DEMOGRAPHY OF A BREEDING POPULATION OF WHIMBREL (Numenius phaeopus) NEAR CHURCHILL, MANITOBA, CANADA A Thesis submitted to the Committee on Graduate Studies in Partial Fulfillment of the Requirements for the Degree of Master of Science in the Faculty of Arts and Science TRENT UNIVERSITY Peterborough, Ontario, Canada © Johanna Perz 2014 Environmental and Life Sciences Graduate Program September 2014 ABSTRACT Demography of a Breeding Population of Whimbrel (Numenius phaeopus) Near Churchill, Manitoba, Canada Johanna Perz I used a GIS raster layer of an area in the Churchill, Manitoba region to investigate the effect of breeding habitat on demography and density of Whimbrel from 2010 through 2013. Program MARK was used to quantify adult and daily nest survival. Apparent annual survival of 0.73 ± 0.06 SE (95% CI = 0.60-0.83) did not significantly differ between sexes or habitats and was lower than expected based on longevity records and estimates for other large-bodied shorebirds. Nest success, corrected for exposure days, was highly variable, ranging from a low of 3% (95% CI = 0-12%) in 2011 to a high of 71% (95% CI = 54-83%) in 2013. The highest rate of nest survival occurred in the spring with the warmest mean temperature. I developed a generalized linear model (GLM) with a negative-binomial distribution from random plots that were surveyed for abundance to extrapolate a local breeding population size of 410 ± 230 SE and density of 3.2 birds/km2 ± 1.8 SE. The result of my study suggests that other aspects of habitat not captured by the land cover categories may be more important to population dynamics. Keywords: curlew, apparent survival, nest-site fidelity, nest success, program MARK, nest initiation, abundance, density, Earth Observation for Sustainable Development (EOSD) land cover map ii Acknowledgements I feel incredibly fortunate to have the experiences I gained throughout my education and this project in particular. I am ever grateful that my supervisor, Dr. Erica Nol, provided me with the opportunity to carry out research on Whimbrel in the equally majestic landscape of subarctic Churchill and for her confidence in my abilities. My success would not have been possible without the shared knowledge, guidance, advice, and time of my supervisor and committee members, Drs. Ken Abraham and Jeff Bowman. I am grateful to have had the opportunity to meet and work with talented and amazing people in the field, particularly Andy Johnson, Devin Turner, Christine Anderson, Danielle Gough, and Mary Heung. Data provided by Nathan Senner (2010- 2011) and Kate Ballantyne (2007-2008) were instrumental for my survival and nest success analyses. This project received appreciated financial support from an Ontario Graduate Scholarship, the Northern Scientific Training Program, the Northern Research Fund Grant of the Churchill Northern Studies Centre, the Manomet Center for Conservation Sciences, and the Natural Sciences and Engineering Research Council of Canada. I am also thankful for funding provided by Calidris, which allowed me to participate in the Western Hemisphere Shorebird Group Meeting in Santa Marta, Colombia and appreciate the extent of conservation endeavours. I also extend my gratitude to Arctic Shorebird Demographics Network and the staff of Churchill Northern Studies Centre and Trent University for logistical support. In particular, my knowledge of GIS benefited from the expertise of Tracy Armstrong. Of course, the love and support of friends and family is valued for without, achieving my goals would have been an overwhelming challenge. iii Table of Contents Abstract ........................................................................................................................................... ii Acknowledgements ........................................................................................................................ iii List of Figures ................................................................................................................................ vi List of Tables ............................................................................................................................... viii List of Appendices .......................................................................................................................... x Chapter 1: General Introduction ..................................................................................................... 1 Threats to Shorebird Populations ................................................................................................ 1 Species and Area of Study .......................................................................................................... 4 Thesis Objectives ........................................................................................................................ 7 Chapter 2: Apparent Adult Survival and Nest-Site Fidelity of Whimbrel (Numenius phaeopus) Near Churchill, Manitoba, Canada .............................................................................. 11 Abstract ..................................................................................................................................... 11 Introduction ............................................................................................................................... 13 Methods ..................................................................................................................................... 17 Study Area and Field Methods .............................................................................................. 17 Apparent Adult Survival ........................................................................................................ 19 Sensitivity Analysis ............................................................................................................... 20 Nest-site Fidelity.................................................................................................................... 21 Results ....................................................................................................................................... 23 Apparent Adult Survival ........................................................................................................ 24 Simulated Survival Adding Live Encounters ........................................................................ 25 Nest-site Fidelity.................................................................................................................... 25 Discussion ................................................................................................................................. 26 Chapter 3: Factors Affecting Variation in Whimbrel Nesting Success Near Churchill, Manitoba, Canada ......................................................................................................................... 39 Abstract ..................................................................................................................................... 39 Introduction ............................................................................................................................... 41 Methods ..................................................................................................................................... 45 Study Area and Nest Monitoring ........................................................................................... 45 Individual Variation in Nest Success..................................................................................... 47 iv Nest Initiation ........................................................................................................................ 49 Inter-annual Variation in Nest Success ................................................................................. 50 Results ....................................................................................................................................... 52 Nest Survival Models ............................................................................................................ 53 Effect of Nest Initiation Date................................................................................................. 53 Annual Variation in Nest Success ......................................................................................... 54 Discussion ................................................................................................................................. 54 Individual Variation in Nest Success..................................................................................... 54 Inter-annual Variation in Nest Success ................................................................................. 56 Chapter 4: Abundance and Distribution of Whimbrel Breeding Near Churchill, Manitoba ........ 68 Abstract ..................................................................................................................................... 68 Introduction ............................................................................................................................... 70 Methods ..................................................................................................................................... 72 Study Area ............................................................................................................................. 72 Whimbrel Survey ..................................................................................................................