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Rafael Villafuerte - One of the best experts on this subject based on the ideXlab platform.
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habitat selection and home range size of red legged Partridges in spain
Agriculture Ecosystems & Environment, 2008Co-Authors: Miguel Delibesmateos, Francisco J Buenestado, Pablo Ferreras, Francisco S Tortosa, Jose Antonio Blancoaguiar, Rafael VillafuerteAbstract:To understand the factors contributing to the spatial behaviour of the red-legged partridge (Alectoris rufa), a radio-tracking study of free living Partridges was carried out in Spain. During 2000-2002, 275 individuals were captured in four areas with different environmental and management characteristics. Sixty-nine adults and 23 juveniles were used to study space use distributions, including home range size, core area size and habitat selection. According to a generalized linear mixed model, 63% of the variability in home range size was explained by three landscape variables: edge index, average patch size and agricultural disturbance. Habitat selection was not influenced by age or sex because parents and juveniles remained together for most of the year, except during mating. The decline of the red-legged partridge in Spain was preceded by agricultural transformations related to land holding concentration and an increase in cultivated surface per property, which increased patch sizes and decreased edge and marginal areas across Spain.
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Comparative survey of the ectoparasite fauna of wild and farm-reared red-legged Partridges (Alectoris rufa), with an ecological study in wild populations
Parasitology Research, 2004Co-Authors: Javier Millán, Christian Gortázar, María Paz Martín-mateo, Rafael VillafuerteAbstract:We compared the ectoparasite fauna of 89 wild red-legged Partridges ( Alectoris rufa ) from four hunting estates and 25 farm-reared Partridges from three farms. We found 62% of the wild but only 20% of the farmed Partridges harboured ectoparasites. On the wild Partridges, one hippoboscid fly species ( Ornithophila metallica , 2%), two tick species ( Ixodes frontalis , 2%; Hyalomma sp., 17%) and eight louse species were found ( Menacanthus lyali , 3%; M. numidae , 3%; Menopon pallens , 21%; Myrsidea picae , 1%; Goniocotes obscurus , 17%; G. simillimus , 1%; Goniodes dispar , 35%; Cuclotogaster obscurior , 28%). Only two louse species ( G. obscurus , 8%; C. obscurior , 20%) were found on farmed Partridges. Lice prevalence, abundance and species richness were higher in wild birds (44%, 17.0, 1.1) than in farmed Partridges (20%, 1.3, 0.3). Lice prevalence and abundance were higher in dead-found (54%, 21.6) than in shot (23%, 2.3) or live-trapped wild Partridges (no lice). Tick prevalence and abundance was higher in live-trapped (100%, 1.14) than in dead-found (13%, 0.5) or shot Partridges (7%, 0.1). In dead-found Partridges, the total louse prevalence and abundance, the number of louse species and the abundance of G. dispar , G. obscurus , C. obscurior and M. pallens were negatively correlated with partridge body condition; and this correlation for G. dispar abundance was more pronounced in juveniles than in adult Partridges. Since juvenile individuals were also more parasitised by C. obscurior and Hyalomma sp., an acquired immunity against arthropods seems to be relevant. Released Partridges are not a source of new ectoparasites, but these birds may come into contact with many arthropod species with which they had no previous contact.
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effects of a fiber rich diet on physiology and survival of farm reared red legged Partridges alectoris rufa
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2003Co-Authors: Javier Millán, Christian Gortázar, Francisco J Buenestado, Francisco S Tortosa, Pablo Rodriguez, Rafael VillafuerteAbstract:b ´´ ´ Abstract The sudden shift from a commercial energy-rich, fiber-poor diet to natural food is assumed as one of the causes of the low success of gamebird restocking. We fed farmed red-legged partridge (Alectoris rufa) chicks with a diet rich in fiber from their first month of life to the time of their release to assess the possible effects on morphometric characteristics and plasma biochemistry and whether those effects enhance survival after release into the wild. At the time of release, treated Partridges showed heavier gizzards and bursas of Fabricius and longer small intestines than control birds fed commercial feed. Treated birds had also smaller pectoral muscles, lighter spleens and lower plasma levels of proteins, glucose, cholesterol and triglycerides. After release and radiotracking in a hunting area, we found no differences in the survival between both groups. Survival at the end of the study (day 39) was 58.3"14.2% for the control group and 24.2"13.8% for the treated group. The fiber-rich diet seems to have important effects on the physiology of the red- legged partridge, not always taken into account in previous studies. 2002 Elsevier Science Inc. All rights reserved.
Ettore Randi - One of the best experts on this subject based on the ideXlab platform.
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Mitochondrial DNA and microsatellite markers evidence a different pattern of hybridization in red-legged partridge (Alectoris rufa) populations from NW Italy
European Journal of Wildlife Research, 2013Co-Authors: Alessandro Negri, Nadia Mucci, Ettore Randi, Irene Pellegrino, Paolo Tizzani, Pier Giuseppe Meneguz, Giorgio MalacarneAbstract: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.
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hybridisation with introduced chukars alectoris chukar threatens the gene pool integrity of native rock a graeca and red legged a rufa partridge populations
Biological Conservation, 2007Co-Authors: Marina Barilani, Ariane Bernardlaurent, Nadia Mucci, Cristiano Tabarroni, Salit Kark, Jose Antonio Perez Garrido, Ettore RandiAbstract:The decline of over-hunted red-legged (Alectoris rufa) and rock (A. graeca) partridge populations has been contrasted with massive releases of captive-reared birds, often hybrids with non-indigenous A. chukar. Released interspecific hybrids raise the risks of introgressive hybridisation, and can contribute to further depress the fitness of native populations. Aiming to assess the extent of hybridisation, we genotyped the mtDNA control-region and eight nuclear microsatellites in 671 red-legged, rock and chukar Partridges and hybrids, identified by phenotypic traits. Results reveal a diffuse occurrence of hybridisation: (1) 39 samples (6.2%) show mtDNA haplotypes discordant with their phenotypes, indicating red-legged and chukar mtDNA introgression in native rock Partridges; (2) admixture analyses of the microsatellite genotypes identified 32 additional rock Partridges (5.1%) hybridised mainly with chukars. We analysed also 39 samples collected from a presumed natural red-legged x rock partridge hybrid zone in the French Alps. Surprisingly, 28% birds showed typical chukar mtDNAs, indicating hybridisation with introduced chukars or hybrids. This hybrid zone led to an introgression cline of chukar alleles into neighbouring Alpine rock Partridges detectable up to 100 km, which was shorter than expected by neutral genetic theory, and that suggested natural selection against hybrids. These findings indicate that introgressive hybridisation may disrupt local adaptations in natural red-legged partridge and rock partridge populations, and call for strict control of farming and restocking operations.
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S20-5 Evolutionary and conservation genetics of the rock partridge, Alectoris graeca
2006Co-Authors: Ettore RandiAbstract:Rock partridge (Alectoris graeca) populations are declining throughout their range due to habitat changes and overhunting. Massive restocking with captive-reared hybrid birds may lead to risk of genetic pollution. We sequenced 450 nucleotides from the mitochondrial DNA control-region, and genotyped eight microsatellite loci with the aim of investigating phylogeography and population genetic structure in five geographic regions. Both mtDNA and microsatellites indicate that rock partridge populations are significantly differentiated (mtDNA φ ST = 0.86, microsatellite F ST = 0.35, P < 0.001). The mtDNA haplotypes cluster in two phylogroups (bootstrap values ≥ 93%), splitting Partridges from Sicily from all the other sampled populations. Divergence times suggest that rock Partridges have been isolated in Sicily for more than 200 000 years. This deep genetic subdivision is confirmed by multivariate analyses, Bayesian clustering and population assignment tests of microsatellite genotypes. Genetic data indicate differentiation between Partridges in the Alps and populations in the Apennines, Albania and Greece, enabling delimitation of distinct conservation units. Rock Partridges in Sicily (Alectoris graeca whitakeri) meet the criteria of an evolutionary significant unit, and should be managed accordingly.
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Phylogeography of the rock partridge (Alectoris graeca).
Molecular Ecology, 2003Co-Authors: Ettore Randi, Cristiano Tabarroni, S. Rimondi, Vittorio Lucchini, Athanassios I. SfougarisAbstract:We used mitochondrial DNA control-region and microsatellite data to infer the evolutionary history and past demographic changes in 332 rock Partridges (Alectoris graeca) sampled from throughout the species' distribution range, with the exception of the central Balkans region. Maternal and biparental DNA markers indicated concordantly that rock partridge populations are structured geographically (mtDNA phiST = 0.86, microsatellite FST = 0.35; RST = 0.31; P < 0.001). Phylogenetic analyses of 22 mtDNA haplotypes identified two major phylogroups (supported by bootstrap values = 93%), splitting Partridges from Sicily vs. all the other sampled populations at an average Tamura-Nei genetic distance of 0.035, which corresponds to 65% of the average distance between closely related species of Alectoris. Coalescent estimates of divergence times suggested that rock Partridges in Sicily were isolated for more than 200000 years. This deep subdivision was confirmed by multivariate, Bayesian clustering and population assignment analyses of microsatellite genotypes, which supported also a subdivision of Partridges from the Alps vs. populations in the Apennines, Albania and Greece. Partridges in the Apennines and Albania-Greece were probably connected by gene flow since recently through a late Pleistocene Adriatic landbridge. Deglaciated Alps were probably colonized by distinct and, perhaps, not yet sampled source populations. Bottleneck and mismatch analyses indicate that rock Partridges have lost variability through past population declines, and did not expand recently. Deglaciated areas could have been recolonized without any strong demographic expansion. Genetic data partially supported subspecies subdivisions, and allowed delimiting distinct conservation units. Rock Partridges in Sicily, formally recognized as A. g. whitakeri, met the criteria for a distinct evolutionary significant unit.
Francis Buner - One of the best experts on this subject based on the ideXlab platform.
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habitat preferences and survival in wildlife reintroductions an ecological trap in reintroduced grey Partridges
Journal of Applied Ecology, 2010Co-Authors: Elina M Rantanen, Francis Buner, Philip Riordan, Nick Sotherton, David W MacdonaldAbstract:Summary 1. Wildlife reintroductions can help to restore populations and save species from extinction. However, success rates of reintroductions are low due to inherent problems, such as behavioural deficiencies resulting in high post-release predation rates among captive-bred animals. In particular, the released animals may use habitats maladaptively, leading to an ecological trap, i.e. preference for low-quality habitats leading to reduced survival and/or breeding success. Ecological traps in reintroductions can be identified only through intensive studies of habitat preferences and survival of known individuals, but such studies are lacking. 2. We investigated habitat preferences and their relationship with survival by radio-tracking reintroduced, captive-bred grey Partridges Perdix perdix, a widely reintroduced commercial game species and native farmland bird of conservation concern in the UK. The low success rate of grey partridge releases could be due to maladaptive habitat use and a possible ecological trap. 3. Grey Partridges released as pairs in spring showed preferences for crop and field margin habitat. The use of crops had a positive, and use of field margins a negative, association with survival, suggesting field margins could serve as ecological traps for released grey Partridges. Predation rates were high, and field margins probably hosted concentrated predator activity. 4. Grey Partridges released as family groups (coveys) in autumn exhibited a preference for game covers, i.e. areas of tall vegetation specifically planted to provide cover for game birds, and mortality rates were lower than in spring. Habitat use did not affect survival in autumn. 5. Synthesis and applications. We have shown that newly released grey partridge pairs behave maladaptively by preferring a habitat which has a negative association with survival. In grey partridge reintroductions, we recommend releasing grey partridge family groups in autumn rather than releasing pairs of birds in spring, and providing game covers that could induce the groups to settle onto the release areas. In reintroductions in general, the habitat preferences of the released animals should be documented together with their fates, to enable detection of possible ecological traps that could threaten the success of these conservation efforts.
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vigilance time budgets and predation risk in reintroduced captive bred grey Partridges perdix perdix
Applied Animal Behaviour Science, 2010Co-Authors: Elina M Rantanen, Francis Buner, Philip Riordan, Nick Sotherton, David W MacdonaldAbstract:Anti-predator behaviour has direct fitness consequences for prey species and thereby affects their reintroduction success, which has generally been poor. Development of anti- predator behaviour may be impaired in captive conditions which favour low emotional reactivity, resulting in poor perception of danger. Therefore, the newly reintroduced, naive animals may not behave adaptively in terms of anti-predator vigilance, resulting in increased vulnerability to predators. Such behavioural deficiencies may have contributed to the low success rates of reintroductions, but few studies have measured post-release vigilance in captive-bred animals, and none has been published on reintroduced grey Partridges. Therefore, in this study we investigated post-release vigilance behaviour and time budgets in coveys of captive-bred grey Partridges (Perdix perdix; N = 26) released in autumn over two years. We observed the captive-bred grey partridge coveys in the field, and recorded their group vigilance rates as well as time budgets of individual behaviour, including vigilance and feeding. Released grey Partridges had low group vigilance rates and showed poor individual vigilance (4-5% of time spent vigilant) compared to their wild counterparts (43% of time spent vigilant; Watson et al., 2007). Moreover, released individ- uals spent 30-48% of their time feeding, and fed at this rate throughout the day, instead of concentrating their feeding around dawn and dusk like wild grey Partridges do. The revealed vigilance and feeding behaviour in released grey Partridges are likely to increase vulnerability to predators, and therefore offer plausible explanations for the high preda- tion rates of released grey Partridges observed with these and previous releases. Rearing methods should be developed to encourage wariness in the captive animals. In addition, the adaptive bimodal feeding routine of wild grey Partridges should be encouraged in the captive-bred birds, for example by feeding them only at dawn and dusk. © 2010 Elsevier B.V. All rights reserved.
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ecologically enhanced areas a key habitat structure for re introduced grey Partridges perdix perdix
Biological Conservation, 2005Co-Authors: Francis Buner, Markus Jenny, Niklaus Zbinden, Beat NaefdaenzerAbstract:Abstract We analysed the spatial distribution of home-ranges and the habitat use of re-introduced grey Partridges Perdix perdix in relation to newly established ecologically enhanced areas, i.e. wild-flower strips and hedges, within an intensively cultivated area in Switzerland from which the species had become extinct. All birds settled within the ca. 30% of the study area where the proportion of enhanced areas was highest (5.8%). At the level of the individual family group, we found a significant over-proportional use of enhanced areas throughout the year. Furthermore, when the birds used the agricultural fields, the use densities strongly declined with distance from the nearest enhanced area. Thus, the availability and spatial distribution of ecologically enhanced areas were the main determinants of the Partridges’ range use. These results indicate that a framework of ecologically enhanced areas is a key habitat structure for grey Partridges, and that these enhancements, even if small in proportion, were the crucial first measure to restore the research area to an appropriate grey partridge habitat and, thus, the basis for successful re-introduction in this intensively cultivated area.
Nicholas J. Aebischer - One of the best experts on this subject based on the ideXlab platform.
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Grey Partridge Perdix perdix in the UK: recovery status, set-aside and shooting
Ibis, 2010Co-Authors: Nicholas J. Aebischer, Julie A. EwaldAbstract:The Grey Partridge Perdix perdix is a European Species of Conservation Concern and a priority species under the UK Biodiversity Action Plan. The Game & Wildlife Conservation Trust (GWCT) launched a major programme to help partridge recovery in the UK, built on the GWCT's Partridge Count Scheme (PCS) and including a demonstration site from 2002. We contrast the national picture of no population change since 1999 from BTO monitoring with a doubling of spring pair density on PCS sites. At the demonstration site, where set-aside was used for habitat creation, Grey Partridge breeding density increased six-fold, to 18 pairs/km 2 , then fell back. The drop coincided with bad weather but also with the disappearance of rotational set-aside when the set-aside rate fell to zero, which halved the amount of brood-rearing habitat. Non-rotational set-aside remained unchanged, as did the amount of nesting habitat that it provided. Grey Partridge density was significantly linked to rotational set-aside, especially wild bird cover, but not to non-rotational set-aside. The demonstration project also showed that, with appropriate precautions, it was possible to shoot over 60% of Red-legged Partridges Alectoris rufa while maintaining Grey Partridge losses below 5%. On PCS sites, the annual change in spring density in recent years differed in relation to neither shooting pressure nor intensity of Red-legged Partridge releasing. Provision of brood-rearing habitats and game cover increased with the latter, and probably counteracts the shooting losses of Grey Partridges on Red-legged Partridge shoots when, as on PCS sites, active measures keep those losses below 20%. Targeted personal advice channelled through the PCS has been fundamental to these successes and must be expanded.
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the effect of agri environment schemes on grey Partridges at the farm level in england
Agriculture Ecosystems & Environment, 2010Co-Authors: J A Ewald, Nicholas J. Aebischer, Suzanne M Richardson, Philip V Grice, Andrew I CookeAbstract:Abstract In this study results from land managed by volunteer members of the Game and Wildlife Conservation Trust's Partridge Count Scheme (PCS) were used to determine how well Environmental Stewardship (ES) and its predecessor schemes have performed for one intensively studied farmland bird, the grey partridge (Perdix perdix) between 2005 and 2008. The individual agri-environmental scheme (AES) options that PCS members chose to implement were classified into groups based on the habitat that they provide for grey Partridges at different stages of their life cycle. Three groups of options had consistently positive effects—beetle banks, conservation headlands and wild bird cover, all in-field options. Options with consistently negative effects were those including grass and scrub management. Unfortunately for grey Partridges, beetle banks and conservation headlands currently have very little uptake within AES; of non-PCS agreements 1.9% include beetle banks and 2% conservation headlands. Non-PCS agreements have a slightly higher uptake of wild bird cover (12.9%).
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The GWCT Grey Partridge Recovery Programme: a Species Action Plan in Action
2009Co-Authors: Nicholas J. AebischerAbstract:In 1994, the UK government launched its Biodiversity Action Plan (BAP). Its list of BAP species included the grey partridge Perdix perdix, whose UK numbers had declined by 91% since 1962. The government set numerical targets in its grey partridge Species Action Plan, then nominated the Game & Wildlife Conservation Trust (GWCT) as lead partner to take the Plan forward. To this end, the GWCT has sought to raise awareness of the issues among the farming and shooting communities with promotional material. It has encouraged land and shoot managers to join its Partridge Count Scheme and established local Partridge Groups as a focus for information dissemination, guiding management with local targets set using landscape characteristics to estimate the potential distribution of grey Partridges at the 1-km level. Leading by example, the GWCT has demonstrated on the ground how appropriate management leads to successful grey partridge recovery, and it has initiated research into optimal methods of re-establishing grey Partridges in areas of extinction. I consider the current population status of the grey partridge in the UK, review the targets of the Species Action Plan in the light of that status, and discuss the chances of success.
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vigilance and fitness in grey Partridges perdix perdix the effects of group size and foraging vigilance trade offs on predation mortality
Journal of Animal Ecology, 2007Co-Authors: Mark Watson, Nicholas J. Aebischer, Will CresswellAbstract:Summary 1 Vigilance increases fitness by improving predator detection but at the expense of increasing starvation risk. We related variation in vigilance among 122 radio-tagged overwintering grey Partridges Perdix perdix (L.) across 20 independent farmland sites in England to predation risk (sparrowhawk Accipiter nisus L., kill rate), use of alternative antipredation behaviours (grouping and use of cover) and survival. 2 Vigilance was significantly higher when individuals fed in smaller groups and in taller vegetation. In the covey period (in early winter when Partridges are in flocks), vigilance and use of taller vegetation was significantly higher at sites with higher sparrowhawk predation risk, but tall vegetation was used less by larger groups. Individuals were constrained in reducing individual vigilance by group size and habitat choice because maximum group size was determined by overall density in the area during the covey period and by the formation of pairs at the end of the winter (pair period), when there was also a significant twofold increase in the use of tall cover. 3 Over the whole winter individual survival was higher in larger groups and was lower in the pair period. However, when controlling for group size, mean survival decreased as vigilance increased in the covey period. This result, along with vigilance being higher at sites with increasing with raptor risk, suggests individual vigilance increases arose to reduce short-term predation risk from raptors but led to long-term fitness decreases probably because high individual vigilance increased starvation risk or indicated longer exposure to predation. The effect of raptors on survival was less when there were large groups in open habitats, where individual Partridges can probably both detect predators and feed efficiently. 4 Our study suggests that increasing partridge density and modifying habitat to remove the need for high individual vigilance may decrease partridge mortality. It demonstrates the general principle that antipredation behaviours may reduce fitness long-term via their effects on the starvation–predation risk trade-off, even though they decrease predation risk short-term, and that it may be ecological constraints, such as poor habitat (that lead to an antipredation behaviour compromising foraging), that cause mortality, rather than the proximate effect of an antipredation behaviour such as vigilance.
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The relative effects of raptor predation and shooting on overwinter mortality of grey Partridges in the United Kingdom
Journal of Applied Ecology, 2007Co-Authors: M Watson, Nicholas J. Aebischer, G. R. Potts, Julie A. EwaldAbstract:1. Factual information is key to resolving conflicts between raptor conservation and gamebird management, especially when the conservation status of one of the species involved is threatened. The grey partridge Perdix perdix is a UK Biodiversity Action Plan species because of a marked decline in abundance caused by agricultural intensification. Recently, the number of raptors present on farmland and the commercial shooting of red-legged Partridges Alectoris rufa have both increased. To inform conservation action, the relative impacts of these two factors on grey partridge populations urgently require quantification. 2. On our study site areas of low density of grey Partridges coincided with areas of high raptor density. However, these areas were managed intensively for shooting and for two areas that suffered local partridge extinction, the 3-year average percentage of Partridges shot exceeded 50%. 3. Grey partridge mortality to raptors between autumn and spring lay between 9·5% of autumn density (assumes losses to raptors occurred before shooting) and 15% of post-shooting density (if all losses to raptors were post-shooting). A deterministic model suggested that this rate of loss would reduce the equilibrium density of spring pairs by 11-26% relative to a situation without raptors. In comparison, shooting losses across the study area amounted to 35-39% of autumn density, more than double the losses to raptor predation, with a predicted reduction of 68-85% in equilibrium density of spring pairs. 4. Synthesis and applications. Shooting based on large-scale releases of red-legged Partridges acts in a density-independent manner and can lead to local grey partridge extinction. Removing the grey partridge from the UK quarry list would be counterproductive, as most action to boost wild grey partridge densities is carried out by enthusiasts with shooting as the incentive. However, it is imperative that managers of intensive shoots based on gamebird release adopt measures to reduce shooting pressure on wild grey Partridges at low density. These include training shooters to distinguish between grey and red-legged Partridges and implementing a warning system (whistle) to alert the gun line when birds of the non-target species are approaching. Such voluntary measures are effective in addressing overshooting, which has greater implications for grey partridge conservation than raptor predation.
David W Macdonald - One of the best experts on this subject based on the ideXlab platform.
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habitat preferences and survival in wildlife reintroductions an ecological trap in reintroduced grey Partridges
Journal of Applied Ecology, 2010Co-Authors: Elina M Rantanen, Francis Buner, Philip Riordan, Nick Sotherton, David W MacdonaldAbstract:Summary 1. Wildlife reintroductions can help to restore populations and save species from extinction. However, success rates of reintroductions are low due to inherent problems, such as behavioural deficiencies resulting in high post-release predation rates among captive-bred animals. In particular, the released animals may use habitats maladaptively, leading to an ecological trap, i.e. preference for low-quality habitats leading to reduced survival and/or breeding success. Ecological traps in reintroductions can be identified only through intensive studies of habitat preferences and survival of known individuals, but such studies are lacking. 2. We investigated habitat preferences and their relationship with survival by radio-tracking reintroduced, captive-bred grey Partridges Perdix perdix, a widely reintroduced commercial game species and native farmland bird of conservation concern in the UK. The low success rate of grey partridge releases could be due to maladaptive habitat use and a possible ecological trap. 3. Grey Partridges released as pairs in spring showed preferences for crop and field margin habitat. The use of crops had a positive, and use of field margins a negative, association with survival, suggesting field margins could serve as ecological traps for released grey Partridges. Predation rates were high, and field margins probably hosted concentrated predator activity. 4. Grey Partridges released as family groups (coveys) in autumn exhibited a preference for game covers, i.e. areas of tall vegetation specifically planted to provide cover for game birds, and mortality rates were lower than in spring. Habitat use did not affect survival in autumn. 5. Synthesis and applications. We have shown that newly released grey partridge pairs behave maladaptively by preferring a habitat which has a negative association with survival. In grey partridge reintroductions, we recommend releasing grey partridge family groups in autumn rather than releasing pairs of birds in spring, and providing game covers that could induce the groups to settle onto the release areas. In reintroductions in general, the habitat preferences of the released animals should be documented together with their fates, to enable detection of possible ecological traps that could threaten the success of these conservation efforts.
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vigilance time budgets and predation risk in reintroduced captive bred grey Partridges perdix perdix
Applied Animal Behaviour Science, 2010Co-Authors: Elina M Rantanen, Francis Buner, Philip Riordan, Nick Sotherton, David W MacdonaldAbstract:Anti-predator behaviour has direct fitness consequences for prey species and thereby affects their reintroduction success, which has generally been poor. Development of anti- predator behaviour may be impaired in captive conditions which favour low emotional reactivity, resulting in poor perception of danger. Therefore, the newly reintroduced, naive animals may not behave adaptively in terms of anti-predator vigilance, resulting in increased vulnerability to predators. Such behavioural deficiencies may have contributed to the low success rates of reintroductions, but few studies have measured post-release vigilance in captive-bred animals, and none has been published on reintroduced grey Partridges. Therefore, in this study we investigated post-release vigilance behaviour and time budgets in coveys of captive-bred grey Partridges (Perdix perdix; N = 26) released in autumn over two years. We observed the captive-bred grey partridge coveys in the field, and recorded their group vigilance rates as well as time budgets of individual behaviour, including vigilance and feeding. Released grey Partridges had low group vigilance rates and showed poor individual vigilance (4-5% of time spent vigilant) compared to their wild counterparts (43% of time spent vigilant; Watson et al., 2007). Moreover, released individ- uals spent 30-48% of their time feeding, and fed at this rate throughout the day, instead of concentrating their feeding around dawn and dusk like wild grey Partridges do. The revealed vigilance and feeding behaviour in released grey Partridges are likely to increase vulnerability to predators, and therefore offer plausible explanations for the high preda- tion rates of released grey Partridges observed with these and previous releases. Rearing methods should be developed to encourage wariness in the captive animals. In addition, the adaptive bimodal feeding routine of wild grey Partridges should be encouraged in the captive-bred birds, for example by feeding them only at dawn and dusk. © 2010 Elsevier B.V. All rights reserved.