Alectoris Rufa Research Articles

Reproductive performance changes with age and laying experience in the Red‐legged Partridge Alectoris rufa

Most studies of birds have reported positive effects of ageing on reproductive traits during the first years of life followed by a decline. We examined the effects of age and laying experience, controlling for confounding factors such as food availability/quality and timing of pair formation in a captive population of Red‐legged Partridge Alectoris rufa. We found that all reproductive traits, except for the period between eggs, were highly repeatable within females both within and between years. The repeatability of egg mass was lower than that of clutch size, laying onset or chick traits other than the mass and size increase rates, perhaps suggesting a lower heritability value. As females aged, they showed a tendency to produce marginally lighter eggs (1.3%) and larger clutches, although this latter trend was not significant. We suggest that the senescence process implies the involvement of hormonal changes that could affect the reduction of egg mass (e.g. low levels of oestradiol). Younger females tended to start laying later than older females, which could be due to a low responsiveness to photoperiodic stimulation of the reproductive system, which would indicate a delay in gametogenesis and steroidogenesis. The mass of last‐laid eggs decreased with age of the female. We suggest that physiological changes through the laying sequence could vary with age. Experienced breeders laid larger clutches linked with the advancement of laying onset. For a given age, females with more experience fared better than those with less experience.

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.

Introgression of chukar genes into a reintroduced red‐legged partridge (Alectoris rufa) population in central Italy

Insight regarding the genetic origin and composition of the studied population of the red-legged partridge (Alectoris rufa) is likely to provide general and critical information for the appropriate management and possible conservation of the species. The reintroduced population of red-legged partridges living in Pianosa Island (National Park Tuscany Archipelago) has proven to be sustainable: captive-bred individuals, morphologically assigned to the taxon A. rufa, were released to the island approximately 20 years ago, establishing an apparently well-adapted population. We have investigated this population by means of 10 microsatellite loci in order to shed light on its genetic structure. Considering that A. rufa is known to crossbreed with A. chukar, the Pianosa Island population was compared at the molecular level with a red-legged partridge breeding stock (Aulla, MS) as well as with a population of pure A. chukar. Our results indicate that the red-legged partridge population from Pianosa, morphologically identified as A. rufa, is actually partly introgressed with A. chukar, questioning its genetic purity and the possible use of this population as a starting stock for future reintroductions elsewhere.

Analysis of the genetic structure of red-legged partridge ( Alectoris rufa, Galliformes) populations by means of mitochondrial DNA and RAPD markers: a study from central Italy

The strong hunting pressure on the red-legged partridge, Alectoris rufa, warranted its inclusion into the list of species of European conservation concern. During the last decades, restocking plans with farmed specimens have counterbalanced the hunting drawings from wild populations. Our concern was the study of A. rufa in the easternmost part of its range, the central Italy, to gain insights into the effects of this compensation practice on the genetic structure of its populations. Partridges from both a geographically isolated, long-time protected, wild population (Pianosa island, Tuscan Archipelago National Park) and two Tuscan farms (Bieri and Scarlino) were investigated. All the specimens were very similar in outward appearance, looking much like to A. rufa. Ninety-six sequences of both Cytochrome b and D-loop Control Region of mitochondrial DNA (mtDNA) were analysed to get evidence of ancestry at the population level, whereas, the Random Amplified Polymorphic DNA (RAPD) technique was employed to get fingerprinting at the individual level. Pianosa and Bieri populations showed both the A. rufa and Alectoris chukar mtDNA lineages, whereas the Scarlino one only the A. rufa-mtDNA line. However, a spread overall pattern of A. rufa × A. chukar hybridisation among specimens, whatever their mtDNA lineage could result to be, was disclosed by means of RAPD species-specific markers. This is the first genetically documented record of the A. rufa × A. chukar hybrids. The occurrence of the pure, native A. rufa genome in the easternmost part of the species’ geographical range may be guessed to be virtual.

A COMPARISON OF THE HELMINTH FAUNAS OF WILD AND FARM-REARED RED-LEGGED PARTRIDGE

More than 4 million farm-reared red-legged partridge (Alectoris rufa; hereafter partridge) are released each year in autumn for harvest purposes in Spain. We compared the helminth fauna of 122 juvenile, farm-reared partridge from 9 farms around Spain with that of 174 wild partridge from 7 harvest areas where no releases currently are conducted. We examined the digestive tract, liver, and trachea. Fourteen helminth species were retrieved (6 from farm-reared partridge, 9 from wild partridge). No trematode or nematode species were shared by both groups of partridge, and only 1 cestode species was present in both populations. Monoxenous nematodes were the most prevalent species found in farm-reared birds. Ascaridia compar, a parasite of the rock partridge (A. graeca) previously unreported in the red-legged partridge, was found in 4 facilities. Heteroxenous helminths, such as Dicrocoelium sp., Raillietina tetragona, and Cheilospirura gruveli, predominated in wild partridge. The prevalence and intensity of helminths in some farmed partridge were higher than expected considering the routine use of antihelminthics in these facilities. Thus, released partridge may introduce new parasites into wild populations, come into contact with parasites of wild partridge, and be negatively affected by their parasite burdens after release. These risks require further study.

Spatial variation in helminth community structure in the red-legged partridge (Alectoris rufa L.): effects of definitive host density.

Parasite community ecology has recently focused on understanding the forces structuring these communities. There are few surveys, however, designed to study the spatial repeatability and predictability of parasite communities at the local scale in one host. The purpose of our study was to address the relationship between infracommunity and component community richness, and to describe spatial variations on the local scale, of helminth parasite communities in an avian host, the red-legged partridge (Alectoris rufta). We sampled 235 wild partridges from 8 separate localities, with different partridge population densities, in the Ciudad Real and Toledo provinces of central Spain, and we determined their overall and intestinal helminth species. We found that habitat variables (mean temperature and land use) were not significantly associated with any component community. The partridge population abundance index was directly correlated with the prevalence and mean intensity of infection but not with component community species richness. There was a curvilinear relationship between infracommunity and component community species richness, as well as negative interspecific associations, for the helminth species assemblage parasitizing the intestine. A nestedness/anti-nestedness pattern, considered as part of a continuum, was associated with prevalence, mean intensity and partridge population abundance index, but not with component community richness. Increases in the partridge population abundance index and the prevalence and mean intensity of infection were associated with increases in helminth community nestedness. Although negative interactions between helminth species could not be ruled out as forces structuring helminth communities, our results suggest that parasite community structure in the red-legged partridge was primarily determined by the extrinsic influence of parasite habitat heterogeneity and its amplification of the differing probabilities of colonization of parasite species.

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.

Self-injury and capture myopathy in net-captured juvenile red-legged partridge with necklace radiotags

Adverse effects of radiotransmitters and handling are major concerns during radiotracking studies, especially in avian species. Fourteen out of 46 (30.4%) juvenile red-legged partridge (Alectoris rufa) trapped using hand-held nets and marked with necklace radiotags during a study in southern Spain died within a few hours after capture. We studied the affected birds and compared data from postmortem examination, blood chemistry, biometry, and meteorology on capture days to identify risk factors related to the deaths. The affected partridge had high creatine kinase plasma levels. Postmortem examination confirmed that the deaths had been due to self-injury, capture myopathy (CM), or both. Distribution of lesions indicated that struggling with the transmitter could have exacerbated CM caused by trapping and handling. There was no effect due to bird size or weight, but deaths were related to capture days with lower mean temperatures and higher humidity. The consideration of combined risk factors such as climate, capture method, and radiotag type may deserve more attention regarding capture and radiotagging techniques, especially in juvenile partridge.

Outbreak of trichomoniasis in a woodpigeon (Columba palumbus) wintering roost

Large numbers of woodpigeons (Columba palumbus) winter each year in southwestern Spain and Portugal, where they feed on acorns. Although mortality in these wintering roosts is generally low, in winter and spring 2001 approximately 2,600 woodpigeons died from trichomoniasis. Diagnosis of the disease was based on postmortem examination, culture and identification of the parasite, Trichomonas gallinae, by PCR. Other viral, bacterial or fungal pathogens were ruled out as cause for the die-off. The gathering of the woodpigeons at game bird feeders set up for red-legged partridges may have contributed to the outbreak. Mortality ceased after treatment with dimetridazole via the game bird feeders. Supplementary feeding of game birds constitutes a risk factor for the appearance of disease outbreaks. Close monitoring of infectious diseases in these populations is important, but treatment of free-living birds should be avoided in favour of other measures, as it poses risks.

Serologic response of red-legged partridges ( Alectoris rufa) after oral inoculation with Toxoplasma gondii oocysts

Thirty 5-month-old red-legged partridges ( Alectoris rufa) reared in battery were divided into five groups: 4 birds in group A, 14 birds in group B, 4 birds in group C, 4 birds in group D and 4 birds in group E, and were inoculated orally with 10, 50, 10 2, 10 3 and 10 4 oocysts of the OV-51/95 strain of Toxoplasma gondii, respectively. During the experiment, blood samples from all birds were drawn every 3–7 days and at necropsy. Serologic response was measured by the modified agglutination test (MAT) and the latex agglutination test (LAT). One bird from each group was killed at 44, 58, 65 and 72 days after inoculation (DAI). From 72 DAI to the end of the experiment, surviving partridges from group B were killed at weekly intervals. The last partridges were sacrified 100 DAI. MAT was the most sensitive and specific test for detecting T. gondii antibodies in the birds. First positive titers were detected by MAT in all sera on 7 DAI, but titers by LAT did not appear until 13 DAI. Antibody titers detected by MAT on 7 DAI were higher in the partridges with the largest inocula (10 3 or 10 4 oocysts) than those inoculated with 10, 50 or 10 2 oocysts. All surviving birds developed a serologic response to T. gondii, with maximum titers of 512–32 768 in the MAT on 13–17 DAI, and positive titers persisted at least until 100 DAI. To the contrary, LAT reveals only very low antibody titers even in partridges inoculated with the highest dose of T. gondii.

Mycobacterium avium disease in wild red-legged partridges (Alectoris rufa)

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.

Dynamics of a reintroduced population of red‐legged partridges Alectoris rufa in central Italy

In order to evaluate the success of a population of red‐legged partridges Alectoris rufa reintroduced into a 33.7 km2 study area, we estimated 15 demographic parameters from 1996 to 1999 by regularly monitoring the population through winter, spring and summer mapping censuses. During the study period, late winter population and spring dispersal decreased, pair number, brood number, brood production rate, chick survival and over winter losses were stable, whereas average brood size, juvenile number, age ratio, adult spring to summer survival, late summer population, and population growth rate from spring to late summer all increased. The population showed a moderate improvement in the overall productivity, mainly related to increased production of young and to a decrease in adult mortality. The improvement in breeding performance took place, in particular, after the second year of study with the conclusion of the releasing session of reared birds.

Descriptive study of an avian pox outbreak in wild red-legged partridges (Alectoris rufa) in Spain.

This study describes the dynamics and epidemiology of an outbreak of avian pox in free-living, red-legged partridges (Alectoris rufa) in southern Spain. Between March 2000 and January 2001, 115 free-living, red-legged partridges (70 juveniles, 45 adults) were captured and radio-tagged. This, together with the necropsy of 44 carcasses (10 juveniles, 34 adults) found in the study area, and the inspection of 108 shot birds (74 juveniles, 34 adults) after a hunting drive in October, permitted a close monitoring of the course of the disease. Forty-one per cent of radio-tagged juveniles but none of 45 radio-tagged adults showed pox-like lesions at the time of capture, recapture, or necropsy. At least 40% of the juveniles that survived into the hunting season, but only 2.9% of the adults inspected at the same time, showed lesions suggestive of infection with avian poxvirus. The survival of juveniles during the peak of the outbreak was much lower than that of the adults, but we found no significant differences between the survival probabilities of juvenile partridges with and without pox-like lesions. Nevertheless, some birds may have developed lesions after their capture. The occurrence and course of the disease in a managed area with intense predator control underlines the need for studies on the combined influence of diseases and predators on population dynamics. Also the need for early detection of diseases for the management of game species is emphasized.

Does supplementary feeding affect organ and gut size of wild red‐legged partridges Alectoris rufa?

Supplementary feeding of wild red‐legged partridges Alectoris rufa with wheat is a widespread management practice in hunting areas in Spain. Many studies note that energetic diets affect the physiology of hand‐reared galliforms. In order to assess if cereal supply might also affect wild birds, we studied the weight of the heart, spleen and liver, and the length of the small intestine and caecum of 129 wild red‐legged partridges from three hunting estates where wheat is supplied, and compared it with 67 partridges from two non‐supplied estates. Non‐supplied partridges had heavier hearts (9%, both in juveniles and adults), and longer caeca (20% in juveniles and 14% in adults) than supplemented birds. An excessive intake of energy‐rich items, such as the wheat supplied, instead of fibre‐rich or proteic natural food, might explain the differences found. The management implications of these findings are discussed.

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.

Food habits of the wildcat (Felis silvestris) in a peculiar habitat: the Mediterranean high mountain

The feeding spectrum of the wildcat Felis silvestris Schreber, 1777 was studied in two sites with different ecological characteristics, both situated in the same Mediterranean environment in the high mountain of the Sierra Nevada National Park, south‐east Spain, where the rabbit Oryctolagus cuniculus is absent. Scat analysis (n=101 faeces; n=402 prey items) showed that the diet is based on rodents, fundamentally wood mouse Apodemus sylvaticus, Mediterranean pine vole Microtus duodecimcostatus and south‐western water vole Arvicola sapidus. Results showed strong differences between the two sites (χ2=74.04, d.f.=5, P<0.001), that is a predominance of voles in the mesic Chico river, whereas mice are predominant in the xeric Tejos ravine. Red‐legged partridge Alectoris rufa and carrion also played an important role, especially in biomass terms. The overall diet differed essentially from that of the Mediterranean region, which surrounds the study area, since in these areas rabbits constitute the primary prey. However, the diet of the mountain wildcats is similar to that in the Eurosiberian floral region, despite its distance from the Sierra Nevada. In conclusion, the Iberian wildcat seems to behave as a facultative specialist, since it prefers rabbits whenever they are available, but rodents constitute most of its diet if rabbits are scarce or absent.

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.

First occurrence of Mesocestoides sp. in a bird, the red-legged partridge, Alectoris rufa, in Spain

Larvae of Mesocestoides sp. were found in the celomic cavity of one red-legged partridge (Alectoris rufa) from Azuara (Aragón, north-eastern Spain). This is the first report of this larval cestode occurring in birds from Spain. None of the other 36 partridges from this area nor 150 partridges from other Spanish localities were affected. The red-legged partridge does not seem to be an important link in the Mesocestoides sp. life-cycle.

Chromosome homology between chicken (Gallus gallus domesticus) and the red-legged partridge (Alectoris rufa); evidence of the occurrence of a neocentromere during evolution

Chromosome-specific paints from macrochromosomes 1–9 and Z of the chicken were hybridised to metaphases of the red-legged partridge and revealed no inter-chromosomal rearrangements. The results from chromosome painting are similar to previous studies on the Japanese quail but different from findings in guinea fowl and several species of pheasant. The difference in centromere position in chicken and partridge chromosome 4, previously assumed to be the result of an inversion, was confirmed. However, FISH mapping of BAC clones from chicken chromosome 4 revealed that the order of loci was the same in both species, indicating the occurrence of a neocentromere during divergence.

The estimation of density dependence using census data from several sites.

The discussion of density dependence in the ecological literature has tended to concentrate on significance testing, whereas estimation is often of more importance. In this paper we use simulation to investigate the bias and precision of a number of methods for estimating density dependence using census data from several sites. The estimation methods examined were a modification of an existing maximum likelihood approach, a regression method, and a new approach using restricted (or residual) maximum likelihood (REML). Simulations indicated that the REML method produced the most accurate estimates, with negligible bias for most parameter combinations. A further advantage of the REML method is that it can be easily implemented using standard statistical software. Using a second series of simulations we investigated the relationship between accuracy of estimation and sample size for the REML method. The results indicated that using more than one site gave substantial improvement in accuracy, but that using more than five sites gave little further improvement unless in excess of 10years of data were available for each site. Where a standard error is required for the density dependence estimate we suggest using bootstrapping at the site level. Where this is not possible, a parametric bootstrap or a randomisation test may be used instead. The REML method is demonstrated using bag totals of red-legged partridges Alectoris rufa and grey partridges Perdix perdix for shoots on estates in East Anglia in the United Kingdom. This paper shows that combining information from several sites can give improved estimation of density dependence, particularly if REML estimation is adopted.