Estimating the movement among staging areas of the barnacle goose ( Branta leucopsis )

Barnacle geese ( Branta leucopsis ) make annual migrations between breeding colonies in northern Europe and Eurasia to wintering grounds in Holland. During the migration, they sojourn for several weeks in five areas on the northern coast of Germany. Observers traverse these areas during the course of studying the flocks. Previous belief was that there was little exchange of birds among the five areas; however, some banded birds were observed in more than one area indicating that some movement takes place. In this presentation, we estimate the movement rates among the areas using open- and closed-population models.     

Elephant-seal movements: Modelling migration

Elephant seals migrate over vast areas of the eastern North Pacific Ocean between rookeries in southern California and distant northern foraging areas. Several models of particle movement were evaluated and a model for great-circle motion found to give reasonable results for the movement of an adult female. This model takes specific account of the fact that the movement is on the surface of a sphere and that the animal is apparently heading toward a particular destination. The parameters of the motion were estimated. Such a great-circle path of migration may imply that these seals have the ability to assess their position with respect to some global or celestial cues, allowing them to continually adjust their course and achieve the most direct geodesic route between origin and destination of migration. But the navigational mechanism actually used by these seals to accomplish such feats is as yet unknown.     

Testing the effect of conspecific reproductive success on dispersal and recruitment decisions in a colonial bird: Design issues

Factors affecting dispersal and recruitment in animal populations will play a prominent role in the dynamics of populations. This is particularly the case for subdivided populations where the dispersal of individuals among patches may lead to local extinction and 'rescue effects'. A long-term observational study carried out in Brittany, France, and involving colour-ringed Black-legged Kittiwakes (Rissa tridactyla) suggested that the reproductive success of conspecifics (or some social correlate) could be one important factor likely to affect dispersal and recruitment. By dispersing from patches where the local reproductive success was low and recruiting to patches where the local reproductive success was high, individual birds could track spatio-temporal variations in the quality of breeding patches (the quality of breeding patches can be affected by different factors, such as food availability, the presence of predators or ectoparasites, which can vary in space and time at different scales). Such an observational study may nevertheless have confounded the role of conspecific reproductive success with the effect of a correlated factor (e.g. the local activities of a predator). In other words, individuals may have been influenced directly by the factor responsible for the low local reproductive success or indirectly by the low success of their neighbours. Thus, an experimental approach was needed to address this question. Estimates of demographic parameters (other than reproductive success) and studies of the response of marked individuals to changes in their environment usually face problems associated with variability in the probability of detecting individuals and with nonindependence among events occurring on a local scale. Further, very few studies on dispersal have attempted to address the causal nature of relationships by experimentally manipulating factors. Here we present an experiment designed to test for an effect of local reproductive success of conspecifics on behavioural decisions of individuals regarding dispersal and recruitment. The experiment was carried out on Kittiwakes within a large seabird colony in northern Norway. It involved (i) the colour banding of several hundreds of birds; (ii) the manipulation (increase/decrease) of the local reproductive success of breeding groups on cliffpatches; and (iii) the detailed survey of attendance and activities of birds on these patches. It also involved the manipulation of the nest content of marked individuals breeding within these patches (individuals failing at the egg stage were expected to respond in terms of dispersal to the success of their neighbours). This allowed us to test whether a lower local reproductive success would lower (1) the attendance of breeders at the end of the breeding season; (2) the presence of prospecting birds; and (3) the proportion of failed breeders that came back to breed on the same patch the year after. In this paper, we discuss how we dealt with (I) the use of return rates to infer differences in dispersal rates; (II) the trade-off between sample sizes and local treatment levels; and (III) potential differences in detection probabilities among locations. We also present some results to illustrate the design and implementation of the experiment.     

Transient animals in a resident population of snow geese: Local emigration or heterogeneity?

The estimation of survival rates from analysis of recapture of individually marked animals assumes that all individuals are equally likely to be re-encountered. This assumption is frequently violated in natural populations due to movements to and from the sampling area. We evaluated potential sources of heterogeneity using data from recaptures of 36000 individually marked female lesser snow geese, Anser c. caerulescens , from an expanding population in northern Manitoba, Canada. By stratifying individuals according to marking age and origin (hatched at the colony or not), we assessed the degree to which variation in apparent survival reflected permanent or temporary differences in emigration and effects of handling. In general, for birds ringed as adults, estimated apparent survival rates were significantly lower during the first year after ringing than in subsequent years. By comparing birds ringed as adults (classified by origin) with those ringed as goslings, we were able to demonstrate that these differences are not due to permanent emigration from the colony by transient individuals or heterogeneity of individual capture probability, but more likely reflect differences among individuals in their response to initial marking. Approximately 25% of birds permanently emigrate from the sampling area following marking.     

Transient animals in a resident population of snow geese: local emigration or heterogeneity?

The estimation of survival rates from analysis of recapture of individually marked animals assumes that all individuals are equally likely to be re-encountered. This assumption is frequently violated in natural populations due to movements to and from the sampling area. We evaluated potential sources of heterogeneity using data from recaptures of 36000 individually marked female lesser snow geese, Anser c. caerulescens , from an expanding population in northern Manitoba, Canada. By stratifying individuals according to marking age and origin (hatched at the colony or not), we assessed the degree to which variation in apparent survival reflected permanent or temporary differences in emigration and effects of handling. In general, for birds ringed as adults, estimated apparent survival rates were significantly lower during the first year after ringing than in subsequent years. By comparing birds ringed as adults (classified by origin) with those ringed as goslings, we were able to demonstrate that these differences are not due to permanent emigration from the colony by transient individuals or heterogeneity of individual capture probability, but more likely reflect differences among individuals in their response to initial marking. Approximately 25% of birds permanently emigrate from the sampling area following marking.     

Test for age-specificity in survival of the common tern

Much effort in life-history theory has been addressed to the dependence of life-history traits on age, especially the phenomenon of senescence and its evolution. Although senescent declines in survival are well documented in humans and in domestic and laboratory animals, evidence for their occurrence and importance in wild animal species remains limited and equivocal. Several recent papers have suggested that methodological issues may contribute to this problem, and have encouraged investigators to improve sampling designs and to analyse their data using recently developed approaches to modelling of capture-mark-recapture data. Here we report on a three-year, two-site, mark-recapture study of known-aged common terns (Sterna hirundo) in the north-eastern USA. The study was nested within a long-term ecological study in which large numbers of chicks had been banded in each year for > 25 years. We used a range of models to test the hypothesis of an influence of age on survival probability. We also tested for a possible influence of sex on survival. The cross-sectional design of the study (one year's parameter estimates) avoided the possible confounding of effects of age and time. The study was conducted at a time when one of the study sites was being colonized and numbers were increasing rapidly. We detected two-way movements between the sites and estimated movement probabilities in the year for which they could be modelled. We also obtained limited data on emigration from our study area to more distant sites. We found no evidence that survival depended on either sex or age, except that survival was lower among the youngest birds (ages 2-3 years). Despite the large number of birds included in the study (1599 known-aged birds, 2367 total), confidence limits on estimates of survival probability were wide, especially for the oldest age-classes, so that a slight decline in survival late in life could not have been detected. In addition, the cross-sectional design of this study meant that a decline in survival probability within individuals (actuarial senescence) could have been masked by heterogeneity in survival probability among individuals (mortality selection). This emphasizes the need for the development of modelling tools permitting separation of these two phenomena, valid under field conditions in which the recapture probabilities are less than one.     

Asymmetric exchange between populations differing in habitat quality: A metapopulation study on the citril finch

The citril finch ( Serinus citrinella ) is a Cardueline finch restricted to the high mountains of western Europe. Since 1991 we have captured-recaptured about 6000 birds in two contrasting subpopulations located on the same mountain but separated by 5 km in distance. Citril finches, at the north-facing locality (La Vansa), rely more on Pine trees ( Pinus uncinata ) as their main food source, than birds at the south-facing locality (La Bofia), which rely more on herb seeds, which are of lower energetic content. Birds at La Vansa had higher body mass and fat score than those at La Bofia, suggesting that La Vansa was a site of higher-quality than La Bofia. By the use of a metapopulation approach and multistate models, we found that citril finches at the high-quality locality (La Vansa) showed higher survival rates than those at the low-quality one (La Bofia) (Vansa adults: φ = 0.42 - 0.04, juveniles: φ = 0.34 - 0.05; Bofia adults: φ = 0.35 - 0.04, juveniles: φ = 0.28 - 0.05). Dispersal was also asymmetric and higher for juvenile birds, with movement rates for juvenile citril finches from the low-quality to the higher-quality locality (Bofia to Vansa: é = 0.38 - 0.10) higher than the reverse (Vansa to Bofia: é = 0.09 - 0.03). We also investigated time-specific factors (e.g. meteorological data and fructification rate of Pinus ) as potential predictors of overall mortality and dispersal patterns. The results do not allow strong conclusions regarding the impact of these factors on survival and movement rates. Patterns of movement found in the Citril Finch between localities document a new model for the dispersal of species from low to high quality habitats, which we label of 'sources and pools'. This contrasts with currently accepted models of 'sources and sinks', in which movement is from high to low quality habitats, and 'Ideal Free Distributions', in which there is a balanced dispersal between habitats of different quality.     

Uses of ringing data for the conservation and management of bird populations: A ringing scheme perspective

This review considers current and potential uses of ring-recovery and mark-recapture methods for conservation-oriented research by European ringing schemes. These schemes are concerned mainly with large-scale studies of the demography and movements of widespread species, much of the data being gathered by volunteers. The data holdings and data-gathering potential of the 33 European ringing schemes are outlined. Over 110 million birds have been ringed in Europe giving rise to 1.8 million recoveries. Some 64% of these recoveries are held in the computerized EURING data bank. Passerines comprise 43% of all recoveries and only 15% are of waterfowl. Currently, about 4 million birds are ringed each year and 90 000 recoveries are reported. Ringing effort is much higher in northern and western Europe than in southern and eastern Europe. Most schemes have recorded the ringing and recovery details of birds that have been recovered in computer files but most ringing data are held only on paper. These ringing data must be computerized for rigorous analyses of survival or movements. Without such computerization, future widespread ringing will be of little value. Five key areas of conservation-oriented research using data from European ringing schemes are identified; monitoring, investigating the causes of population declines, impacts of hunting, flyway networks and seabird studies. Current work and future research opportunities in these areas are discussed, and conservation priorities are identified. Demographic studies for monitoring and identifying the causes of declines are developing well, and are likely to be enhanced further by more gathering of mark-recapture data from standardized projects (such as constant effort sites), by improved access to computerized ringing data and by the development of more flexible, user-friendly software for ring-recovery analysis. Interest in studies of movements is reviving, with quantitative methods starting to be applied to population turnover at migratory stop-over sites (Jolly-Seber models) and to movements between sites (multi-state models). Future planned ringing studies will be important for testing ideas about the dynamics of meta-populations. European ringing schemes have the opportunity to enhance greatly their contribution to conservation over the next decade. This will require better access to computerized data and the development of more planned, cooperative projects at European and national scales. The close collaboration of biologists and statisticians in the analysis of previously collected data should be extended to the review of existing sampling strategies and to the development of new projects.     

Separation of survival and movement rates in multi-state tag-return and capture-recapture models

There has been growing interest in the estimation of transition probabilities among stages (Hestbeck et al. , 1991; Brownie et al. , 1993; Schwarz et al. , 1993) in tag-return and capture-recapture models. This has been driven by the increasing interest in meta-population models in ecology and the need for parameter estimates to use in these models. These transition probabilities are composed of survival and movement rates, which can only be estimated separately when an additional assumption is made (Brownie et al. , 1993). Brownie et al. (1993) assumed that movement occurs at the end of the interval between time i and i + 1. We generalize this work to allow different movement patterns in the interval for multiple tag-recovery and capture-recapture experiments. The time of movement is a random variable with a known distribution. The model formulations can be viewed as matrix extensions to the model formulations of single open population capturerecapture and tag-recovery experiments (Jolly, 1965; Seber, 1965; Brownie et al. , 1985). We also present the results of a small simulation study for the tag-return model when movement time follows a beta distribution, and later another simulation study for the capture-recapture model when movement time follows a uniform distribution. The simulation studies use a modified program SURVIV (White, 1983). The Relative Standard Errors (RSEs) of estimates according to high and low movement rates are presented. We show there are strong correlations between movement and survival estimates in the case that the movement rate is high. We also show that estimators of movement rates to different areas and estimators of survival rates in different areas have substantial correlations.     

Estimating survival rates from recoveries of birds ringed as young: A case study

Models for analysis of survival rates from recoveries of birds ringed as young were evaluated for lesser snow geese ringed on the breeding grounds at La Perouse Bay, Manitoba from 1970 to 1992. Analyses of birds ringed as adults and young indicate recovery rates were lower for young than for older birds and varied independently in the two age classes. Adult survival increased over the study, while that of immatures decreased. Using only recoveries of birds ringed as young, models incorporating observed variation in recovery rates were not identifiable. Many sets of constraints could be selected to make the model identifiable, but there was no objective way to distinguish among them, and each could lead to different conclusions. The observed changes in survival rates could not be estimated. Previous analyses have shown that models for birds ringed as young can be used to test even complex variation in survival rates, provided that recovery rates do not vary with age. Unfortunately, as shown by the geese, this assumption may often be violated and can only be tested with additional data, preferably from birds recaptured or ringed as sub-adults or adults.     

Estimating survival rates from recoveries of birds ringed as young: a case study

Models for analysis of survival rates from recoveries of birds ringed as young were evaluated for lesser snow geese ringed on the breeding grounds at La Perouse Bay, Manitoba from 1970 to 1992. Analyses of birds ringed as adults and young indicate recovery rates were lower for young than for older birds and varied independently in the two age classes. Adult survival increased over the study, while that of immatures decreased. Using only recoveries of birds ringed as young, models incorporating observed variation in recovery rates were not identifiable. Many sets of constraints could be selected to make the model identifiable, but there was no objective way to distinguish among them, and each could lead to different conclusions. The observed changes in survival rates could not be estimated. Previous analyses have shown that models for birds ringed as young can be used to test even complex variation in survival rates, provided that recovery rates do not vary with age. Unfortunately, as shown by the geese, this assumption may often be violated and can only be tested with additional data, preferably from birds recaptured or ringed as sub-adults or adults.     

中国各地区医疗卫生服务的生产效率分析

医疗卫生是与国民密切相关的一个问题,所以医疗卫生服务的生产效率如何倍受人们的关注。运用DEA模型可以对中国各地区的医疗卫生服务生产效率进行研究,分析不同地区效率高低的原因。结果显示,虽然总体上中国的医疗卫生服务的生产效率处于一个较低水平,但地区之间还是存在着很大的区别,并且地区间即便都是高效率或者低效率的地区,其投入和产出水平也不尽相同。     

中国城市经济可持续发展的新视角——基于STATA面板数据分析

本文运用多元统计综合评价的方法,计算出2003至2007年间中国286个地级市的城市“紧凑度”以及经济可持续发展的综合得分。将全部城市划分为8大经济区域后,针对不同区域选择不同的模型,进行面板数据分析,检验结果表明：北部沿海地区、东部沿海地区、南部沿海地区适合发展紧凑型城市,这些地区城市“紧凑度”越高,将越有利于经济的可持续发展;而其他地区现阶段暂不适合发展紧凑型城市。     

Statistical modelling of individual animal movement: an overview of key methods and a discussion of practical challenges

With the influx of complex and detailed tracking data gathered from electronic tracking devices, the analysis of animal movement data has recently emerged as a cottage industry among biostatisticians. New approaches of ever greater complexity are continue to be added to the literature. In this paper, we review what we believe to be some of the most popular and most useful classes of statistical models used to analyse individual animal movement data. Specifically, we consider discrete-time hidden Markov models, more general state-space models and diffusion processes. We argue that these models should be core components in the toolbox for quantitative researchers working on stochastic modelling of individual animal movement. The paper concludes by offering some general observations on the direction of statistical analysis of animal movement. There is a trend in movement ecology towards what are arguably overly complex modelling approaches which are inaccessible to ecologists, unwieldy with large data sets or not based on mainstream statistical practice. Additionally, some analysis methods developed within the ecological community ignore fundamental properties of movement data, potentially leading to misleading conclusions about animal movement. Corresponding approaches, e.g. based on Lévy walk-type models, continue to be popular despite having been largely discredited. We contend that there is a need for an appropriate balance between the extremes of either being overly complex or being overly simplistic, whereby the discipline relies on models of intermediate complexity that are usable by general ecologists, but grounded in well-developed statistical practice and efficient to fit to large data sets.     

Correspondence Analysis and Its Application in Oncology

To explore the application value of correspondence analysis in oncology, we adopted correspondence analysis method to analyze the relationship between the amount of food eaten in some cities in China and the male gastric carcinoma mortality. According to scatter plots of row and column points, there are regional differences among the male gastric carcinoma mortality in different cities of China. Southern male citizens ate more rice and salt, less wheaten food, and fewer light vegetables than northern ones. There may be some carcinogenic factors in some food.     

An intelligent system for experimental design-some ideas

There is a growing movement towards the construction of statistical expert systems by statisticians to assist incertain aspects of their work. As one of the most'abused’ areas, experimental design could benefit from a system ofthis type. This paperoutlines some ideas on how a system for intelligently constructing designs could be built.     

Comparison of survival estimates obtained from three different methods of recapture in the same population of the great tit

Recaptures of marked birds can be used to estimate their survival. We suspect that the various methods of capture might not be equally suited for this purpose. In the long-term study of the great tit at our institute, recaptures were routinely made in three different ways: capture of parents feeding their young at the nest; capture of birds roosting in nest-boxes; mist-netting. We analyzed 20 years of captures from the study site at the Hoge Veluwe to obtain estimates of adult survival and capture rates from captures obtained by each method. The three sets of estimates differ and our analyses suggest that the best method was the capture of breeding birds, while mist-netting was the least suitable.     

浙江要素市场分析与研究

摘　　要:本文以浙江要素市场为研究对象,针对浙江经济发展的特点,在运用大量数据进行实证分析的基础上,揭示了劳动力、资本、土地、技术、中介组织等生产要素的内在联系和对经济增长的贡献,并据此对要素市场的流动规律和本质特性进行理论上的探索,论证要素市场在资源配置中的基础性作用。试图明晰浙江要素市场发展的轨迹,并对此进行评述,提出了进一步发展浙江要素市场的政策措施和改革思路,进而探索浙江经济增长的规律,寻找浙江经济可持续增长的有效路径     

A micro analysis of the macro differences in refusal risk among metropolitan areas. The case of the Italian multipurpose survey

Although still modest, non response rates in multipurpose household surveys have recently increased, especially in some metropolitan areas. Previous analyses have shown that refusal risk depends on the interviewers' characteristics. The aim of this paper is to explain the difference in refusal risk among metropolitan areas by analysing the strategies adopted in the recruitment of interviewers through a multilevel approach. The Annual Survey on Living conditions is a PAPI survey of the "Multipurpose" integrated system of social surveys and it represents our data base. For non responding household, data on non response by reason, municipality and characteristics of the interviewer are available. The results highlight that those cities recruiting interviewers mainly among young students have a higher refusal risk. These results are particularly important as they indicate that recruitment strategies may have a substantial impact on non sampling errors. Acknowledgements An earlier version of this article was presented at the International Conference on Improving Survey, University of Copenhagen, Denmark, August 25-28, 2002. We would like to thank the participants to the presentation for their useful comments and suggestions. Opinions expressed are those of the authors and do not necessarily represent the official position of any of the institutions they work for.     

Difficulties in the use of auxiliary variables in Markov chain Monte Carlo methods

Markov chain Monte Carlo (MCMC) methods are now widely used in a diverse range of application areas to tackle previously intractable problems. Difficult questions remain, however, in designing MCMC samplers for problems exhibiting severe multimodality where standard methods may exhibit prohibitively slow movement around the state space. Auxiliary variable methods, sometimes together with multigrid ideas, have been proposed as one possible way forward. Initial disappointing experiments have led to data-driven modifications of the methods. In this paper, these suggestions are investigated for lattice data such as is found in imaging and some spatial applications. The results suggest that adapting the auxiliary variables to the specific application is beneficial. However the form of adaptation needed and the extent of the resulting benefits are not always clear-cut.