farmland birds’ diets due to natural food shortages in autumn and winter. Because these seeds are often treated with pesticides, their ingestion by birds can result in toxic effects. For risk assessment, data on treated seed toxicity should be combined with information about exposure risk for wild birds and the factors that modulate it. We characterized the exposure of red-legged partridges to pesticide-treated seeds through the analysis of digestive contents of birds shot by hunters (n = 194) in an agricultural region in central Spain. We measured the contribution of sown seeds to the partridges' diet and how it related to pesticide exposure. Moreover, we evaluated the influence of landscape composition on the intake of sown seeds and pesticides by partridges. During peak sowing time, seeds constituted half (50.7%) of the fresh biomass ingested by partridges, which consumed mostly winter cereal seeds (42.3% of biomass). Residues of seven fungicides and one insecticide (active ingredients) were detected in 33.0% of birds. The presence of pesticides in digestive contents was linked to the ingestion of cereal sown seeds. Moreover, dietary exposure of birds to pesticides was modulated by landscape characteristics, being lower in areas with heterogeneous landscapes, greater habitat mosaic and more natural vegetation. The estimated dietary intake of pesticides resulting from our field observations, in combination with experimental data on pesticide toxicity, raise concerns about the risks that pesticide-treated cereal seeds pose to granivorous bird populations. Our results highlight the importance of farming landscape composition and diversification, which should be considered as a priority in the agricultural policy to mitigate pesticide risks to farmland birds through the consumption of treated seeds.

Novel genome reveals susceptibility of popular gamebird, the red-legged partridge (Alectoris rufa, Phasianidae), to climate change

We produced a high-quality de novo genome assembly of the red-legged partridge A. rufa, the first reference genome of its genus, by utilising novel 10× Chromium technology. The estimated genome size was 1.19 Gb with an overall genome heterozygosity of 0.0022; no runs of homozygosity were observed. In total, 21,589 protein coding genes were identified and assigned to 16,772 orthologs. Of these, 201 emerged as unique to Alectoris and were enriched for positive regulation of epithelial cell migration, viral genome integration and maturation. Using PSMC analysis, we inferred a major demographic decline commencing ~140,000 years ago, consistent with forest expansion and reduction of open habitats during the Eemian interglacial. Present-day populations exhibit the historically lowest genetic diversity. Besides implications for management and conservation, this genome also promises key insights into the physiology of these birds with a view to improving poultry husbandry practices.

Farmland composition and farming practices explain spatio-temporal variations in red-legged partridge density in central Spain

Many farmland bird populations are declining, and their negative trends are often associated with changes in land-use or farming practices, including the use of agrochemicals. The red-legged partridge (RLP) is a Mediterranean farmland game species of high socio-economic importance whose populations are thought to have declined sharply since the mid-20th century associated with farmland changes. However, no large-scale studies have tested whether abundance or trends of RLP are related to farmland composition or management.We used hierarchical distance sampling models to estimate RLP abundance in 2010 in central Spain (Castilla-La Mancha), a main European population stronghold of this species. We studied associations between RLP density and land-uses (including variation in management: irrigated crops or organic farming). We also assessed regional abundance variation over seven years (2010–2017) and its relationship with changes in land-use.Our results show that RLP abundance increased with the availability of natural vegetation and traditional rain-fed vineyards, but decreased with increasing proportions of tree crops and irrigated vineyards; the latter association was less pronounced in areas sensitive to nitrate contamination in water, where the amount of fertilizers applied in farmland and use of certain farming practices is more strictly regulated. These results support the idea that increases in intensive vineyards are detrimental to the RLP. We also report a strong population decline of RLP in the region, with a 51% abundance reduction in seven years. This decline was steeper in areas where more natural vegetation had been lost and where ecological tree crops had increased.Overall, our results indicate that changes in land-use (type of crop, or the destruction of natural vegetation in farmland) and farming practices (e.g. use of irrigation in certain crops, use of nitrates) have important impacts on this farmland bird, affecting both spatial distribution and population dynamics.