Title of thesis:Dispersal, pairing success, and population structure of Harlequin Duckswintering in the Strait of Georgia, British Columbia

Supervisor: Fred Cooke

Short biography: Born in Ottawa; undergraduate at McGill University,Montreal; explored Yukon on foot, skis, and dogsled; studied red squirrelsat Kluane Park, Yukon; studied ospreys, passerines and shorebirds atManomet Obervatory, Masachusetts; studied marbled murrelets in the QueenCharlotte Islands and Clayoquot Sound; M.Sc. degree at Memorial Universityof Newfoundland, thesis on black-legged kittiwakes; travelled in Centraland South America; began research on harlequin ducks at coastal BritishColumbia with SFU in 1998.

Summary of current research: The movement patterns of individuals within and among sub-populations arean important component of population structure and demographics. Population structure is determined by the amount of mixing that occursamong breeding individuals.  Movements of individuals from their place ofbirth to their place of pairing determine the relatedness of mates and thegenetic relationships of sub-populations.  Such factors have implicationsfor the evolution of social behaviour and for potential genetic andphenotypic differentiation among groups.  They also have importantimplications for conservation.  The genetic relationships among groupsdetermine the uniqueness of sub-populations and the probabilities ofrescuing or recolonizing sub-populations that are declining or have goneextinct.  Movement rates into and out of populations must also be known inorder to separate survival from immigration and mortality from emigration. Understanding these demographic variables are vital to the conservation ofpopulations and species.

The movement patterns and population structure of Harlequin Ducks(Histrionicus histrionicus) are poorly understood.  The Harlequin Duck is asea duck that breeds at inland streams and winters on the coast on bothsides of the North American continent.  There is considerable conservationconcern for Harlequin Ducks in North America.  They are endangered on theeast coast, and on the west coast, recruitment does not appear tocompensate for losses through adult mortality.  A lack of knowledge aboutthe movement patterns of Harlequin Ducks presently interferes with attemptsat understanding population structure and demography, and thus hindersconservation efforts. 

Harlequin Ducks pair on the wintering grounds, thus their populationstructure is primarily influenced by movement on the coast.  The mechanismby which juveniles first arrive at the coast and their movement from, orphilopatry to, this initial coastal location is also a vital, poorlyunderstood component of their population structure.  This information isneeded to evaluate the consequences of subsequent movements of young birdsand adults.  Movements will result in entirely different amounts of geneflow depending on whether juveniles arrive randomly at the coast or arrivein family groups to the coastal location of their mother.

I am investigating movement patterns, dispersal, and pairing success ofHarlequin Ducks in the Strait of Georgia, British Columbia.  The existenceof a marked wintering population, and the fact that specific geographicallyseparate locations have regularly been used for banding, presents a uniqueopportunity to investigate dispersal and population structure.  Usingresightings of marked Harlequin Ducks, I am following the movements ofknown individuals of different age and sex classes and will be using amark-recapture program to determine their movement probabilities.  Inconjunction with other researchers, I am investigating the theory thatadult females migrate from the breeding streams to the coast in familygroups with their broods.  Due to winter pairing and strong femalephilopatry to moulting and wintering grounds, if juveniles arrive at thewintering grounds with their mothers, unless there is dispersal at someother stage in the life cycle, local wintering populations could becomemore genetically similar over time.

Acknowledgements / Collaborators:Collaborators, volunteers, and equipment and data managers include: ByronAndres, Brian Arquilla, Sean Boyd, Felix Breden, Rachel Botting, LynnCampbell, Fred Cooke, Pete Clarkson, Mary Jane Elkins, Frank Elkins, DanEsler, Ian Goudie, Stuart Jackson, Moira Leman, Greg Robertson, MichaelRodway, Jennifer Shore, Connie Smith, Cyndi Smith, Jason Smith, BarbaraShermann, Richard Swanston, Ken Wright, and numerous other individuals whohave helped at some time with the capture of Harlequin Ducks or the readingof bands.

Funding: NSERC of Canada, Centre for Wildlife Ecology, Canadian WildlifeService

Recent Publications / Presentations:
M.S. Rodway and H.M. Regehr. 2000. Measuring Marbled Murrelet activity invalley bottom habitat: bias due to station placement.  Journal of FieldOrnithology 17:415-422.

M.S. Rodway and H.M. Regehr. 1999. Potential nesting density of MarbledMurrelets in valley-bottom old-growth forest in Clayoquot Sound, BritishColumbia.  Pacific Seabirds 26:3-7.

H.M. Regehr and M.S. Rodway. 1999. Seabird breeding performance during two years of delayed capelin arrival in the Northwest Atlantic: a multi-speciescomparison.  Waterbirds 22: 60-67.

M.S. Rodway and H.M. Regehr. 1999. Habitat selection and reproductiveperformance of food-stressed Herring Gulls. Condor 101: 566-576.

H.M. Regehr, M.S. Rodway and W.A. Montevecchi. 1998. Anti-predator benefitsof nest-site selection in Black-legged Kittiwakes. Canadian Journal ofZoology 76: 910-915.

H.M. Regehr and W.A. Montevecchi. 1997. Interactive effects of foodshortage and predation on breeding failure of Black-legged Kittiwakes:indirect effects of fisheries activities and implications for indicatorspecies. Marine Ecology Progress Series 155: 249-260.