Diet of Mute Swans in Lower Great Lakes Coastal Marshes

Abstract: During the past 30 years, nonnative mute swan (Cygnus olor) populations have greatly increased, and continue to increase, in the eastern United States and within the lower Great Lakes (LGL) region. As a result, there is much concern regarding impacts of mute swan on native waterfowl, aquatic plants, and marsh habitats. There are presently only limited dietary data for mute swans in North America and none exist for birds in the LGL region. Thus, in 2001, 2002, and 2004 we collected 132 mute swans from LGL coastal marshes in Ontario, Canada, to determine dietary composition and to evaluate 1) seasonal and sex-related variation in adult diets and 2) age-related dietary differences. Adult diets did not differ among years, collection sites, or seasons, but female diets contained more pondweed spp. (Potamogeton spp.) and less slender naiad (Najas flexilis) and common waterweed (Elodea canadensis) than did diets of males. Adult males, adult females, and cygnets had similar diets during summer and autumn. Overall, mute swan diets mainly consisted of above-ground biomass of pondweed spp., muskgrass (Chara vulgaris), coontail (Ceratophyllum demersum), slender naiad, common waterweed, wild celery (Vallisneria americana), and wild rice (Zizania palustris); below-ground parts of wild celery, sago pondweed (Stuckenia pectinatus), and arrowhead spp. (Sagittaria spp.) were eaten infrequently. Comparison of our findings with those of other diet studies suggested considerable dietary overlap between mute swans and several other species of native waterfowl. Thus, we suggest that mute swans have potential to compete with native waterfowl and impact aquatic plants that are important waterfowl foods within LGL coastal marshes. Further, our results can be used to assess which aquatic plant species may be most impacted by foraging activities of mute swans at other important waterfowl stopover and wintering sites in North America. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):726–732; 2008)     

Sociodemographics of Pet Ownership among Adolescents in Great Britain: Findings from the HBSC Study in England,Scotland, and Wales

The aim of this study was to assess the prevalence of pet ownership among adolescents in Great Britain and identify any sociodemographic differences between pet owners and non-pet owners. A total of 14,328 11-to 15-year-old adolescents from England, Scotland, and Wales were included in the analysis. Results revealed 15-year-old adolescents were significantly more likely than 11-year-old adolescents to own dogs (OR = 1.146, p < 0.001) but less likely to own fish, reptiles, or amphibians (OR = 0.629, p < 0.001), and small mammals (OR = 0.630, p < 0.001). Thirteen-year-olds were significantly more likely than 11-year-olds to own dogs (OR = 1.240, p = 0.021) and birds (OR = 1.299, p = 0.010), but significantly less likely to own fish, reptiles, or amphibians (OR = 0.795, p < 0.001). No gender differences were found. White adolescents were more likely than non-white adolescents to own all pet types. Those living in single-parent families were significantly more likely than those living with two parents to own dogs (OR = 1.186, p = 0.013) and cats (OR = 1.319, p < 0.001). Furthermore, those who reported living in stepfamilies were also more likely to own cats (OR = 1.428, p < 0.001). Adolescents with siblings were more likely to own cats (OR = 1.391, p = 0.001), fish, reptiles, or amphibians (OR = 1.220, p = 0.037) than adolescents without siblings. Adolescents with employed parents (both or one) were significantly more likely than those with unemployed parents to own dogs (OR = 1.414, p = 0.002) and birds (OR = 1.523, p = 0.018). Adolescents from high-affluence families were less likely than adolescents from low-affluence families to own dogs (OR = 0.888, p = 0.037), small mammals (OR = 0.832, p = 0.005), and birds (OR = 0.801, p = 0.046). Furthermore, family affluence differences were found in different pet types. Differences in all pet types and siblings were also found in a proxy measure of attachment to pets. This study provides evidence that pet ownership is related to several sociodemographic factors. These are relevant to take into account when performing HAI studies on adolescents.     

Ethnic minority status and attitudes towards police powers: A comparative study of Great Britain,Northern Ireland and the Republic of Ireland

It is one of the axioms of police research that the relationship between the police and ethnic minorities is, to say the least, problematic. There is now a growing body of empirical research which shows that the relationship is characterized by mutual antipathy. Using recent comparable data from Great Britain, Northern Ireland and the Republic of Ireland, such conventional wisdom is tested in this article by means of ethnic responses to the power of the police in dealing with known criminals. Using multivariate regression analysis, the results suggest that not only is the relationship between ethnic minority status and attitudes towards the power of the police clearly different across these three countries, it also operated in unexpected ways which run directly counter to well‐accepted beliefs about the problematic relationship between the police and members of ethnic minority groups. In other words, for these three societies at least, occupying an ethnic minority group status does not automatically lead to a negative view of the powers that the police should be accorded in the pursuit of known criminals.     

Α comparison of alternative techniques for prediction of the fauna of running-water sites in Great Britain

1. Early versions of the river invertebrate prediction and classification system (RIVPACS) used TWINSPAN to classify reference sites based on the macro-invertebrate fauna, followed by multiple discriminant analysis (MDA) for prediction of the fauna to be expected at new sites from environmental variables. This paper examines some alternative methods for the initial site classification and a different technique for prediction. 2. A data set of 410 sites from RIVPACS II was used for initial screening of seventeen alternative methods of site classification. Multiple discriminant analysis was used to predict classification group from environmental variables. 3. Five of the classification–prediction systems which showed promise were developed further to facilitate prediction of taxa at species and at Biological Monitoring Working Party (BMWP) family level. 4. The predictive capability of these new systems, plus RIVPACS II, was tested on an independent data set of 101 sites from locations throughout Great Britain. 5. Differences between the methods were often marginal but two gave the most consistently reliable outputs: the original TWINSPAN method, and the ordination method semi-strong hybrid multidimensional scaling (SSH) followed by K-means clustering. 6. Logistic regression, an alternative approach to prediction which does not require the prior development of a classification system, was also examined. Although its performance fell within the range offered by the other five systems tested, it conveyed no advantages over them. 7. This study demonstrated that several different multivariate methods were suitable for developing a reliable system for predicting expected probability of occurrence of taxa. This is because the prediction system involves a weighted average smoothing across site groupings. 8. Hence, the two most promising procedures for site classification, coupled to MDA, were both used in the exploratory analyses for RIVPACS III development, which utilized over 600 reference sites.     

Prevalence, distribution and risk associated with tick infestation of dogs in Great Britain

Current concerns over the potential impacts of climate change and the increased movement between countries of people and companion animals on the distribution of ectoparasites, highlight the need for accurate understanding of existing prevalence patterns. Without these future changes will not be detected. Here, the distribution and prevalence of tick infestations of domestic dogs in Great Britain were examined. A total of 173 veterinary practices were recruited to monitor tick attachment to dogs in their local areas between March and October 2009. Practices selected five dogs at random each week from those brought to the surgery and undertook a thorough, standardized examination for ticks. Each veterinary practice participated for 3 months before being replaced. Any ticks identified were collected and a sample sent to the investigators for identification, along with a clinical history of the dog. A total of 3534 dogs were examined; 810 dogs were found to be carrying at least one tick. Ixodes ricinus (Linnaeus) (Acari: Ixodidae) was identified in 72.1% of cases, Ixodes hexagonus Leach in 21.7% and Ixodes canisuga Johnston in 5.6% of cases. Five samples of Dermacentor reticulatus (Fabricius) (Acari: Ixodidae) were also found, adding to the growing evidence that an established population of D. reticulatus now exists in south-eastern England. Almost all the ticks found were adults. Overall, 19.2% of the veterinary practices reported no tick detections, 50% reported that ≥14.9% of the dogs seen were infested and 14.6% reported that >50% of the dogs inspected carried ticks. The estimated incidence of tick attachment was 0.013 per day in March (lowest) and 0.096 per day in June (highest). A number of risk factors affected the likelihood of tick attachment on dogs. Gundog, terrier and pastoral breed groups were more likely to carry ticks, as were non-neutered dogs. Dogs with shorter hair were less likely to have ticks, and dogs were most likely to carry a tick in June. This study is of value because, unusually, it presents the results of a randomized sample of dogs and gives a prevalence which is higher than those previously recorded in Great Britain.     

Variability and profiles of lipophilic toxins in bivalves from Great Britain during five and a half years of monitoring: azaspiracids and yessotoxins

Cefas has been responsible for the delivery of official control biotoxin testing of bivalve molluscs from Great Britain for just over a decade. Liquid chromatography tandem mass spectrometric (LC–MS/MS) methodology has been used for the quantitation of lipophilic toxins (LTs) since 2011. The temporal and spatial distribution of okadaic acid group toxins and profiles in bivalves between 2011 and 2016 have been recently reported. Here we present data on the two other groups of regulated lipophilic toxins, azaspiracids (AZAs) and yessotoxins (YTXs), over the same period. The latter group has also been investigated for a potential link with Protoceratium reticulatum and Lingulodinium polyedra, both previously recognised as YTXs producing phytoplankton.On average, AZAs were quantified in 3.2% of all tested samples but notable inter-annual variation in abundance was observed. The majority of all AZA contaminated samples were found between July 2011 and August 2013 in Scotland, while only two, three-month long, AZA events were observed in 2015 and 2016 in the south-west of England. Maximum concentrations were generally reached in late summer or early autumn. Reasons for AZAs persistence during the 2011/2012 and 2012/2013 winters are discussed. Only one toxin profile was identified, represented by both AZA1 and AZA2 toxins at an approximate ratio of 2 : 1, suggesting a single microalgal species was the source of AZAs in British bivalves. Although AZA1 was always the most dominant toxin, its proportion varied between mussels, Pacific oysters and surf clams.The YTXs were the least represented group among regulated LTs. YTXs were found almost exclusively on the south-west coast of Scotland, with the exception of 2013, when the majority of contaminated samples originated from the Shetland Islands. The highest levels were recorded in the summer months and followed a spike in Protoceratium reticulatum cell densities. YTX was the most dominant toxin in shellfish, further strengthening the link to P. reticulatum as the YTX source. Neither homo-YTX, nor 45−OH homo-YTX were detected throughout the monitored period. 45−OH YTX, thought to be a shellfish metabolite associated with YTX elimination, contributed on average 26% in mussels. Although the correlation between 45−OH YTX abundance and the speed of YTX depuration could not be confirmed, we noted the half-life of YTX was more than two-times longer in queen scallops, which contained 100% YTX, than in mussels. No other bivalve species were affected by YTXs.This is the first detailed evaluation of AZAs and YTXs occurrences and their profiles in shellfish from Great Britain over a period of multiple years.     

Trends in ixodid tick abundance and distribution in Great Britain

Abstract.  The popular, but rarely documented, view in Britain is that ticks have increased in distribution and abundance over recent years. To assess this, we gathered evidence for changes in tick distribution and abundance by distributing a survey questionnaire throughout Britain and by analysing trends in the prevalence of tick infestation on red grouse chicks Lagopus lagopus scoticus Latham (Galliformes: Tetranoidae), gathered over 19 years at three Scottish sites, and on deer (Cetartiodactyla: Cervidae) culled over 11 years on 26 Ministry of Defence (MoD) estates. Based on the survey, the current known distribution of Ixodes ricinus Linnaeus (Acari: Ixodidae) has expanded by 17% in comparison with the previously known distribution. The survey indicated that people perceive there to be more ticks today than in the past at 73% of locations throughout Britain. Reported increases in tick numbers coincided spatially with perceived increases in deer numbers. At locations where both tick and deer numbers were reported to have increased, these perceived changes occurred at similar times, raising the possibility of a causal link. At other locations, tick numbers were perceived to have increased despite reported declines in deer numbers. The perceptions revealed by the survey were corroborated by quantitative data from red grouse chicks and culled deer. Tick infestation prevalence increased over time on all grouse moors and 77% of MoD estates and decreased at six locations.     

The role of the Badger (Meles meles) in rabies epizootiology and the implications for Great Britain

The occurrence of a wildlife rabies epizootic in Britain remains a very unlikely event, but it is important to examine all the possible consequences of such an event. Here, I examine the possible role of the European Badger (Meles meles) in such an epizootic. The population density of Badgers in Britain is much higher than that in Europe, and appears to have increased substantially over the last decade or so. The population parameters and epizootiology of rabies in the Badger are reviewed in comparison with the Fox (Vulpes vulpes) and other species. Mustelids appear to be very susceptible to rabies, with the smaller mustelids becoming aggressive, although Badgers do not appear to show heightened aggression when infected. Badger populations on the continent become severely reduced when rabies arrives in the area, and circumstantial evidence strongly suggests that Badgers can easily transmit the virus. Preliminary models support the idea that the Badger could be a very significant secondary host, especially in the initial rabies outbreak. The population recovery rate of the Badger suggests that it is unlikely to become a primary host, although short‐term epizootics in the Badger population are likely. The potential for controlling rabies in the Badger is also examined.     

A mink-free GB: perspectives on eradicating American mink Neovison vison from Great Britain and its islands

This paper examines the case for, and plausibility of, eradicating American mink Neovison vison from mainland Great Britain and its associated offshore islands. This invasive species causes extensive damage to native fauna throughout Europe, and the UK Government is obliged to eradicate it, if feasible, under the Bern Convention. Current mink control buys time, but is patchy and dependent on substantial funding in perpetuity. If enacted, eradication would be cheaper in the long term and much more effective in preserving native wildlife. The methodology of an eradication campaign is explored, together with risks, challenges, and a tentative timeline and cost. We judge that mink eradication is now logistically feasible, due to technological developments and experience gained from landscape-scale control. Using live traps fitted with electronic sensors – ‘smart’ traps – as the primary means of catching mink would render the campaign efficient, humane and free of non-target mortality and negative environmental impacts. The ecological benefits of mink eradication would be profound, including greatly improving prospects for water vole Arvicola amphibius populations. Reinvasion is highly unlikely. The greatest logistical challenge is probably removing mink from Scottish west coast islands. Eradication might take around a decade and be dependent on co-ordination between many conservation, fishing, farming, and water-related organisations, together with the consent of landowners. By adding alarms to existing mink traps, land and water managers can pave the way to eradication now. A mink-free Great Britain would plausibly cost tens of millions of pounds, against which could be set the limitless future costs of mink control. Such a campaign would be by far the world's largest invasive predator eradication project by geographical area and would set a precedent for citizen-led conservation action globally. Regional trials would be extremely valuable in determining the costs and practicality of a GB-wide campaign.     

Distribution and current status of Sika Deer, Cervus nippon, in Great Britain

Introduced populations of Sika Deer are established in many parts of Britain and some, particularly in Scotland, are expanding their range rapidly. The taxonomy of Sika Deer and the timing and location of introductions is reviewed and current information on their range expansion and hybridization with Red Deer is provided. The current state of our knowledge of population parameters is insufficient to provide the basis for sound management in the future. The introduction of Sika Deer to Red Deer areas is considered to be irresponsible because of the likelihood of hybridization and the threat to the genetic integrity of Red Deer.     

The badger (Meles meles) in Britain: present status and future population changes

Over the past 150 years the badger is believed to have undergone major changes in status, and possibly also in distribution. In the last century persecution by gamekeepers in particular had an impact on badger numbers, especially in East Anglia. More recent changes in badger numbers and the need for a quantified base line survey against which to monitor future population changes provided the stimulus for a quantified national badger survey. This was achieved in the mid-1980s by a stratified survey in which pre-selected one kilometre squares used in the Institute of Terrestrial Ecology land classification system were surveyed for badgers. A total of 2455 squares (1.05%) of the land area of Britain) was surveyed, and this provided a means to (a) assess the current distribution and status of the badger, (b) assess the current levels of persecution of badgers and (c) monitor future badger population changes. Currently there are approximately 43 000 badger social groups in Britain. Sett blocking and badger digging were found to he widespread, and their effects on the badger population are discussed, as are the effects of the current TB control operations in south-west Britain. Future patterns of land use, particularly in response to changes in farming practice, could have significant effects on badger numbers. These are discussed in relation to potential changes in the Common Agricultural Policy. The effects of an expansion of forestry and the spread of urban areas on badger numbers are also estimated.     

Gyrodactylid developmental biology: historical review, current status and future trends

In the viviparous gyrodactylids, embryos develop one inside another within the parental uterus, a phenomenon with major implications for the biology of this species-rich group. Development occurs via two routes: first-born daughters develop at the centre of an embryo cluster in utero, whereas all other daughters develop from oocytes. The resulting offspring are, however, morphologically indistinguishable. We review here the history of gyrodactylid embryology in the context of current knowledge and, present additional cytogenetic and ultrastructural observations of embryonic development. These progenetic parasites are highly modified for viviparity; oocyte maturation and sperm storage occur in a single chamber, the Egg Cell Forming Region, and a mature oocyte passes into the uterus after the birth of the preceding, fully developed offspring. The uterus has a syncytial lining derived from anterior and posterior cap cells. These cells are the first to differentiate in the female reproductive system and may be involved in controlling development. Embryos receive nutrients via the uterus rather than from vitelline cells. Traditionally, development of the first-born daughter has been considered a form of polyembryony, although paedogenesis has also been suggested. In contrast to previous studies, we could not trace lineage of the first-born daughter to a single quiescent macromere. However, only mitotic divisions have been conclusively observed in the intraembryonic generation, indicating an asexual origin. All other daughters are formed from meiotically derived oocytes by sexual reproduction or automictic parthenogenesis. The latter may involve pre-meiotic doubling of chromosomes, but the precise mechanism and the relative proportion of sexual and parthenogenetic offspring are unknown. Exceptionally, cleavage in Gyrodactylus spp. occurs by duets rather than quartets (a pattern previously only recorded in acoels) and is characterised by extensive cell rearrangements. Blastomeres may be connected by fine cytoplasmic processes or completely disassociated and are readily redistributed by the muscular actions of the parental uterus. This process resembles 'Blastomeren-Anarchie' of rhabdocoels but without the structural support of vitelline cells. It prevents generation of early cell fate maps and indicates regulative, rather than mosaic, development. Structures such as the gut and excretory system differentiate late, and are highlighted, together with the attachment apparatus, as examples of post-embryonic differentiation. Molecular and cellular techniques are now essential to further elucidate mechanisms of gyrodactylid reproduction, which will in turn contribute to current debates with animal embryology.     

Integrating species and habitat data for nature conservation in Great Britain: data sources and methods

1. Britain is unusual in the quantity and quality of species and habitat data available, at both national and regional scales. This paper reviews the sources, coverage and quality of these data. 2. Habitat and species data are used by conservation agencies in England, Scotland and Wales for site selection and for monitoring habitat quality. The paper argues, however, that neither habitat data nor species distribution data on their own are sufficient to locate and monitor habitats for nature conservation purposes effectively. 3. Differences in sampling methodologies between habitat and species surveys present methodological difficulties for the development of an integrated monitoring system that uses both types of data. These problems need to be overcome if habitat and species data are to be used more effectively for nature conservation in the wider countryside. 4. A more integrated system based on the concept of biotope occupancy is proposed and discussed. The implementation of the system would assist with understanding those factors that explain observed patterns in species distribution and diversity, thereby helping to improve the effectiveness of policies for nature conservation.     

Changes in Biological Control Usage in Great Britain Between 1968 and 1995 with Particular Reference to Biological Control on Tomato Crops

This paper outlines the overall changes in the use of both conventional pesticides and biological control agents on all crops in Great Britain since 1968 and looks at usage within the tomato crop in particular. The total pesticide treated area, including repeat applications to the same crop, increased from 14 million ha in 1976 to 17 million ha in 1981 and almost doubled to over 28 million ha in 1985. In 1998, the total pesticide treated area stood at 46 million ha. Usage of insecticides followed the same pattern as that of total pesticides with increases in the use of pyrethroids and decreases in organochlorine, organophosphate and carbamates. Use of biological control agents increased from just 17 ha in 1968 to approximately 30 000 ha in 1999. Usage of biological control agents in 1995 constituted less than one percent of the total pesticide treated area. Up until 1981, only two biological control agents, Encarsia formosa and Phytoseiulus persimilis , were recorded. However, in 1995 the total number of parasites, predators and other biological control agents recorded was 23. Although both the area of tomatoes grown in Great Britain and the use of insecticides on tomatoes has significantly declined since 1968, the area treated with biological control agents continued to increase over the same period. In 1995, the biological control agent-treated area exceeded 10 000 ha and accounted for over 70% of the area of tomatoes treated.     

The ixodid tick species attaching to domestic dogs and cats in Great Britain and Ireland

The species of ixodid ticks, attached to dogs and cats presented to veterinary practices in Great Britain and Ireland were identified. Most host animals carried only one tick species with Ixodes ricinus Linné (Acari: Ixodidae) being the most common, identified on 52% of animals, Ixodes hexagonus Leach (Acari: Ixodidae) the second most common (on 39%) and Ixodes canisuga Johnston (Acari: Ixodidae) the third most common (on 11%). A significantly higher proportion of dogs than cats carried I. ricinus, while I. hexagonus was more frequently carried by cats. One animal carried a single specimen of Haemaphysalis punctata Canestrini & Fanzago (Acari: Ixodidae), one carried a Dermacentor reticulatus Fabricius (Acari: Ixodidae) but none carried Rhipicephalus sanguineus Latreille (Acari: Ixodidae). This indicates that the latter two species, vectors of 'exotic' tick-borne diseases, remain at low densities in Great Britain and Ireland. Retrospective information on exposure of the animals to different habitats and geographic regions was collected by questionnaire and subject to contingency table and logistic regression analysis. Woodlands and moorlands were habitats significantly associated with I. ricinus attachment. Exposure to urban parks was significantly associated with I. hexagonus attachment and exposure to boarding kennels and catteries was significantly associated with I. canisuga attachment. Ixodes hexagonus, rather than I. ricinus, was the ixodid tick species most likely to be encountered by urban populations of dogs and cats and, by inference, possibly also humans. The implications of these findings, for the transmission of tick-borne pathogens to dogs, cats and humans are discussed.     

Recent history,current status,conservation and management of native mammalian carnivore species in Great Britain

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Population status, trends and a re-examination of the hypotheses explaining the recent declines of the southern elephant seal Mirounga leonina

1. Between the 1950s and 1990s the southern elephant seal Mirounga leonina underwent large decreases in population size throughout most of its breeding range in the Southern Ocean. While current population estimates suggest a recent recovery, some breeding populations have continued to decrease in recent years (Macquarie and Marion Islands), others have either remained stable (South Georgia, Kerguelen and Heard Island) or have increased (Peninsula Valdés, Argentina). 2. Intrinsic hypotheses for patterns of regional decline include factors that are affected by density-dependent mechanisms: (i) paucity of males, (ii) population ‘overshoot’ and (iii) pandemic disease. Extrinsic hypotheses include (iv) predation, (v) competition with fisheries concerns, (vi) interspecific competition, (vii) environmental change and (viii) human disturbance. Of the eight hypotheses proposed and examined here, we conclude that three can be discounted (i, v, viii), three are unlikely, but may require more testing (ii, iii, iv) and two are plausible (vi, vii). 3. The interspecific competition hypothesis is difficult to test because it requires the simultaneous monitoring of species that overlap directly with elephant seals, many of which have not been identified or little is known. However, an analysis of the relationship between log variance and log abundance (Taylor's power law) for populations of southern and northern elephant seals suggests that interspecific competition is not a significant factor in the decline of the southern elephant seal. 4. The hypothesis that decreases in southern elephant seal populations between the 1950s and 1990s were caused by the environmental change is the easiest to test and most plausible of the hypotheses. We propose a framework by which to test this hypothesis to determine how food availability affects individual survival.