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The popularity and maintenance of the Iranian gray squirrel have been increasing in the last decade. However, due to the special conditions of keeping and the exotic nature of this animal, the possibility of transmission of pathogenic objects such as bacterial, fungal, and parasitic infections and the transmission of many common diseases between humans and animals are raised in a case study of a collar infestation. The female squirrel was observed to be 65 days old and morphological examinations revealed the possibility of infestation with Hoploleura sciuricola lice. Previously, there were no reports of infestation with this louse in Iran. To accurately determine the sex and species of this louse, two pairs of primers designed from the mitochondrial gene (COX-I) that had protected regions in the genus of this louse were used, which led to the confirmation of the identity of the infestation and the first report of the existence of this louse in Iran was confirmed. [ABSTRACT FROM AUTHOR]

Skeletal injuries, especially broken bones, diminish physical mobility of animals, and they may affect an individual’s ability to obtain food and to evade predators. We quantified and compared healed fractures in two sympatric species of tree squirrels (Sciurus niger Linnaeus, 1758 and S. carolinensis Gmelin, 1788) that differ in body size (mass) and locomotor mode. We assessed the number and location of healed fractures in two urban populations of S. carolinensis and in individuals of both species from one rural location. We found a higher-thanexpected proportion of healed fractures in older animals of both species. However, we detected no deviations from expected in the number of healed fractures between the two species or between sexes within a species. Urban populations of S. carolinensis exhibited significantly higher-than-expected proportions of healed fractures, and they were approximately 4.5 times more likely to have a healed injury as compared to rural S. carolinensis. Our findings suggest that S. carolinensis in urban populations experience a higher rate of injury and/or a higher rate of survival after injury than those in rural populations. [ABSTRACT FROM AUTHOR]

A Northern Goshawk (Accipiter gentilis) was observed following an American Marten (Martes americana). The marten's attempts to capture a Gray Squirrel (Sciurus carolinensis) forced the squirrel into the open where the goshawk repeatedly attempted to capture it as the marten chased it through the trees. Attacks on prey flushed by heterospecific predators have been reported for a few other raptors, but this type of interaction has not been reported previously for either goshawks or martens. [ABSTRACT FROM AUTHOR]

Eastern gray squirrels (Sciurus carolinensis) exhibit a variety of color morphs, including black. In the USA and UK, a common folk belief is that black squirrels are more aggressive than squirrels of other colors. We tested the biological basis of that belief using data from the 2018 Central Park squirrel census. Contrary to the belief, black squirrels do not chase other squirrels more often than do conspecifics of other colors. Black and non-black squirrels were equally likely to approach people for food and to display indifference to human presence, but black squirrels were more likely than non-black squirrels to flee from people. Although other research has found that aggression among squirrels increases when they live in higher population densities, black squirrels were no more aggressive than non-black squirrels despite the fact that they were sighted in parts of Central Park with higher squirrel population densities than other locations. [ABSTRACT FROM AUTHOR]

Invasive species are among the major driving forces behind biodiversity loss. Gene drive technology may offer a humane, efficient and cost-effective method of control. For safe and effective deployment it is vital that a gene drive is both self-limiting and can overcome evolutionary resistance. We present HD-ClvR in this modelling study, a novel combination of CRISPR-based gene drives that eliminates resistance and localises spread. As a case study, we model HD-ClvR in the grey squirrel (Sciurus carolinensis), which is an invasive pest in the UK and responsible for both biodiversity and economic losses. HD-ClvR combats resistance allele formation by combining a homing gene drive with a cleave-and-rescue gene drive. The inclusion of a self-limiting daisyfield gene drive allows for controllable localisation based on animal supplementation. We use both randomly mating and spatial models to simulate this strategy. Our findings show that HD-ClvR could effectively control a targeted grey squirrel population, with little risk to other populations. HD-ClvR offers an efficient, self-limiting and controllable gene drive for managing invasive pests. [ABSTRACT FROM AUTHOR]

Human activities are changing the environments that animal communities utilize, altering competition and co-existence dynamics as well as changing species distributions. A global consequence of human activity is increased woody cover, which changes environmental conditions on landscape, local, and fine spatial scales. These multi-scale processes are likely to change species interactions and distributions in unexpected ways. To elucidate these effects, we investigated the co-occurrence of two interacting species in a rapidly changing ecosystem. Eastern fox (Sciurus niger) and gray (Sciurus carolinensis) squirrels occur sympatrically throughout the southeastern United States. We used single-season, two-species occupancy modeling to understand what factors influence competition between the squirrels at three spatial scales. We found evidence that fox and gray squirrels compete at fine scales but not at local and landscape scales. The best model to explain fox and gray squirrel co-occurrence at fine scales was an additive fine-scale understory and tree canopy closure model. Increased fine-scale canopy closure correlated with increased fox and gray squirrel occupancy, while increased fine-scale understory cover correlated with decreased gray and fox squirrel occupancy. Fox squirrel occupancy probability declined in the presence of gray squirrels. The intensity of interaction was modified by fine-scale canopy cover and understory density. These findings support the hypothesis that species interactions can be an important factor in structuring biotic communities; however, the strength of the effect changes across spatial scales. Our results support the importance of considering species interactions at multiple scales when predicting and addressing changes in community composition in human modified and managed systems.

The results of the current study showed that the liver of H. javanicus appeared as large lobulated organ divided into six distinct lobes, that filled the cranial region and little extended to the middle region of abdominal cavity. On the other hand, liver of S. carolinensis laid against the diaphragm, occupied the cranial region of the abdominal cavity and consisted of five lobes. The liver is surrounded with a thin capsule of dense regular collagenous connective tissue and few numbers of smooth muscles fibers can be seen in the capsule that covered the squirrel liver. The liver parenchyma divided into a large number of interconnected hepatic lobules marked only by the abundant amount of connective tissue bordered the triads, and within these lobules, polyhedral shaped hepatocytes are arranged as cords of one cell thick. The liver cords are enclosed by irregular hepatic sinusoids and ordered in radial fashion around the central vein. The portal areas are consisting of branches of the hepatic portal vein and hepatic artery as well as (1-4) branches of the bile duct that appear in different sizes. Cuboidal epithelium type is lined the small branches of these ducts, while the large sized of them is lined by columnar epithelium type, in which the goblet cells appeared to be more frequently and clearer in H. javanicus than S. carolinesis. In weasel, sometimes the triad structures of large and small sized portal areas are embedded together in one abundant mass of connective tissue. [ABSTRACT FROM AUTHOR]

Animals change their daily activity patterns in response to season, food availability and the presence of competitors. Competition may be an important driver of a species' daily activity pattern, as animals manage conflict by avoiding each other temporally. We evaluated how vegetation structure and the presence of competitors changed the daily activity patterns of closely related fox squirrels, Sciurus niger, and grey squirrels, Sciurus carolinensis. We monitored squirrel activity in north and central Florida using passive game cameras at two spatial scales: local and point. To understand how seasonality and competition interact to drive behaviour, we compared squirrel activity during the leaf-off (1 January – 15 March) and leaf-on (16 March – 1 July) seasons. We tested for a relationship between squirrel activity and canopy cover by fitting a von Mises kernel distribution. To test how season and competition affected squirrel behaviour, we compared activity by computing a kernel density overlap function, ranging from 0 (no overlap: the squirrels are never active at the same time) to 1 (complete overlap: the squirrels have identical activity patterns). We found that daily squirrel behaviour was not influenced by canopy cover (P = 0.61). Fox squirrels had a single activity peak occurring around midday. In contrast, grey squirrels had a bimodal activity pattern with peaks shortly after sunrise and before sunset. The intensity of this partitioning existed on a gradient and changed with season and the presence of competitors. Fox and grey squirrel daily patterns overlapped the most when they were allopatric in the leaf-on season (overlap = 0.70, P < 0.001) and the least while sympatric in the leaf-on season (overlap = 0.24, P < 0.08). This ephemeral response to competition highlights that various axes of resource partitioning can promote coexistence between closely related species. Highlights • We examined daily activity patterns of competing grey and fox squirrels. • Squirrel behaviour was not influenced by canopy cover. • Fox squirrels had a single activity peak around midday. • Grey squirrel activity peaked shortly after sunrise and before sunset. • Temporal partitioning existed on a gradient and varied with season and competition. [ABSTRACT FROM AUTHOR]

Native red squirrels Sciurus vulgaris in Great Britain and Ireland are threatened by alien grey squirrels S. carolinensis through exploitation competition and spillover of squirrelpox virus (SQPV). By accelerating the replacement of red squirrels by the invader, SQPV represents a fundamental factor to consider when planning management and conservation strategies. In mainland Europe, grey squirrels introduced to Italy threaten the survival of the whole continental red squirrel population, but no extensive surveys for SQPV presence have been carried out in the region. We therefore investigated SQPV infection in north Italian grey squirrel populations through a combination of serological and molecular methods. Firstly, we analysed sera from 285 individuals through an enzyme‐linked immunosorbent assay (ELISA) to detect antibodies against SQPV. Secondly, a PCR designed to amplify a segment of the G8R SQPV gene was carried out on DNA extracted from swabs and skin tissue samples from a second set of 66 grey squirrels. ELISA tests identified four reactors (1.4%), but the subsequent PCR survey did not detect any SQPV DNA. Based on the low prevalence observed and on PCR results, we believe that the four suspected positives were the result of an ELISA cross‐reaction following exposure to another pox virus. Considering sample size and performances of the two methods, confidence of freedom from SQPV resulted above 99.9%. However, because of the severe impact of SQPV on red squirrels, we recommend the implementation of a passive surveillance plan for the early detection of an SQPV emergence in continental Europe. Squirrelpox virus transmitted by alien grey squirrels played a crucial role in the decline of native red squirrels in Great Britain and Ireland. It is still unknown whether the virus is circulating in Italy too, where it could potentially threaten the whole European red squirrel population. We extensively surveyed grey squirrels introduced to Italy for squirrelpox virus infection through a combination of serological and molecular methods, but did not find any evidence of the disease in the area. We discuss the implications of this absence and recommend the activation of passive surveillance plans to avoid any disease emergence that could threaten native squirrels survival. Photo credit: Sandro Bertolino. [ABSTRACT FROM AUTHOR]

The Open Field Test (OFT) and Mirror Image Stimulation (MIS) are used to measure behaviours related to an individual's personality. These tests, carried out in a same novel arena, have been used for different taxa, but only a few papers underline the importance of method validation. Here we investigate how Eurasian red squirrels (Sciurus vulgaris) and Eastern grey squirrels (Sciurus carolinensis) behave during OFT and MIS. Next, we compare the performance between three analytical methods: the Principal Component Analysis (PCA), the Factor Analysis (FA) and an expert-based (EB) method. The EB approach classifies behaviours in groups relating on researchers' knowledge and returns personality-trait values for each individual facilitating comparisons over studies and/or with new datasets. The comparison between the three methods gave similar results and high repeatabilities in some expert-based personality traits as well as PCA components and FA factors, showing that all three methods were valid to measure activity using OFT (both species) and sociability using MIS (grey squirrel). Repeatabilities of the other traits were less strong. Proportion of time spent in different behaviours did not differ with test duration, since shorter tests yielded valid measures of individual differences in personality. Shorter tests reduce operator time in the field, and are likely to reduce stress and arena-habituation of the animals. Test sequence affected the outcome of OFT: squirrels tested for the first time were more active than squirrels tested a second time. For the two squirrel species investigated, we recommend an OFT of 4 min and a MIS test of three and suggest to test an individual no more than 2 times per season with at least 2 months between repetitions. [ABSTRACT FROM AUTHOR]

This study aim at reporting landmarks and quantitative aspect of the wild diurnal squirrel reproductive tract. Knowledge on the reproductive system of this species may give better understanding on the reproductive physiology and production. Five squirrels were used for this study. The live body weight and length were 391.57 ± 22.561 g and 52.62 ± 4.559 cm respectively. The length of the ovary and the whole reproductive tract were (0.96 ± 0.128 cm right, 0.91 ± 0.173 cm left) and 7.603 ± 0.120 cm respectively. Length of the various segments were significantly different at p<0.05. Gross features indicated long fallopian tubes or oviduct, separated at the external uterine bifurcation. The oviduct is ill-define to differentiate the ampulla from a short isthmus. The ampulla is longer, wider than isthmus and the reproductive system is of the bicornuate type. [ABSTRACT FROM AUTHOR]

Abstract Information on the status of biodiversity is crucial for species conservation and management. Large scale assessments are only feasible through citizen science but some taxa are poorly monitored because few people specialise in them. We explore alleviating this problem by using data collected for poorly monitored species as an add-on to existing bird surveys. Since 1995, participants in the annual Breeding Bird Survey have recorded the abundance of mammals during their surveys. We demonstrate the value of these data by developing spatial models of relative abundance for nine common and easily detected mammal species. Rabbit, brown hare and mountain hare all showed widespread declines. Conversely, deer showed increases throughout their ranges, with the exception of the red deer whose population was predominantly stable. The grey squirrel continues to increase in several areas. The red fox, the only carnivore with enough data, showed significant large declines. The collection of data on taxa other than the primary target has particular merit where the secondary taxa can be detected effectively by methods devised for the core survey. In such cases the data are inexpensive and inherit some of the benefits of the underlying structure and power of the core survey. However, the efficacy of the primary study design may vary for the members of secondary taxa and may not be temporally or spatially suitable for all of them. Although more volunteer training may be required, there are also opportunities to engage and enthuse people about conservation issues of other species groups. [ABSTRACT FROM AUTHOR]

Seeds of many hardwood trees are dispersed by scatter-hoarding rodents, and this process is often mediated by the traits of seeds. Although numerous studies have linked seed traits to seed preference by rodents, little is known about how rodents forage for seeds when multiple desirable and undesirable seed traits are available simultaneously. Here, we adopt a novel method of designing choice experiments to study how eastern gray squirrels (Sciurus carolinensis) select for 6 traits (caloric value, protein content, tannin concentration, kernel mass, dormancy period and toughness of shell) among seeds. From n = 426 seed-pair presentations, we found that squirrels preferentially consumed seeds with short dormancy or tougher shells, and preferentially cached seeds with larger kernel mass, tougher shells and higher tannin concentrations. By incorporating random effects, we found that squirrels exhibited consistent preferences for seed traits, which is likely due to the fitness consequences associated with maintaining cached resources. Furthermore, we found that squirrels were willing to trade between multiple traits when caching seeds, which likely results in more seed species being cached in the fall. Ultimately, our approach allowed us to compute the relative values of different seed traits to squirrels, despite covariance among studied traits across seed species. In addition, by investigating how squirrels trade among different seed traits, important insights can be gleaned into behavioral mechanisms underlying seed caching (and, thus, seed survival) dynamics as well as evolutionary strategies adopted by plants to attract seed dispersers. We describe how discrete choice experiments can be used to study resource selection in other ecological systems. [ABSTRACT FROM AUTHOR]

Abstract: Although the effects of bird feeding on avian species have been extensively examined, few studies evaluate the indirect effects of bird feeding on non‐target taxa. Bird seed could provide direct nourishment to several mammalian species (e.g., Lagomorpha, Rodentia, and Cetartiodactyla), potentially altering their distribution and behavior with possible unintended consequences for some avian populations, particularly those not directly benefiting from the resource. To examine how bird feeders may influence the presence and behavior of mammals, we used camera traps to quantify differences in the distribution and richness of mammal species frequenting sites with bird feeders and control sites (lacking feeders) in Ithaca, New York, USA. We recorded 15,684 images capturing 12 mammal species with gray squirrel (Sciurus carolinensis) and raccoon (Procyon lotor) detected significantly more often at feeder sites than at control sites. Detections of white‐tailed deer (Odocoileus virginianus) marginally increased near feeders whereas detections of several carnivorous species were unrelated to the presence of bird feeders. We recorded larger gray squirrel and raccoon group sizes and greater mammal richness at feeder sites than at nearby control sites. We detected squirrels and raccoons less when snow covered the ground than on snow‐free days. Ambient temperature was not a strong predictor of mammal detections. Camera trapping revealed strong, species‐specific patterns in the timing of daily visitation to areas with feeders. Because many mammals depredate bird nests, the local increases in mammal richness and activity near bird feeders may create an ecological trap for avian species nesting in close proximity to supplemental feeding stations. [ABSTRACT FROM AUTHOR]

Shared enemies may instigate or modify competitive interactions between species. The dis-equilibrium caused by non-native species introductions has revealed that the outcome of such indirect interactions can often be dramatic. However, studies of enemy-mediated competition mostly consider the impact of a single enemy, despite species being embedded in complex networks of interactions. Here, we demonstrate that native red and invasive grey squirrels in Britain, two terrestrial species linked by resource and disease-mediated apparent competition, are also now linked by a second enemy-mediated relationship involving a shared native predator recovering from historical persecution, the European pine marten. Through combining spatial capture-recapture techniques to estimate pine marten density, and squirrel site-occupancy data, we find that the impact of exposure to predation is highly asymmetrical, with non-native grey squirrel occupancy strongly negatively affected by exposure to pine martens. By contrast, exposure to pine marten predation has an indirect positive effect on red squirrel populations. Pine marten predation thus reverses the welldocumented outcome of resource and apparent competition between red and grey squirrels. [ABSTRACT FROM AUTHOR]

Behavioural flexibility has been argued to be an evolutionarily favourable trait that helps invasive species to establish themselves in non-native environments. Few studies, however, have compared the level of flexibility (whether considered as an outcome or as a process) in mammalian invaders and related native species. Here, we tested whether flexibility differs between groups of free-ranging invasive eastern grey squirrels, Sciurus carolinensis , and native Eurasian red squirrels, Sciurus vulgaris , in the U.K., using an easy and a difficult food extraction task. All individuals of both species showed flexibility, at the outcome level, in solving the easy task and solution time was comparable between species across a series of successes. A higher proportion of grey squirrels than red squirrels solved the difficult task. However, for those squirrels that did solve the task, solving efficiency was comparable between species on their first success, and a few red squirrels outperformed the grey squirrels in subsequent successes. Between-species analysis showed that instantaneous flexibility, flexibility at the process level that was measured as the rate of switching between tactics after a failed attempt, was higher in red squirrels than in grey squirrels. Within-species analysis also revealed that red squirrel problem solvers showed higher flexibility at the process level than their nonsolver counterparts. Nonsolvers also failed to make ‘productive’ switches (switching from ineffective to effective tactics). Together, the results suggest that problem-solving ability overlaps in the two species, but is less variable, and on average higher, in grey squirrels than in red squirrels. The superior behavioural flexibility of the grey squirrels, shown here by success at problem solving, may have facilitated their invasion success, but it may also have resulted from selective pressures during the invasion process. [ABSTRACT FROM AUTHOR]

The damage caused when grey squirrels strip the outer bark off trees and ingest the underlying phloem can result in reduced timber quality or tree death. This is extremely costly to the UK forestry industry and can alter woodland composition, hampering conservation efforts. The calcium hypothesis proposes that grey squirrels ingest phloem to ameliorate a seasonal calcium deficiency. Calcium in the phloem predominantly takes the form of calcium oxalate (CaOx), however not all mammals can utilise CaOx as a source of calcium. Here, we present the results of a small-scale study to determine the extent to which grey squirrels can utilise CaOx. One of three custom-made diets containing calcium in varying forms and quantities (CaOx diet, Low-calcium carbonate (Ca CO3) diet and Control diet) were fed to three treatment groups of six squirrels for 8 weeks. Bone densitometric properties were measured at the end of this time using peripheral quantitative computed tomography and micro-computed tomography. Pyridinoline-a serum marker of bone resorption-was measured regularly throughout the study. Bone mineral density and cortical mineralisation were lower in squirrels fed the CaOx diet compared to the Control group but similar to that of those on the Low-calcium diet, suggesting that calcium from calcium oxalate was not effectively utilised to maintain bone mineralisation. Whilst no differences were observed in serum pyridinoline levels between individuals on different diets, females had on average higher levels than males throughout the study. Future work should seek to determine if this apparent lack of ability to utilise CaOx is common to a large sample of grey squirrels and if so, whether it is consistent across all areas and seasons. [ABSTRACT FROM AUTHOR]

The goals of this study were to map the distribution of the invasive eastern gray squirrel, Sciurus carolinensis, in California as of 2015 and to assess range expansion since the first documented sightings within the state. Range maps exist, but the last update by the California Department of Fish and Wildlife was in 2007. An assessment of the rate of range expansion over time has not been conducted, but comparisons between the locations of initial sightings and the current distribution are included. Location data were obtained from museum specimens, wildlife rehabilitation centers, a roadkill database, and researchgrade citizen observations. Range maps were produced with ArcGIS software. Populations of eastern gray squirrels are currently concentrated around Sacramento and Davis, the western side of San Francisco Bay, within as well as north and east of Santa Cruz, within Monterey, north of the Golden Gate Bridge through Marin County as well as around Santa Rosa, and around the Bellota/Stockton area. Isolated populations on the eastern side of San Francisco Bay occur around Berkeley, Hayward, and Pleasanton. Observations extend into the foothills of the Sierra Nevada Mountain Range from north of the American River to south of the San Antonio River. We suggest that the eastern gray squirrel might become more damaging to the two native diurnal species of tree squirrels in California, Sciurus griseus and Tamiasciurus douglasii, than the introduced eastern fox squirrel (Sciurus niger). [ABSTRACT FROM AUTHOR]

ABSTRACT Mercury (Hg), Selenium (Se), and Arsenic (As) found in coal combustion wastes (CCW) and radionuclides released from anthropogenic activities present potential environmental and human health concerns. Despite the widespread harvest and consumption of wildlife by recreational hunters, game species are not subject to the same safety testing as commercially marketed livestock; thus, there are few data available regarding contaminant concentrations in many commonly harvested wildlife. We sampled feral pigs ( Sus scrofa; invasive wild pigs), gray squirrels ( Sciurus carolinensis), and waterfowl from relatively uncontaminated habitats and areas of contamination to quantify levels of trace elements and radiocesium (137Cs) in muscle and liver tissues for assessment of potential human health risks from the consumption of game. Species collected at a CCW ash basin consistently had levels of selected trace elements, particularly Se, above concentrations considered toxic to waterfowl, suggesting CCW may be an important pathway for wildlife, and subsequently human exposure to this element. Similarly, we observed elevated concentrations of 137Cs in wildlife collected in or near aquatic ecosystems with histories of operational releases of radionuclides. The majority of tissue samples analyzed were below elemental levels known to adversely affect wildlife health and 137Cs levels were below European Economic Community limits for human consumption established following the 1986 Chernobyl accident. Waterfowl, however, had levels of several elements of interest (Se and Hg) that could be of health concern to the birds, especially individuals collected from areas with known contamination, or human consumers of the birds. Given the high levels of trace element burdens we observed in waterfowl collected from ash basins, and the common occurrence of similar surface impoundments throughout much of the globe, wide-scale sampling for contaminants in waterfowl within or across migratory flyways appear to be greatly needed to better understand routes of contaminant movement and potential areas (or species) with elevated contamination risk to waterfowl and hunters. © 2017 The Wildlife Society. [ABSTRACT FROM AUTHOR]

The grey squirrel is an invasive pest species in the United Kingdom and populations are controlled to protect timber crops and native fauna. Although animals are culled using a variety of methods, there are few data available on the relative efficiency of different trap designs, and in particular spring traps. We compared grey squirrel captures in Magnum 116 spring-traps set within Fineren boxes against captures in a single entry live capture trap design. Trapping was conducted in mature mixed woodland in North Wales. No significant difference in the frequency of grey squirrel captures or body mass of trapped individuals between trap designs was observed. Despite the Fineren box design limiting access by non-target species, by-catch was recorded. We make recommendations for future research to minimise this and also compare our results for Magnum 116 traps with data available on captures in Fenn IV spring traps. The findings have broad relevance to the control of grey squirrels across their wider international invasive range. [ABSTRACT FROM AUTHOR]

In mammals, expression of certain melanocortin receptor ligands is correlated with both dark pigmentation and increased stress resistance and higher levels of aggression. Though many studies of captive and laboratory animals have explored this pleiotropic interaction, relatively few studies of animal behavior have occurred in free-living wild animals. This playback study focused on the antipredator behavior differences between melanistic and gray morphs of eastern gray squirrels ( Sciurus carolinensis) in Hiram, Ohio. Vigilance, tail flagging, freezing, and escape behaviors were recorded in response to digital playback of an American robin call, a chickadee call, a car alarm, a buzzer, or one of two different red-tailed hawk calls. All squirrels exhibited increased antipredator behavior after hearing increasingly threatening stimuli. Consistent with prior findings in other species with color polymorphism, gray morphs were more likely to escape after hearing a threatening call. A growing body of evidence indicates it is possible to study pleiotropic effects of genes in free living animals. [ABSTRACT FROM AUTHOR]

Behavioural flexibility allows animals to adjust their behaviours according to changing environmental demands. Such flexibility is frequently assessed by the discrimination-reversal learning task. We examined grey squirrels' behavioural flexibility, using a simultaneous colour discrimination-reversal learning task on a touch screen. Squirrels were trained to select their non-preferred colour in the discrimination phase, and their preferred colour was rewarded in a subsequent reversal phase. We used error rates to divide learning in each phase into three stages (perseveration, chance level and 'learned') and examined response inhibition and head-switching during each stage. We found consistent behavioural patterns were associated with each learning stage: in the perseveration stage, at the beginning of each training phase, squirrels showed comparable response latencies to correct and incorrect stimuli, along with a low level of head-switching. They quickly overcame perseveration, typically in one to three training blocks. In the chance-level stage, response latencies to both stimuli were low, but during initial discrimination squirrels showed more head-switches than in the previous stage. This suggests that squirrels were learning the current reward contingency by responding rapidly to a stimulus, but with increased attention to both stimuli. In the learned stage, response latencies to the correct stimulus and the number of head-switches were at their highest, whereas incorrect response latencies were at their lowest, and differed significantly from correct response latencies. These results suggest increased response inhibition and attention allowed the squirrels to minimise errors. They also suggest that errors in the 'learned' stage were related to impulsive emission of the pre-potent or previously learned responses. [ABSTRACT FROM AUTHOR]

Ornamental farming is the main source of future diffusion of exotic species, but containment measures for these species are often criticized or disapproved by public opinion, in particular in urban areas in all the European countries. In this paper, the social acceptability of rational solutions for this problem is discussed, thus keeping in mind the importance of the conservation of native species and the impact of exotic ones on agriculture and farmed species. Currently, the most problematic alien vertebrate species in Italy are the gray squirrel, the coypu, the cottontail rabbit and the American mink, while the Rose-ringed parakeet and monk parakeet are considered to be the potentially most dangerous alien bird species. The effects of the presence of these species include competition with autochthonous species, damage to agricultural crops and diffusion of pathologies. Ornamental animal farming is an emerging activity in Italy and throughout Europe, and it is likely that it will be the main source of the introduction of exotic species. The possible solutions to exotic species diffusion are: improving current laws, shared strategies with neighbouring countries, eradication and management of exotic species. This review deals with management of the most invasive terrestrial mammals and birds in Italy as well as with some social and ethical implications. [ABSTRACT FROM AUTHOR]

Seed predation and rodent foraging behaviors depend on frequency of available seeds and seed traits. However, the interaction of frequency of seed availability and seed traits adds a new level of complexity to granivore-seed dynamics. We conducted experiments with eastern gray squirrels (Sciurus carolinensis) designed to elucidate the frequency × trait interaction. We hypothesized that frequency-dependent caching should occur only among pairs of seeds that are relatively similar in attributes that affect their perceived value as a storable food item. We also tested whether caching decisions were dependent on seeds already cached, a variable rarely considered in seed dispersal studies. Frequency-dependent seed caching occurred when seeds of relatively similar value (Juglans regia and Castanea mollissima) were paired. For this seed pair, caching decisions by S. carolinensis were dependent on seeds already cached such that squirrels tended to cache seeds that were either rare in the environment or in the cache. When seeds of very different caching values were paired (Juglans nigra and Corylus americana), a strong preference for the high-value seed was observed, but no frequency-dependent selection. We conclude that in pairings of seeds of differential caching value, the highly preferred seed is cached regardless of frequency of availability. In contrast, when seeds of similar value are paired, rarer (more common) seeds are cached at a higher (lower) rate than expected, and this behavior potentially stabilizes seed survival across available seed types leading to increased tree diversity. Our results indicate that caching of seeds by squirrels, and by implication recruitment of seedlings into plant populations, is likely driven by complex interactions between the relative frequency of seeds and their traits. We expect similar patterns to occur in any system in which foragers select among resource types that vary in perceived value. [ABSTRACT FROM AUTHOR]

BACKGROUND Eradication of invasive alien species supports the recovery of native biodiversity. A new European Union Regulation introduces obligations to eradicate the most harmful invasive species. However, eradications of charismatic mammals may encounter strong opposition. Considering the case study of the eastern grey squirrel ( Sciurus carolinensis Gmelin, 1788) in central Italy, we developed a structured decision-making technique based on a Bayesian decision network model and explicitly considering the plurality of environmental values of invasive species management to reduce potential social conflicts. RESULTS The model identified priority areas for management activities. These areas corresponded to the core of the grey squirrel range, but they also included peripheral zones, where rapid eradication is fundamental to prevent the spread of squirrels. However, when the model was expanded to integrate the attitude of citizens towards the project, the intervention strategy slightly changed. In some areas, the citizens' support was limited, and this resulted in a reduced overall utility of intervention. CONCLUSION The suggested approach extends the scientific basis for management decisions, evaluated in terms of technical efficiency, feasibility and social impact. Here, the Bayesian decision network model analysed the potential technical and social consequences of management actions, and it responded to the need for transparency in the decision-making process, but it can easily be extended to consider further issues that are common in many mammal eradication programmes. Owing to its flexibility and comprehensiveness, it provides an innovative example of how to plan rapid eradication or control activities, as required by the new EU Regulation. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Eastern gray squirrels use three acoustically distinct vocalizations, namely kuks, quaas and moans, in their alarm calling bouts. Although moans are highly specific to aerial threats, kuks and quaas show no clear association with either terrestrial or aerial predator type when simply examining their presence or absence in an entire bout of vocal signaling. Here we examine the relationship between alarm call composition (the presence and rate of kuks, quaas and moans) and the type of stimulus eliciting the alarm call (aerial or terrestrial). When the first 30 sec or second 30 sec of calling is examined, the presence of kuks, quaas (only used in the second 30-sec period), and moans are all associated with stimulus type. Kuks and quaas are usually used in response to terrestrial stimuli and moans are used exclusively in response to aerial stimuli. The relationship between call composition and stimulus is even stronger when considering the rate of calls. In the first 60 sec of calling, all three vocalizations differ in rate depending on threat type, with more kuks and more quaas elicited by terrestrial than aerial stimuli, while moans are not produced at all with terrestrial stimuli. Overall rates of calling, combining all three vocalization types, also differed by stimulus type. The median number of vocalizations in the first 60 sec of calling bouts elicited by terrestrial threats was nearly 3 times greater than in calling bouts elicited by aerial threats. The alarm calls of gray squirrels are predator-specific, containing significant information on whether a threat is aerial or terrestrial. Further, the rate of each vocalization type in the initial 60 sec of calling bouts provides more information than does only the presence or absence of each vocalization type. [ABSTRACT FROM AUTHOR]

The article focuses on the Squirrel Mapper project which invites students to measure evolution in action by making local observations in rural and urban landscapes about gray and black squirrels. According to the author, this project encourages students to answer questions including the impact of urbanization on squirrel color variation.