Effect of Sub-Polar Gyre, North Atlantic Oscillation and ambient temperature on size and abundance in the Icelandic Arctic fox

Animals are exposed to environmental factors that influence their life history and body size. Here we used the Arctic fox ( Vulpes lagopus ) as an indicator of the complex links between largescale environmental variables that influence both marine and tundra trophic dynamics to demonstrate how they affect the fox's body size and abundance. The Arctic fox inhabits throughout Iceland, where it preys mainly on birds. We studied the effects of the Sub-Polar Gyre (SPG), winter and summer North Atlantic Oscillation (NAO), mean annual winter and summer temperature, and geographic sector (eastern and western Iceland, which differ in their ecology) on variations in mandible size (6345 specimens) and body mass (2732 specimens) as well as abundance on the Arctic fox in Iceland. We found that (a) SPG index negatively affected male mandible length as well as body mass of both sexes. SPG was also negatively related to fox abundance. (b) Summer NAO had a negative effect on Arctic foxes, that is, cold summers were correlated with shorter mandibles and lower body mass. (c) Winter NAO had a significant negative effect (although weaker than that of summer NAO) on female mandible length, but not on body mass. (d) Summer temperature had a positive effect on female mandible length, but no effect on body mass. However, winter temperature had no effect on either the mandible or body mass. (e) Foxes in the eastern sector had shorter mandibles and were of lighter mass than those in the western sector. We suggest that climate conditions during the growth period of the young affected their final size both directly, by influencing energy metabolism for maintenance, but mainly through their effects on food availability. As far as we are aware, this is the first report that the SPG has an effect on vertebrates, let alone terrestrial ones.     

Evaluation of Cage-Traps and Cable Restraint Devices to Capture Red Foxes in Spain

Abstract: A growing international concern for the welfare of animals, combined with the need to capture and handle specific species for conservation, management, or recreational purposes, is increasing the need for scientific evaluation of capture methods. We evaluated the efficiency, selectivity, and injury of cable restraint devices and cage-traps for capture of red foxes (Vulpes vulpes) in 4 sites of Castilla y León (Spain) during spring of 2006. All traps performed similarly at all sites, with no apparent site and trap interactions. Fox capture rates and mechanical efficiencies of the Belisle® (Edouard Belisle, Saint Veronique, PQ, Canada) and Collarum® (Wildlife Control Supplies, East Granby, CT; mention of product names does not infer endorsement) were similar, but both had higher capture rates than the cage-trap. Similar to previous studies, the Collarum was 100% selective for canids and had a selectivity of 94.4 overall, which was higher than that for the Belisle (63.4); both Collarum and Belisle were much more selective than the cage-trap (21.4). Fox injuries were statistically indistinguishable using injury scores, but the Collarum and the Belisle surpassed international standards for humane trapping; an insufficient number of animals were captured in cage-traps to allow evaluation. Both the Collarum and the Belisle may be useful for the capture of foxes in Spain, but training and experience with each may be necessary to ensure the highest efficiency while preventing injuries, especially to nontarget species. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):830–836; 2008)     

Natal Dispersal and Philopatry of Red Foxes in Urban and Agricultural Areas of Illinois

Abstract: Dispersal and philopatry may be influenced by habitat, intraspecific and interspecific interactions, and resource quality. Dispersal may vary substantially between urban and rural wildlife populations due to differences in urban-rural habitat and trophic relationships. We examined effects of environmental, body condition, and social influences on dispersal and philopatry of urban and rural red foxes (Vulpes vulpes) in east-central Illinois and western Indiana, USA. We recorded 96 dispersal events and 66 cases of philopatry in juvenile foxes. We used Akaike's Information Criterion to evaluate regression models of dispersal probability, initiation date, distance, and days spent dispersing. Habitat (i.e., urban-rural), sex, row-crop percentage in natal home ranges, family home-range overlap, and social interactions with family members all influenced dispersal probability. Juvenile foxes with fewer row crops in their home ranges, individuals with high intra-familial overlap of summer range, females, and urban foxes were associated with philopatry. Dispersals began mid-September and ended in March. Rural juveniles dispersed 23 days earlier than did urban conspecifics. Heavier foxes (capture wt) and those with heavily row-cropped home ranges dispersed earlier. Littermates dispersed at similar times, although in different directions. Dispersal distances averaged 44.8 km for all foxes (range = 1–478 km). Male and urban foxes dispersed farther than female and rural foxes, respectively. Time between dispersal and settlement averaged 41.2 days (range = 2–114 days), with urban foxes dispersing over longer time periods. Dispersal direction between the sexes had different directional distributions, though mean vectors for both were oriented north. Dispersing foxes selected cropland in proportion to availability, whereas grassland was selected preferentially. We demonstrate influences of habitat, resource availability, familial social interactions, and interspecific interactions on dispersal and philopatry of juvenile red foxes in an intensively row-cropped region of the Midwest. Our findings demonstrate red fox dispersal ecology differences in urban and rural environments. In intensively row-cropped regions of the Midwest where landscape crop harvest alters dispersal timing, minimizing seasonal habitat changes with permanent vegetative structure (e.g., crop food plots, native grass fields) would likely delay dispersal activity, and increase survival.     

Population Genetic Analysis of Serbian Red Foxes (Vulpes vulpes) by Means of Mitochondrial Control Region Sequences

A population genetic analysis based on sequences of the mitochondrial control region in 110 red foxes from five sampling localities in northern Serbia was carried out. The analysis yielded nine different haplotypes. Neither haplotype phylogeny nor their distribution was in accordance with the geographic location of the populations. In particular, the data failed to detect an unequivocal influence of the two big rivers, the Danube and the Tisza, separating the populations studied. Population differentiation was altogether low, without any relationship to the rivers as possible migration barriers. Although the possibility of foxes crossing the rivers over bridges or by swimming, thus keeping up gene flow, cannot be ruled out, it is most probable that the control region sequences are not sensitive enough to resolve small-scale population relationships but rather show patterns determined by stochastic processes such as genetic drift or lineage sorting.     

Bait Uptake and Caching by Red Foxes and Nontarget Species in Urban Reserves

Abstract: The management of biodiversity in urban areas provides a challenge for conservation managers who are interested in the recovery of native species by controlling exotic species. Exotic-animal control programs using poisons can be contentious in terms of the health and safety of nontarget species, including people. Managing exotic predators in urban areas must be effective at 2 levels: controlling the target species and minimizing impacts to nontarget species. We investigated the feasibility of instigating a poison-baiting program to control nonindigenous European red foxes (Vulpes vulpes) in city conservation reserves (Perth, Australia). We selected 3 reserves to assess the safety and efficacy of baiting for foxes by maximizing bait uptake by the target species, and minimizing uptake by nontarget species. We tested 2 types of meat bait using 4 bait presentation methods (untethered, uncovered; untethered, covered; tethered, uncovered; tethered, covered). Bait uptake by foxes was highest in urban reserves compared to that in a peri-urban reserve. Bait type and presentation method equally explained bait uptake by foxes. Untethered and uncovered baits were removed 10% more often by foxes, and untethered baits had been cached more often than tethered baits. Baits cached by foxes for up to 1 week were not removed by species other than foxes. Domestic dogs and native birds were common nontarget species to remove baits. Dogs showed no aversion to removing any bait type, nor did bait presentation method influence bait removal. Birds removed fewer baits that had been tethered and covered. We provide an evidence base to demonstrate that bait uptake by nontarget species can be minimized, although we suggest that a fox control program is likely to be more of an organizational challenge to change public attitudes toward responsible dog ownership rather than a technical challenge to poison foxes.     

Nutrient limitation of phytoplankton production in Alaskan Arctic foothill lakes

We used 54 enrichment bioassays to assess nutrient limitation (N, P) of ¹⁴C uptake by natural phytoplankton assemblages in 39 lakes and ponds in the Arctic Foothills region of Alaska. Our purpose was to categorize phytoplankton nutrient status in this under-represented region of North America and to improve our ability to predict the response of primary production to anticipated anthropogenically mediated increases in nutrient loading. Experiments were performed across several watersheds and included assays on terminal lakes and lakes occupying various positions in chains (lakes in series within a watershed and connected by streams). In total, 89% (48 of 54) of the bioassays showed significant stimulation of ¹⁴C primary production by some form of nutrient addition relative to unamended controls. A significant response was observed following enrichment with N and P, N alone and P alone in 83, 35 and 22% of the bioassays, respectively. In experiments where N and P proved stimulatory, the influence of N alone was significantly greater than the influence of P alone. Overall, the data point to a greater importance for N than P in regulating phytoplankton production in this region. The degree of response to N and P enrichment declined as the summer progressed and showed no relationship to irradiance or water temperature, suggesting secondary limitation by some micronutrient such as iron as the summer advanced. Phytoplankton nutrient status was often consistent across lakes within a watershed, suggesting that watershed characteristics influence nutrient availability. Lakes in this region will clearly show increased phytoplankton production in response to anthropogenic activities and anticipated changes in climate that will increase nutrient loading.     

Survival and Cause-Specific Mortality of Red Foxes in Agricultural and Urban Areas of Illinois

Abstract: Range expansion and population increase by coyotes (Canis latrans), reduced hunting and trapping, and intensified agricultural practices in the Midwest have altered red fox (Vulpes vulpes) mortality, although relative impacts of these factors are unknown. We examined mortality causes and survival of red foxes in urban and rural agricultural areas of Illinois, using radio telemetry data from 335 foxes (Nov 1996 to May 2002). We used Akaike's Information Criterion to evaluate six survival models for foxes reflecting 1) environmental effects, 2) intrinsic effects, 3) temporal effects, 4) behavioral effects, 5) social effects, and 6) a global model. Environmental and intrinsic models of survival were optimal for adult foxes. Adult foxes with low (0-20%) and high (80-100%) percentages of row crops in their home ranges had higher survival than adults with moderate percentages (40-70%). Heavier adults at capture also survived better. A global model (all covariates) was optimal for juvenile foxes. Higher juvenile survival associated with larger litters, lower body fat, and reduced dispersal time. Yearly survival ranged from 0.18 for rural male juveniles to 0.44 for rural female adults. Adult survival rates (0.35) were 11% higher than juvenile survival rates (0.24). Yearly survival varied for urban foxes due to cyclic outbreaks of sarcoptic mange (Sarcoptes scabei). Thus, summer survival (May-Sep) of urban juveniles ranged from 0.10 (mange present) to 0.83 (no mange recorded). Mange was the most common (45% of all fatalities) source of mortality for urban foxes, followed by road kill (31%). We recorded only 4 mange fatalities (2%) for rural foxes. Rural foxes experienced low hunting mortality (7%) and equivalent road kill and coyote predation fatalities (40% each). Sources of mortality for midwestern foxes have dramatically changed since the 1970s when hunting was the major cause of mortality. Coyote predation has effectively replaced hunting mortality, and cyclic patterns of mange outbreaks in urban fox populations might indicate a dynamic source or sink relationship to surrounding rural fox populations. Absent mange, urban areas might provide refugia for red foxes where coyote populations persist at high densities in rural areas. Managers of sympatric urban and rural wildlife populations must understand survival dynamics influencing the population at the landscape level.     

蓝狐消化道内分泌细胞的免疫组化研究

蓝狐又名北极狐(Alopex lagopus),属于食肉目(Carnivora),犬科(Canidae),北极狐属(Alopex).     

Age-specific variation in reproduction is largely explained by the timing of territory establishment in the New Zealand stitchbird Notiomystis cincta

1. Using data from 327 nests over a consecutive 8-year period we examined age-specific variation in reproduction in a population of stitchbirds (or hihi) Notiomystis cincta and related how differences in reproductive performance were linked to the timing of territory establishment and breeding. 2. Across the population all reproductive parameters showed a quadratic relationship with an increase mainly between the first and second breeding season and a decline after the fourth year. A longitudinal analysis showed evidence of senescence by the sixth year in the numbers of chicks fledged and recruited. 3. Reproductive increases between years 1 and 2 were the result of poor-quality females dying after their first breeding season (differential selection hypothesis) in combination with surviving females showing improvements in reproduction in their second year (individual improvement/constraint hypothesis). 4. There was no effect of mate experience or territory quality on improvements in breeding between years. 5. The key variable influencing reproductive output was the timing of breeding. Birds that started laying earlier were more likely to lay multiple clutches in any given season. This was the main difference between first-year and older birds; generally first-year birds initiated egg laying later and consequently laid fewer clutches. 6. Approximately half of all first-year birds did not establish their territory until after the breeding season had begun. This delay in territory establishment resulted in these birds delaying breeding, which resulted in them having a lower reproductive output relative to all other birds. First-year birds that managed to establish their territory before breeding commenced, had similar rates of reproduction as older birds. 7. There was a positive relationship between the timing of territory establishment during a female's first year and her hatching date in the previous breeding season. We hypothesize that this was because late-hatched females were less able to effectively compete for territories against earlier-hatched members of their cohort, and this delayed their establishment and breeding in their first year. Thus, this social constraint is likely to be a major factor driving age-specific reproductive variation in this population.     

漠河地区养殖的北极狐冬季被毛性状与保温性能的关系

被毛是哺乳动物最主要的特征之一,其保温功能对动物适应寒冷环境意义重大。为了探讨北极狐(Alopex lagopus)在被毛性状上如何适应寒冷的气候条件,对大兴安岭漠河地区人工养殖北极狐的背中部直针毛、上层绒毛、下层绒毛的长度、毛根细度、毛干细度以及毛密度、单个毛束内的毛数量、毛束密度、复合毛囊最大横切面积、1mm2内复合毛囊最大横切面总面积等14个性状因子进行测量分析。结果表明,北极狐绒毛分为上下两层,下层绒毛的长度、毛根细度和毛干细度均小于上层绒毛,上层绒毛长度与直针毛接近,直针毛长度与上层绒毛、下层绒毛长度均不存在显著相关性;毛密度与毛束密度极度正相关(P0.01),但与毛根细度、毛干细度、单个毛束内的毛数量和1mm2内复合毛囊最大横切面总面积不存在显著相关性,且与复合毛囊最大横切面积的相关性较小;复合毛囊最大横切面积受毛根细度、单个毛束内的毛数量和毛束密度的影响较小。北极狐不是通过降低毛细度的方式来增加毛密度以加强保温功能,而是通过改变被毛在皮肤内的分布格局来增加毛密度,以及将有髓质的绒毛分为上下两层来改变被毛空间结构这两种策略提高被毛内静止空气的量以加强保温功能,进而适应高纬度地区的寒冷环境。     

Feeding wild birds in gardens: A test of water versus food

Bird feeding in residential gardens is an increasingly popular human–wildlife interaction. In Australia, the practice is discouraged by most government and nongovernment wildlife conservation agencies, although advice varies and the most common recommendation is to provide water and habitat for birds rather than supplementary food. This study compares bird abundance and diversity when residents in a Melbourne municipality provide water for birds versus food. Bird abundance was greater when food was provided compared with water, but avian assemblages did not differ.     

Effect of reward level on individual variability in demand feeding activity and growth rate in Arctic charr and rainbow trout

Groups of Arctic charr and rainbow trout were fed by using demand feeders and their individual trigger actuations registered with a PIT-tag (Passive Integrated Transponder) system. Food was supplied at two reward levels, low and high, to five replicate groups of each species for 21 to 27 days. The reward level was defined as the amount of food obtained in response to a single trigger actuation. The effects of reward level on individual demand feeding activity and growth rale were assessed.
As a result of high demand feeding activity, the daily food rations for trout were in excess of their needs at both reward levels. This can be ascribed to the fact that they compensated a low reward level by increasing their bite activity. In contrast, demand feeding activity in charr did not differ significantly between reward levels. Instead, resulting food rations were limiting and excessive, at low and high reward levels, respectively. The variation in bite activity between individuals (measured as their proportional contribution to the total number of trigger actuations within a group) for charr was significantly higher in the low-reward treatment than in the high-reward level. For trout, the variation in bite activity did not differ significantly between treatments. Differences in response to reward level are suggested to be due to the fact that the social hierarchy is weaker in trout than in charr; i.e. the differences in bite activity between dominant and non-dominant individuals are smaller in trout. At both reward levels, the benefit of being dominant, measured in terms of growth rate was significant for charr but non-significant for trout.     

Historical and ecological determinants of genetic structure in arctic canids

Wolves (Canis lupus) and arctic foxes (Alopex lagopus) are the only canid species found throughout the mainland tundra and arctic islands of North America. Contrasting evolutionary histories, and the contemporary ecology of each species, have combined to produce their divergent population genetic characteristics. Arctic foxes are more variable than wolves, and both island and mainland fox populations possess similarly high microsatellite variation. These differences result from larger effective population sizes in arctic foxes, and the fact that, unlike wolves, foxes were not isolated in discrete refugia during the Pleistocene. Despite the large physical distances and distinct ecotypes represented, a single, panmictic population of arctic foxes was found which spans the Svalbard Archipelago and the North American range of the species. This pattern likely reflects both the absence of historical population bottlenecks and current, high levels of gene flow following frequent long-distance foraging movements. In contrast, genetic structure in wolves correlates strongly to transitions in habitat type, and is probably determined by natal habitat-biased dispersal. Nonrandom dispersal may be cued by relative levels of vegetation cover between tundra and forest habitats, but especially by wolf prey specialization on ungulate species of familiar type and behaviour (sedentary or migratory). Results presented here suggest that, through its influence on sea ice, vegetation, prey dynamics and distribution, continued arctic climate change may have effects as dramatic as those of the Pleistocene on the genetic structure of arctic canid species.     

The Effect of Breast‐Feeding with and without Formula Use on the Risk of Obesity at 4 Years of Age

Objective: To determine the minimal duration of breast‐feeding required to protect against later obesity, whether the concurrent use of formula lessened any protective effect of breast‐feeding, and what maternal or child characteristics might modify the association between breast‐feeding and child obesity. Research Methods and Procedures: This was a retrospective cohort study. Participants were 73, 458 white and black low‐income children followed from birth through 4 years of age. Obesity at age 4 years was defined as measured BMI ≥ 95th percentile. Feeding exposure was based on breast‐feeding duration and the age of formula initiation. Covariates were obtained from the children's birth certificates. Results: At age 4 years, the prevalence of obesity was 11.5%. Only 16% of children were breast‐fed 8 weeks or longer. Breast‐feeding was associated with a reduced risk of obesity only in white children whose mothers had not smoked in pregnancy. In this subgroup, the reduction in obesity risk (adjusted odds ratio, 95% confidence interval), compared with those never breast‐fed, occurred only for children who were breast‐fed at least 16 weeks without formula (0.71, 0.56 to 0.92) or at least 26 weeks with concurrent formula (0.70, 0.61 to 0.81). Among whites whose mothers smoked in pregnancy and among blacks, breast‐feeding was not associated with a reduced risk of obesity at age 4 years. Discussion: In a population of low‐income children, breast‐feeding was associated with a reduced risk of obesity at age 4 years only among whites whose mothers did not smoke in pregnancy and only when breast‐feeding continued for at least 16 weeks without formula or at least 26 weeks with formula.     

Comparative Space Use and Habitat Selection of Moose Around Feeding Stations

ABSTRACT The practice of feeding cervids in winter, either as a supplement to enhance nutritional status or to divert animals away from roads, railways, or vulnerable habitats, is rising noticeably. Moose (Alces alces) densities in Scandinavia are currently at historically high levels, resulting in amplified damage to economically important young Scots pine (Pinus sylvestris) forest stands. Nevertheless, there is limited information as to how diversionary feeding affects herbivore space use and habitat selection. We followed 32 female moose marked with Global Positioning System collars to evaluate 1) if feeding stations serve as attraction points to the extent that habitat-selection patterns resemble those of central-place foragers (i.e., high usage and more uniform selection close to the attraction point), and 2) if moose using feeding sites select young pine stands less than those not using feeding sites. Moose that used diversionary forage concentrated their space use around feeding stations and selected habitats as predicted for a central-place forager with a decreasing probability of using areas away from feeding sites and a low degree of habitat selectivity close to feeding sites. However, moose that used feeding sites continued to select young pine stands to the same extent as moose that did not use feeding sites. Feeding sites were, therefore, not successful in diverting moose away from valuable natural browse, so we recommend wildlife managers establish feeding sites in sacrifice areas where moose browsing is permissible and, if possible, >1 km from young pine plantations.     

Genetic variation in populations of the arctic perennial Pedicularis dasyantha (Scrophulariaceae), on Svalbard,Norway

Isozyme variability was examined in 13 geographically isolated populations of the endemic arctic hairy lousewort (Pedicularis dasyantha) in the Svalbard Archipelago, 80° N latitude, Norway. Of the 23 enzyme systems screened on five buffer systems 18 were interpretable. Of the 31 reliable loci, only 6-phosphogluconate dehydrogenase (6-Pgd), was polymorphic. However, no heterozygotes were detected. Frequencies for allele 1 among the populations varied from 1.00 in the north to 0.00 in the south and 0.53 in the central “overlap” region. At the species level the mean number of alleles per locus (A) was 1.03. Percentage of polymorphic loci (P) was 3%. Expected heterozygosity (H_e) was 0.016. At the population level the mean number of alleles per locus was 1.01, and 1.1% of the loci were polymorphic. H_e was 0.004. These values are low compared to endemic, widespread, selling, and outcrossed species. Flower color morphs were distinct. They varied within and among the 13 populations. The frequency of color morphs coincided with allele frequencies of 6-PGD: allele 1 was found in dark purple morphs, and allele 2 was found in light morphs. This species shows more isozyme genetic variability than the five other species reported in the genus but generally less variation than other species with limited regional distributions. Low-level genetic variation in this diploid species may be a result of colonization events coupled with genetic drift, founder effects, and strong natural selection. Additional factors include the self-compatible reproductive system and the long-lived perennial habit.     

Trophic Structure of One Deep-sea Benthic Fish Community in the Eastern Canadian Arctic: Application of Food, Parasites and Multivariate Analysis

Synopsis As new arctic marine fisheries develop there is need for a comprehensive ecosystem approach to long-term management. This approach recognizes the importance of community interactions such as food web structure and trophic patterns. We determined whether hierarchical clustering (guild formation) is an effective method of trophic evaluation in deep-sea Artic fish communities using stomach content and parasite data with size class, and evaluated the application of endohelminth communities (parasite species transmitted in the food) as indicators of trophic status. Cluster analysis using food group abundance with size class of fish revealed the presence of 11 guilds within the community, however the same analysis using parasite data showed little correlation between food and parasites. Redundancy analysis (RDA) within the 11 guilds also revealed no significant correlations between food group and parasite abundance suggesting that this type of ordination is not suited for environments containing mainly generalist feeders. RDA of individual taxa without a priori guild designation found that taxa in benthic deep-sea communities are defined by their ability to exploit prey species in more than one habitat zone. Benthic fish species were significantly correlated with benthic food groups and parasites that utilize benthic intermediate hosts whereas benthopelagic–pelagic species fed on a higher diversity of prey species and were infected by a larger number of non-host specific parasites. Eigenanalysis and Monte Carlo results showed that parasites and food groups are highly correlated, indicating that parasite community analysis is an effective tool for predicting feeding strategies in Arctic marine environments. It also suggests that in most cases endoparasite infections alone could be used for trophic evaluation in the absence of stomach content data.     

Supplementary winter feeding of wild red deer Cervus elaphus in Europe and North America: justifications, feeding practice and effectiveness

1. Supplementary winter feeding of game animals, and particularly deer, is a common practice throughout northern (continental) Europe and parts of North America. Feeding is normally associated with maintaining high densities of animals for hunting, in terms of: (i) maintaining or increasing body weights and condition overwinter; (ii) improving reproductive performance and fertility; (iii) increasing overwinter survival; and (iv) reducing levels of damage caused to agriculture and forestry or the natural heritage. We consider the balance of evidence on the effectiveness of winter feeding of red deer Cervus elaphus in achieving these objectives. Where that evidence is equivocal, we attempt to reconcile apparent contradictions to evaluate the circumstances under which winter feeding may or may not be effective. 2. In general, feeding of red deer on open range appears to have relatively little effect on body weights or fecundity. Effects on increasing antler size and quality are variable and seem to depend on the degree to which animals may be mineral limited on native range. Effects on survival are similarly ambiguous. It is apparent, however, that to be effective in reducing mortality, any supplementation is required early in the season and not simply when heavy mortalities are already being experienced. If provision of supplementary foods is delayed until animals are perceived already to be in poor condition, such feeding may have little effect. 3. One of the primary goals of winter feeding in both Europe and the USA has become the prevention of environmental damage, particularly damage to commercial and native forests, while maintaining deer populations at densities suitable for hunting. Again, empirical evidence for effectiveness in this regard is inconclusive, with some studies showing a decrease in damage caused, some showing no effect and others showing a significant increase in local impact. 4. There are equally a number of problems associated with the provision of supplementary feeds overwinter. Those animals which come to the feeding stations may develop a reliance on the food supplement provided, reducing intake of natural forages to near zero; where feed provided is less than 100% of daily requirement, such animals may regularly lose, rather than gain condition. Feed provision is also extremely uneven at such feeding stations; dominant stags displace younger stags and hinds from the feed provided until they have themselves finished feeding. Concentrations of high densities of animals around small feed‐areas may also increase the risk of infection and lead to development of high parasite burdens. 5. In an attempt to assess the current status and distribution of supplementary winter feeding in Scotland, a questionnaire was circulated to a number of individual across the country. Results of this survey are summarized and conclusions presented on the likely effectiveness of current feeding practices in achieving their aims.     

Intraspecific competition and density dependence of food consumption and growth in Arctic charr

1. Intraspecific competition for restricted food resources is considered to play a fundamental part in density dependence of somatic growth and other population characteristics, but studies simultaneously addressing the interrelationships between population density, food acquisition and somatic growth have been missing. 2. We explored the food consumption and individual growth rates of Arctic charr Salvelinus alpinus in a long-term survey following a large-scale density manipulation experiment in a subarctic lake. 3. Prior to the initiation of the experiment, the population density was high and the somatic growth rates low, revealing a severely overcrowded and stunted fish population. 4. During the 6-year period of stock depletion the population density of Arctic charr was reduced with about 75%, resulting in an almost twofold increase in food consumption rates and enhanced individual growth rates of the fish. 5. Over the decade following the density manipulation experiment, the population density gradually rose to intermediate levels, accompanied by corresponding reductions in food consumption and somatic growth rates. 6. The study revealed negative relationships with population density for both food consumption and individual growth rates, reflecting a strong positive correlation between quantitative food intake and somatic growth rates. 7. Both the growth and consumption rate relationships with population density were well described by negative power curves, suggesting that large density perturbations are necessary to induce improved feeding conditions and growth rates in stunted fish populations. 8. The findings demonstrate that quantitative food consumption represents the connective link between population density and individual growth rates, apparently being highly influenced by intraspecific competition for limited resources.     

Population expansion and breeding success of Bearded Vultures Gypaetus barbatus in the French Pyrenees: results from long‐term population monitoring

Based on monitoring of Bearded Vultures over 24 years in the French Pyrenees, we assessed factors explaining temporal and spatial variations in numbers and breeding performance. The number of territorial pairs increased throughout the study period from 16 in 1994 to 44 in 2017. No significant negative trends in mean productivity (fledglings per territorial pair) were detected with increasing population size. Colonization probability increased significantly with breeding population size the previous year and with the regular provision of supplementary food in the territory the winter when colonization occurred. Colonization of new territories simultaneously increased the distribution range and local densities, but we found no effect of number of near neighbours on productivity. Pairs having bred less than 5 years together had a much lower probability of laying clutches, and higher lay rates were observed inside or close to protected areas after accounting for pair‐bond length, so productivity of territories inside protected areas was significantly higher. Nest success decreased with advanced lay date and increased with winter food abundance. Nesting failures in the study area were frequently associated with harsh weather. Additionally, disturbance by human activities was the second most important identified cause of breeding failure. The probability of failing due to disturbance was higher in western areas (where breeding areas are more accessible to humans), outside protected areas, and has increased with time. After a failure due to disturbance, there was a significantly higher probability of not producing a clutch the following year as compared with pairs that had not failed or had failed due to other causes, indicating deferred effects of disturbance. Our results show the benefits of conservation management actions, such as implementation of protected areas or designed supplementary food programmes in winter, to help range expansion. On the other hand, we did not find a significant effect of winter supplementary food on productivity. Management of feeding sites should be adapted to more specific planning, being used only in areas where natural food availability is scarce, avoiding its use close to breeding sites when juveniles disperse, and targeted mainly to help range expansion. Our results also highlight the importance of maintaining or enhancing good populations of wild ungulates and regulating human activities around nesting sites of this threatened species.