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William A. Link 

USGS Patuxent Wildlife Research Center 
12100 Beech Forest Road 
Laurel, MD 20708-4017

Photo of William A. Link

Telephone: 301-497-5631

Fax: 301-497-5455

Email: wlink@usgs.gov

Mathematical Statistician 

Primary Responsibilities: 
Mathematical Statistician, Biometrics Group, 1987-Present.  
Duties include development of mathematical models and analytical tools for investigation of ecological questions and for monitoring of wildlife populations, serves as consultant to quantitative ecologists and biologists. Current research includes application of Bayesian methods to hierarchical models. 

Education/Training: 
University of Massachusetts at Amherst 
M.A., Ph.D., Mathematical Statistics, 1983, 1986. 
Dissertation: Contributions to Reliability Theory and Survival Analysis 
Western Maryland College, B.A., Mathematics 1980.

Areas of Expertise/Interest: Statistics, Bayesian analysis 

Active Projects:
Statistical methods for count survey data 
Development of new statistical methods for biological applications 

Publications:

Link book cover

Link, W. A. and R. J. Barker. 2010. Bayesian Inference: with ecological applications. Elsevier/Academic , Boston, MA. xiii, 339 pp. book info

Link, W. A., J. Yoshizaki, L. L. Bailey, and K. H. Pollock. 2010. Uncovering a latent multinomial: Analysis of mark-recapture data with misidentification. Biometrics 66(1):178-185. abstract

Droege, S., V. J. Tepedino, G. Lebuhn, W. A. Link, R. L. Minckley, Q. Chen, and C. Conrad. 2010. Spatial patterns of bee captures in North American bowl trapping surveys. Insect Conservation and Diversity 3(1):15-23. abstract

Nichols, J. M., M. Currie, F. Bucholtz, and W. A. Link, . 2010. Bayesian estimation of weak material dispersion: theory and experiment. Optics Express 18(3):2076-2089. abstract

Nichols, J. M., W. A. Link, K. D. Murphy, and C. C. Olson. 2010. A Bayesian approach to identifying structural nonlinearity using free-decay response: Application to damage detection in composites. Journal of Sound and Vibration 329(15):2995-3007. abstract

Link, W. A. and R. J. Barker. 2009. Bayes factors and multimodel inference. Pages 595-615 in David L. Thomson, Evan G. Cooch, and Michael J. Conroy, editors. Modeling demographic processes in marked populations. Environmental and ecological statistics 3. Springer, New York and London. xxiv, 1136 pp. book info

Rotella, J. J., W. A. Link, J. D. Nichols, G. L. Hadley, R. A. Garrott, and K. M. Proffitt. 2009. An evaluation of density-dependent and density-independent influences on population growth rates in Weddell seals. Ecology 90(4):975-984. abstract

Seavy, N. E., M. H. Reynolds, W. A. Link, and J. S. Hatfield. 2009. Postcatastrophe population dynamics and density dependence of an endemic island duck. Journal of Wildlife Management 73(3):414-418. BioOne JWM

Yoshizaki, J., C. Brownie, K. H. Pollock, and W. A. Link. 2009. Modeling misidentification errors that result from use of genetic tags in capture-recapture studies. Environmental and Ecological Statistics online July 23 abstract

Link, W. A. and R. J. Barker. 2008. Efficient implementation of the Metropolis-Hastings algorithm, with application to the Cormack–Jolly–Seber model. Environmental and Ecological Statistics 15:79-87. abstract

Link, W. A., J. R. Sauer, and D. K. Niven. 2008. Combining Breeding Bird Survey and Christmas Bird Count data to evaluate seasonal components of population change in Northern Bobwhite. Journal of Wildlife Management 72(1):44-51. BioOne JWM

Rattner, B. A., M. A. Whitehead, G. Gasper, C. U. Meteyer, W. A. Link, M. A. Taggart, A. A. Meharg, O. H. Pattee, and D. J. Pain. 2008. Apparent tolerance of turkey vultures (Cathartes aura) to the non-steroidal anti-inflammatory drug diclofenac. Environmental Toxicology and Chemistry 27(11):2341-2345. abstract

Sauer, J. R., W. A. Link, W. L. Kendall, J. R. Kelley, and D. K. Niven. 2008. A hierarchical model for estimating change in American Woodcock populations. Journal of Wildlife Management 72(1):204-214. BioOne JWM

Albers, P. H., M. T. Koterba, R. Rossmann, W. A. Link, J. B. French, R. S. Bennett, and W. C. Bauer. 2007. Effects of methylmercury on reproduction in American kestrels. Environmental Toxicology and Chemistry 26(9):1856-1866. abstract

Haramis, G. M., W. A. Link, P. C. Osenton, D. B. Carter, R. G. Weber, N. A. Clark, M. A. Teece, and D. S. Mizrahi. 2007. Stable isotope and pen feeding trial studies confirm the value of horseshoe crab Limulus polyphemus eggs to spring migrant shorebirds in Delaware Bay. Journal of Avian Biology 38(3):367-376. abstract

Link, W. A. and P. H. Albers. 2007. Bayesian multimodel inference for dose-response studies. Environmental Toxicology and Chemistry 26(9):1867-1872. abstract

Link, W. A. and J. R. Sauer. 2007. Seasonal components of avian population change: Joint analysis of two large-scale monitoring programs. Ecology 88(1):49-55. abstract

Royle, J. A., R. M. Dorazio, and W. A. Link. 2007. Analysis of multinomial models with unknown index using data augmentation. Journal of Computational and Graphical Statistics 16(1):67-85. abstract

Link, W. A. 2006. On identifiability in capture-recapture models - Reply. Biometrics 62(3):936-939. abstract

Link, W. A. and R. J. Barker. 2006. Model weights and the foundations of multimodel inference. Ecology 87(10):2626-2635. abstract

Link, W. A., J. R. Sauer, and D. K. Niven. 2006. A hierarchical model for regional analysis of population change using Christmas Bird Count data, with application to the American Black Duck. Condor 108(1):13-24. abstract

Rattner, B. A., M. A. McKernan, K. M. Eisenreich, W. A. Link, G. H. Olsen, D. J. Hoffman, K. A. Knowles, and P. C. McGowan. 2006. Toxicity and hazard of vanadium to mallard ducks (Anas platyrhynchos) and Canada geese (Branta canadensis). Journal of Toxicology and Environmental Health, Part A, 69(4):331-351. abstract

Royle, J. A. and W. A. Link. 2006. Generalized site occupancy models allowing for false positive and false negative errors. Ecology 87(4):835-841. abstract

Forsyth, D. M., W. A. Link, R. Webster, G. Nugent, and B. Warburton. 2005. Nonlinearity and seasonal bias in an index of brushtail possum abundance. Journal of Wildlife Management 69(3):976-984. BioOne JSTOR

Link, W. A. and R. J. Barker. 2005. Modeling association among demographic parameters in analysis of open population capture–recapture data. Biometrics 61(1):46-54. abstract

Royle, J. A. and W. A. Link. 2005. A general class of multinomial mixture models for anuran calling survey data. Ecology 86(9):2505-2512. abstract

Sauer, J. R., W. A. Link, J. D. Nichols, and J. A. Royle. 2005. Using the North American Breeding Bird Survey as a tool for conservation: A critique of Bart et al. (2004). Journal of Wildlife Management 69(4):1321-1326. BioOne JSTOR

Sauer, J. R., W. A. Link, and J. A. Royle. 2005. Hierarchical models and Bayesian analysis of bird survey information. Pages 762-770 (v. 2) in C. John Ralph and Terrell D. Rich, editors. Bird Conservation Implementation and Integration in the Americas: Proceedings of the Third International Partners in Flight Conference 2002. General Technical Report PSW-191. U. S. Forest Service, Pacific Southwest Research Station, Albany, California. 2 volumes: xiv, 1296 pp. PDF

Unwin, M. J., M. Webb, R. J. Barker, and W. A. Link. 2005. Quantifying production of salmon fry in an unscreened irrigation system: A case study on the Rangitata River, New Zealand. North American Journal of Fisheries Management 25(2):619-634. abstract

Doherty, P. F., Jr., E. A. Schreiber, J. D. Nichols, J. E. Hines, W. A. Link, G. A. Schenk, and R. W. Schreiber. 2004. Testing life history predictions in a long-lived seabird: a population matrix approach with improved parameter estimation. Oikos 105(3):606-618. abstract

Karanth, K. U., J. D. Nichols, N. S. Kumar, W. A. Link, and J. E. Hines. 2004. Tigers and their prey: Predicting carnivore densities from prey abundance. Proceedings of the National Academy of Sciences of the USA 101(14):4854-4858. abstract

Link, W. A. 2004. Individual heterogeneity and identifiability in capture–recapture models. Pages 87-91 in Joan Carles Senar, André Dhondt, and Michael J. Conroy, Executive editors. Actes del Congrès Internacional EURING 2003, Alemanya /Actas del Congreso Internacional EURING 2003, Alemania /Proceedings of the International Conference EURING 2003, Deutschland. Animal Biodiversity and Conservation 27(1). PDF

Link, W. A. 2004. Whole-ecosystem experiments: replication and arguing from error: commentary. Pages 248-256 in Mark L. Taper and Subhash R. Lele, editors. The nature of scientific evidence: statistical, philosophical, and empirical considerations. University of Chicago Press, Chicago. xviii, 567 pp. contents

Link, W. A. and R. J. Barker. 2004. Hierarchial mark–recapture models: a framework for inference about demographic processes. Pages 441-449 in Joan Carles Senar, André Dhondt, and Michael J. Conroy, Executive editors. Actes del Congrès Internacional EURING 2003, Alemanya /Actas del Congreso Internacional EURING 2003, Alemania /Proceedings of the International Conference EURING 2003, Deutschland. Animal Biodiversity and Conservation 27(1). PDF

Niven, D. K., J. R. Sauer, G. S. Butcher, and W. A. Link. 2004. Christmas Bird Count provides insights into population change in land birds that breed in the boreal forest. American Birds 58(104th Christmas Bird Count):10-20. PDF

Sauer, J. R. and W. A. Link. 2004. Some consequences of using counts of birds banded as indices to populations. Pages 168-172 in C. John Ralph and E. H. Dunn, editors. Monitoring bird populations with mist nets. Studies in Avian Biology 29. 211 pp.

Sauer, J. R., W. A. Link, and D. K. Niven. 2004. Statistical analyses make the Christmas Bird Count relevant for conservation. American Birds 58(104th Christmas Bird Count):21-25. PDF

Sauer, J. R., W. A. Link, and J. A. Royle. 2004. Estimating population trends with a linear model: technical comments. Condor 106(2):435-440. BioOne JSTOR

Link, W. A. 2003. Nonidentifiability of population size from capture-recapture data with heterogeneous detection probabilities. Biometrics 59(4):1123-1130. abstract

Link, W. A., J. A. Royle, and J. S. Hatfield. 2003. Demographic analysis from summaries of an age-structured population. Biometrics 59(4):778. abstract

Sauer, J. R. and W. A. Link. 2003. Hierarchical models and the analysis of bird survey information. Ornis Hungarica 12-13(1-2):217-222. PDF

Sauer, J. R., W. A. Link, and J. D. Nichols. 2003. Estimation of change in populations and communities from monitoring survey data. Pages 227-253 in David E. Busch and Joel C. Trexler, editors. Monitoring ecosystems: interdisciplinary approaches for evaluating ecoregional initiatives. Island Press, Washington, DC. xix, 447 pp. book info

Cam, E., W. A. Link, E. G. Cooch, J.-Y. Monnat, and E. Danchin. 2002. Individual covariation in life-history traits: seeing the trees despite the forest. American Naturalist 159(1):96-105. JSTOR

Cooch, E. G., E. Cam, and W. A. Link. 2002. Occam's shadow: levels of analysis in evolutionary ecology - where to next? Pages 19-48 in Byron J. T. Morgan and David L. Thomson, guest editors. Statistical analysis of data from marked bird populations. Journal of Applied Statistics 29(1-4). 669 pp. abstract

Link, W. A., E. Cam, J. D. Nichols, and E. G. Cooch. 2002. Of bugs and birds: Markov Chain Monte Carlo for hierarchical modeling in wildlife research. Journal of Wildlife Management 66(2):277-291. JSTOR

Link, W. A., E. G. Cooch, and E. Cam. 2002. Model-based estimation of individual fitness. Pages 207-224 in Byron J. T. Morgan and David L. Thomson, guest editors. Statistical analysis of data from marked bird populations. Journal of Applied Statistics 29(1-4). 669 pp. abstract

Link, W. A. and P. F. Doherty, Jr. 2002. Scaling in sensitivity analysis. Ecology 83(12):3299-3305. abstract

Link, W. A. and J. R. Sauer. 2002. A hierarchical analysis of population change with application to Cerulean Warblers. Ecology 83(10):2832-2840. abstract

Royle, J. A. and W. A. Link. 2002. Random effects and shrinkage estimation in capture-recapture models. Pages 329-351 in Byron J. T. Morgan and David L. Thomson, guest editors. Statistical analysis of data from marked bird populations. Journal of Applied Statistics 29(1-4). 669 pp. abstract

Royle, J. A., W. A. Link, and J. R. Sauer. 2002. Statistical mapping of count survey data. Pages 625-638 in J. Michael Scott, Patricia J. Heglund, Michael L. Morrison, Jonathan B. Haufler, and William A. Wall, editors. Predicting species occurrences : issues of accuracy and scale. Island Press, Washington, DC. xvii, 868 pp. book info

Sauer, J. R. and W. A. Link. 2002. Hierarchical modeling of population stability and species group attributes from survey data. Ecology 83(6):1743-1751. abstract

Sauer, J. R. and W. A. Link. 2002. Using Christmas Bird Count data in analysis of population change. American Birds (102nd Christmas Bird Count):10-14. PDF

Anderson, D. R., W. A. Link, D. H. Johnson, and K. P. Burnham. 2001. Suggestions for presenting the results of data analyses. Journal of Wildlife Management 65(3):373-378. JSTOR

Bennetts, R. E., W. A. Link, J. R. Sauer, and P. W. Sykes, Jr. 1999. Factors influencing counts in an annual survey of Snail Kites in Florida. Auk 116(2):316-323. PDF

Cooch, E. G. and W. A. Link. 1999. Estimating transition probabilities in unmarked populations --entropy revisited. Pages S55-61 in S. R. Baillie and P. M. North, editors. Large-scale Studies of Marked Birds, Proceedings of EURING 97 Conference. Bird Study 46(supplement). abstract

Link, W. A. 1999. Modeling pattern in collections of parameters. Journal of Wildlife Management 63(3):1017-1027. JSTOR

Link, W. A. and J. R. Sauer. 1999. Controlling for varying effort in count surveys --an analysis of Christmas Bird Count Data. Journal of Agricultural, Biological & Environmental Statistics 4(2):116-125. JSTOR

Link, W. A. and J. R. Sauer. 1999. On the importance of controlling for effort in analysis of count survey data: Modeling population change from Christmas Bird Count data. Pages 119-124 in Andreas J. Helbig and Martin Flade, editors. Bird numbers 1998: where monitoring and ecological research meet: proceedings of the 14th International Conference of the European Bird Census Council (EBCC) in Cottbus (Brandenburg), Germany, 23-31 March 1998. Vogelwelt 120 Suppl. AULU-Verlag, Wiebelsheim, Germany. 402 pp. Conf. info

Nisbet, I. C. T., J. S. Hatfield, W. A. Link, and J. A. Spendelow. 1999. Predicting chick survival and productivity of Roseate Terns from data on early growth. Waterbirds 22(1):90-97. JSTOR

Sauer, J. R. and W. A. Link. 1999. Regional analysis of population trajectories from the North American Breeding Bird Survey. Pages 31-38 in Andreas J. Helbig and Martin Flade, editors. Bird numbers 1998: where monitoring and ecological research meet: proceedings of the 14th International Conference of the European Bird Census Council (EBCC) in Cottbus (Brandenburg), Germany, 23-31 March 1998. Vogelwelt 120 Suppl. AULU-Verlag, Wiebelsheim, Germany. 402 pp. Conf. info

Link, W. A. 1998. Unbiasedness. Pages 4648-4650 in Peter Armitage and Theodore Colton, editors. Encyclopedia of Biostatistics, v. 6. John Wiley and Sons, Chichester, U.K. 6 volumes. lxii, 4898 pp.
republished as:
      Link, W. A.  2005.  Unbiasedness.  Pages 5603-5605 in Peter Armitage and Theodore Colton, editors.  Encyclopedia of Biostatistics, v. 8.  John Wiley, Hoboken, NJ.  .
      Link, W. A.  2002.  Unbiasedness.  Pages 767-769 in Robert C. Elston, Jane M. Olson, and Lyle Palmer, editors.  Biostatistical Genetics and Genetic Epidemiology. Wiley, New York.  xxiv, 831 pp.

Link, W. A. and J. R. Sauer. 1998. Estimating population change from count data: application to the North American Breeding Bird Survey. Ecological Applications 8(2):258-268. JSTOR ESA

Link, W. A. and J. R. Sauer. 1998. Estimating relative abundance from count data. Austrian Journal of Statistics 27(1 & 2):83-97. contents

Link, W. A. and J. R. Sauer. 1997. Estimation of population trajectories from count data. Biometrics 53(2):488-497. JSTOR

Link, W. A. and J. R. Sauer. 1997. New approaches to the analysis of population trends in land birds: Comment. Ecology 78(8):2632-2634. JSTOR ESA

Hatfield, J. S., W. A. Link, D. K. Dawson, and E. L. Lindquist. 1996. Coexistence and community structure of tropical trees in a Hawaiian montane rain forest. Biotropica 28(4B):746-758. JSTOR

Link, W. A. and D. C. Hahn. 1996. Empirical Bayes estimation of proportions with application to cowbird parasitism rates. Ecology 77(8):2528-2537. JSTOR

Link, W. A., E. F. Hill, J. E. Hines, and P. F. P. Henry. 1996. A resource conservative procedure for comparison of dose-response relationships. Environmental Toxicology and Chemistry 15(9):1612-1617. abstract

Link, W. A. and J. R. Sauer. 1996. Extremes in ecology: Avoiding the misleading effects of sampling variation in summary analyses. Ecology 77(5):1633-1640. JSTOR

Peterjohn, B. G., J. R. Sauer, and W. A. Link. 1995-1996. The 1994 and 1995 summary of the North American Breeding Bird Survey. Bird Populations 3:48-66.

Link, W. A. and J. R. Sauer. 1995. Estimation and confidence intervals for empirical mixing distributions. Biometrics 51(3):810-821. JSTOR

Haramis, G. M., E. L. Derleth, and W. A. Link. 1994. Flock sizes and sex ratios of canvasbacks in Chesapeake Bay and North Carolina. Journal of Wildlife Management 58(1):123-131. JSTOR

Link, W. A. and R. J. Barker. 1994. Density estimation using the trapping web design: A geometric analysis. Biometrics 50(3):733-745. JSTOR

Link, W. A., R. J. Barker, J. R. Sauer, and S. Droege. 1994. Within-site variability in surveys of wildlife populations. Ecology 75(4):1097-1108. JSTOR

Link, W. A. and K. U. Karanth. 1994. Correcting for overdispersion in tests of prey selectivity. Ecology 75(8):2456-2459. JSTOR

Link, W. A. and J. D. Nichols. 1994. On the importance of sampling variance to investigations of temporal variation in animal population size. Oikos 69(3):539-543. JSTOR

Link, W. A. and J. R. Sauer. 1994. Estimating equations estimates of trends. Bird Populations 2:23-32.

Nichols, J. D., J. E. Hines, K. H. Pollock, R. L. Hinz, and W. A. Link. 1994. Estimating breeding proportions and testing hypotheses about costs of reproduction with capture-recapture data. Ecology 75(7):2052-2065. JSTOR

Peterjohn, B. G., J. R. Sauer, and W. A. Link. 1994. The 1992 and 1993 summary of the North American Breeding Bird Survey. Bird Populations 2:46-61.

Sauer, J. R., B. G. Peterjohn, and W. A. Link. 1994. Observer differences in the North American Breeding Bird Survey. Auk 111(1):50-62. PDF

Barker, R. J., J. R. Sauer, and W. A. Link. 1993. Optimal allocation of point-count sampling effort. Auk 110(4):752-758. PDF

Link, W. A. 1993. Efficiency and optimal allocation in the staggered entry design. Communications in Statistics--Theory and Methods 22(2):485-503. abstract

Link, W. A. 1993. Simulation testing of unbiasedness of variance estimators. American Statistician 47(2):132-134. JSTOR

Erwin, R. M., J. S. Hatfield, and W. A. Link. 1991. Social foraging and feeding environment of the black-crowned night heron in an industrialized estuary . Bird Behaviour 9(1-2):94-102.

Link, W. A. and B. A. Hoover. 1991. The detection of density-dependence from a series of annual censuses--a comment. Ecology 72(4):1514-1515. JSTOR

Krementz, D. G., R. J. Barker, W. A. Link, J. E. Hines, P. O. Corr, and R. B. Owen. 1990. Response to Dufour and Ankney. Ornis Scandinavica 21(4):301-303. JSTOR

Link, W. A. and J. S. Hatfield. 1990. Power calculations and model selection for trend analysis: A comment. Ecology 71(3):1217-1220. JSTOR

Link, W.A. 1989. Testing for exponentiality against monotone failure rate average alternatives. Communications in Statistics: Theory and Methods, 18(8):3009-3017 abstract

Link, W.A. 1989. A model for informative censoring. Journal of the American Statistical Association 84(407): 749-752.

Geissler, P. H. and W. A. Link. 1988. Bias of animal population trend estimates. Pages 755-759 in E. J. Wegman, D. T. Gantz, and J. J. Miller, editors. Computing Science and Statistics: Proceedings of the 20th Symposium on the Interface. American Statistical Association, Alexandria, VA. xxxvii, 860 pp.

Link, W. A. 1988. An identifiable model for informative censoring. Pages 725-727 in E. J. Wegman, D. T. Gantz, and J. J. Miller, editors. Computing Science and Statistics: Proceedings of the 20th Symposium on the Interface . American Statistical Association, Washington, DC. xxxvii, 860 pp.

     


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