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Andy Royle

Research Statistician

Contact Info

Short Biography

Andy Royle has been with Patuxent Wildlife Research Center since 2004. Before that he was a statistician (1998-2004) for the U.S. FWS in the Migratory Bird Management Office where he worked primarily on waterfowl surveys and monitoring projects. Prior to that he was a visiting scientist in the Geophysical Statistics Project at the National Center for Atmospheric Reserach, Boulder, CO. He has a PhD in Statistics (1996) from North Carolina State University and a BS in Fisheries and Wildlife (1990) from Michigan State University.




J. Andy Royle
Research Statistician
USGS Patuxent Wildlife Research Center
12100 Beech Forest Rd.
Laurel, MD 20708
phone: 301-497-5846
fax: 301-497-5545


Cam, E., O. Gimenez, R. Alpizar-Jara, L. M. Aubry, M. Authier, E.G. Cooch, D.N. Koons, W.A. Link, J-Y. Monnat, J.D. Nichols, J.J. Rotella, J.A. Royle and R. Pradel. 2013. Looking for a needle in a haystack: inference about individual fitness components in a heterogeneous population. Oikos 122:739-753.

Royle, J.A. and R.M. Dorazio. 2012. Parameter-expanded data augmentation for Bayesian analysis of capture-recapture models. Journal of Ornithology 152:S521-S537.

Royle, J.A., R.B. Chandler, C. Yackulic, and J.D. Nichols. 2012. Likelihood Analysis of species occurrence probability from presence-only data for modelling species distributions. Methods in Ecology and Evolution 3:545-554.

Padding, P.I. and J.A. Royle. 2012. Assessment of bias in U.S. waterfowl harvest estimates. Wildlife Research 39:336-342.

Gopalaswamy, A.M., J.A. Royle, M. Delampady, J.D. Nichols, K.U. Karanth, and D.W. Macdonald. 2012. Density estimation in tiger populations: combining information for strong inference. Ecology 93:1741-1751.

Yamaura, Y., J.A. Royle, N. Shimada, S. Asanuma, T. Sato, H. Taki, S. Makino. 2012. Biodiversity of man-made open habitats in an underused country: A class of multispecies abundance models for count data. Biodiversity and Conservation 21:1365-1380.

Converse, S. J. and J. A. Royle. 2012. Dealing with incomplete and variable detectability in multi-year, multi-site monitoring of ecological populations. Pages 426-442 in R.A. Gitzen, J.J. Millspaugh, A.B. Cooper, and D.S. Licht. Design and Analysis of Long-term Ecological Monitoring Studies. Cambridge University Press.

Russell, R.E., J.A. Royle, R. DeSimone, M.K. Schwartz, V.L. Edwards, K.P. Pilgrim and K.S. McKelvey. 2012. Estimating abundance of mountain lions from unstructured spatial sampling. Journal of Wildlife Management 76:1551-1561.

Gopalaswamy, A., J.A. Royle, J.E. Hines, P. Singh, D. Jathanna, N. Kumar, K. U. Karanth. 2012. Program SPACECAP: Software for estimating animal density using spatially-explicit capture-recapture models. Methods in Ecology and Evolution 3:1067-1072.

Sillett, T.S., R.B. Chandler, J.A. Royle, M. Kery, S.A. Morrison. 2012. Hierarchical distance sampling models to estimate population size and habitat-specific abundance of an island endemic. Ecological Applications 22(7):1997-2006.

Graves, T. A., J. A. Royle, K. C. Kendall, P. Beier, J. B. Stetz, and A. C. Macleod. 2012. Balancing Precision and Risk: Should Multiple Detection Methods Be Analyzed Separately in N-Mixture Models? Plos1 7:12:e49410.

Royle, JA, M. Kery and J. Guelat. 2011. Spatial capture-recapture models for search-encounter data. Methods in Ecology and Evolution 2:602-611.

Converse, S. J., J. A. Royle, and R. P. Urbanek.  2012.  Bayesian analysis of multi-state data with individual covariates for estimating genetic effects on demography.  Journal of Ornithology 152(Supplement 2):S561-S572.

Royle, J. A. and R. M. Dorazio.  2012.  Parameter-expanded data augmentation for Bayesian analysis of capture-recapture models.  Journal of Ornithology 152(Supplement 2):S521-S537.

Saracco, J. F., J. A. Royle, D. F. DeSante, and B. Gardner.  2012.  Spatial modeling of survival and residency and application to the Monitoring Avian Productivity and Survivorship program .  Journal of Ornithology 152(Supplement 2):S469-S476.

Bled, F., J. A. Royle, and E. Cam.  2011.  Assessing hypotheses about nesting site occupancy dynamics.  Ecology 92(4):938-951.

Bled, F., J. A. Royle, and E. Cam.  2011.  Hierarchical modeling of an invasive spread: the Eurasian Collared-Dove Streptopelia decaocto in the United States.  Ecological Applications 21(1):290-302 .

Chandler, R. B., J. A. Royle, and D. I. King.  2011.  Inference about density and temporary emigration in unmarked populations.  Ecology 92(7):1429-1435.

Graves, T. A., K. C. Kendall, J. A. Royle, J. B. Stetz, and A. C. Macleod.  2011.  Linking landscape characteristics to local grizzly bear abundance using multiple detection methods in a hierarchical model.  Animal Conservation 14(6):652-664.

Kery, M., B. Gardner, Stoeckle T., D. Weber, and J. A. Royle.  2011.  Use of spatial capture-recapture modeling and DNA data to estimate densities of elusive animals.  Conservation Biology 25(2):356-364.

Marques, T. A., L. Thomas, and J. A. Royle.  2011.  A hierarchical model for spatial capture-recapture data: comment.  Ecology 92(2):526-528.

Martin, J., J. A. Royle, D. I. MacKenzie, H. H. Edwards, M. Kery, and B. Gardner.  2011.  Accounting for non-independent detection when estimating abundance of organisms with a Bayesian approach.  Methods in Ecology and Evolution 2(6):595-601.

Royle, J. A. and B. Gardner.  2011.  Hierarchical spatial capture-recapture models for estimating density from trapping arrays.  Pages 163-190 in Allan F. O'Connell, James D. Nichols, and K. Ullas Karanth, editors.  Camera traps in animal ecology:  Methods and analyses.   Springer, Tokyo.  xiv, 271 pp.       chapter link here:     

Royle, J. A., M. Kery, and J. Guélat.  2011.  Spatial capture-recapture models for search-encounter data.  Methods in Ecology and Evolution 2(6):602-611.

Royle, J. A., A. J. Magoun, B. Gardner, P. Valkenburg, and R. E. Lowell.  2011.  Density estimation in a wolverine population using spatial capture-recapture models.  Journal of Wildlife Management 75(3):604-611.

Yamaura, Y., J. A. Royle, K. Kuboi, T. Tada, and S. Ikeno.  2011.  Modelling community dynamics based on species-level abundance models from detection/nondetection data.  Journal of Applied Ecology 48(1):67-75.

Saracco, J.F., J.A. Royle, D.F. DeSante and B. Gardner. 2010. Modeling spatial variation in avian survival and residency probabilities. Ecology 91:1885-1891.

Gardner, B.,J. Reppucci, M. Lucherini and J.A. Royle.  2010.  Spatially-explicit inference for open populations: estimating demographic parameters from camera-trap studies. Ecology 90:1106-1115.

Dorazio, R.M. M. Kery, J.A. Royle and M. Plattner. 2010. Models for inference in dynamic metacommunity systems. Ecology 91:2466-2475.

Griffith, E.H., J.R. Sauer and J.A. Royle. Traffic effects on bird counts on North American Breeding Bird Survey Routes. Auk.

Hines, J.E., J.D. Nichols, J.A. Royle, D.I. MacKenzie, A.M. Gopalaswamy, N.S. Kumar and K.U. Karanth. 2010. Tigers on trails: occupancy modeling for cluster sampling. Ecological Applications 20(5) 1456-1466.

Zipkin, E.F., Gardner, B, Gilbert, A.T., O'Connell, Jr., A.F., Royle, J.A., Silverman, E.D. 2010. Distribution patterns of wintering sea ducks in relation to the North Atlantic Oscillation and local environmental characteristics. Oecologia 163:893-902.

Zipkin, E.F., J.A. Royle, D.K. Dawson, and S. Bates. 2010. Multi-species occurrence models to evaluate the effects of conservation and management actions. Biological Conservation 143:479-484.

Kery, M., J.A. Royle, H. Schmid, M. Schaub, Bernard Volet, Guido Häfliger, and Niklaus Zbinden. 2010. Using site-occupancy models to Correcting population trend estimates from opportunistic observations for variation in observation effort using site occupancy modeling. Conservation Biology

Kery, M., and J.A. Royle. 2010. Hierarchical modeling and estimation of abundance and population trends in metapopulation designs. Journal of Animal Ecology 79:453-461.

Gardner,  B., Royle,  J.A., Wegan, M.T.,  Rainbolt,  R.E., and Curtis, P.D. 2010.  Estimating black bear density using DNA data from hair snares. Journal of Wildlife Management 74(2):318-325.

Weir, L.A., I.J. Fiske and J.A. Royle. 2009. Trends in Anuran Occupancy  from  Northeastern  States of the North  American Amphibian Monitoring Program. Herpetological Conservation and Biology 4:389-402

Royle, J.A., K.U. Karanth, A.M. Gopalaswamy, and N.S. Kumar. 2009. Bayesian inference in camera trap studies using a class of spatial capture-recapture models. Ecology 90:3233-3244.

Kery, M., R.M. dorazio, L. Soldaat, A. van Strien, A. Zuiderwijk, and J.A. Royle. 2009. Trend estimation in populations with imperfect detection. Journal of Applied Ecology 46:1163-1172.

Franklin, M., S. Droege, D. Dawson and J.A. Royle. 2009. Nightly and seasonal patterns of calling in common true katydids (Orthoptera: Tettigoniidae: Pterophylla camellifolia). 18(1) 15-18.

Zipkin,   E.F.,  A.  DeWan  and  J.A.  Royle.   2009. Impacts   of  forest fragmentation on species richness: a hierarchical approach to community modeling. Journal of Applied Ecology. 46: 815-822.

Russell,  R.E., J.A.  Royle,  V.A. Saab, J.F.  Lehmkuhl,  W.M.  Block and J.R. Sauer.  2009. Modeling the effects of environmental disturbance on wildlife communities: avian responses to prescribed fire.  Ecological Applications 19:1253-1263.

Forcada, J., D. Malone, J.A. Royle and I.J. Staniland. 2009. Modelling predation by transient leopard seals for an ecosystem-based management of Southern Ocean fisheries. Ecological Modelling 220: 1513-1521.

Gardner, B., J.A. Royle and M.T. Wegan. 2009. Hierarchical models for estimating density from DNA mark-recapture studies. Ecology 90:1106-1115.

Kery, M., J.A. Royle, M. Plattner,  and R.M. Dorazio. 2009. Species richness and occupancy  estimation in communities subject to temporary emigration. Ecology 90:1279-1290.

Royle, J.A., J.D. Nichols, K.U. Karanth and A. Gopalaswamy. 2009. A hierarchical model for estimating density in camera-trap studies. Journal of Applied Ecology 46:118-127.

Royle, J.A. and R.M. Dorazio. 2008. Hierarchical Modeling and Inference in Ecology: The Analysis of Data from Populations, Metapopulations, and Communities. Academic Press, San Diego, CA. xviii, 444 pp. Book Web Supplement: Data files, R and WinBUGS code

Royle, J.A. 2008. Modeling individual effects in the Cormack-Jolly-Seber Model: A state-space formulation. Biometrics 64(2):364-370.

Royle, J.A. and K. Young. 2008. A hierarchical model for spatial capture-recapture data. Ecology 89(8):2281-2289.

Hooten, M.B., C.K. Wikle, R.M. Dorazio and J.A. Royle. 2007. Hierarchical spatiotemporal matrix models for characterizing invasions. Biometrics 63(2):558-567.

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.

Royle, J.A., M. Kéry, R. Gautier, and H. Schmid. 2007. Hierarchical spatial models of abundance and occurrence from imperfect survey data. Ecological Monographs 77(3):465-481.

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.


Royle, J.A., J.D. Nichols and M. Kéry. 2005. Modeling Occurrence and Abundance of Species with Imperfect Detection. Oikos 110(2):353-359.


Dorazio, R.M. and J.A. Royle. 2005. Estimating size and composition of biological communities by modeling the occurrence of species. Journal of the American Statistical Association 100(470):389-398.


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.


Royle, J.A., and P. Garrettson. 2005. The effect of reward band value on mid-continent mallard band reporting rates. Journal of Wildlife Management 69(2):800-804.

Royle, J.A., D.K. Dawson, and S. Bates. 2004. Modeling abundance effects in distance sampling. Ecology 85(6):1591-1597.

Royle, J.A. 2004. N-Mixture Models for estimating population size from spatially replicated counts. Biometrics 60(1):108-115.

Doherty, P.F., G. Sorci, J.A. Royle, J.E. Hines, J.D. Nichols, and T. Boulinier. 2003. Sexual selection affects local extinction and turnover. Proceedings of the National Academy of Science 100(10):5858-5862.


Royle, J.A. and J.D. Nichols. 2003. Estimating abundance from repeated presence-absence data or point counts. Ecology 84(3):777-790.


Royle, J.A., M. Koneff and R. Reynolds. 2002. Spatial modeling of wetland condition in the U.S. Prairie Pothole Region. Biometrics 8(2):104-113.


My Science Topics

Science Topic
Techniques and Methodsmathematical modeling
Techniques and Methodsstatistical analysis
Ecology and Environmentbiodiversity
Ecology and Environmentecological processes

Quantitative Ecology

I am a Research Statistician engaged in the development of statistical methods and analytic tools for animal demographic modeling, statistical inference and sampling wildlife populations and communities. My current research is focused on hierarchical models of animal abundance and occurrence, Bayesian analysis in ecology, spatial modeling, and the development of spatial capture-recapture models.

Hierarchical Modeling Book (with R.M. Dorazio)

Image of Hierarchical Modeling Book (with R.M. Dorazio)

Published by Academic Press in 2008, this book describes a general and flexible framework for modeling and inference in ecological systems based on hierarchical models, with a strict focus on the use of probability models and parametric inference. Hierarchical models represent a paradigm shift in the application of statistics to ecological inference problems because they combine explicit models of ecological system structure or dynamics with models of how ecological systems are observed. The principles of hierarchical modeling are developed and applied to problems in population, metapopulation, community, and metacommunity systems.

e-book version (available to all USGS employees) use this URL

Contact Information

Andy Royle
12100 Beech Forest Road
Laurel, MD 20708
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