Menu

Volume 43, No. 2

Search by author or title:

Age and sex ratios of sea ducks wintering in the Strait of Georgia, British Columbia: Implications for monitoring


Authors

MICHAEL S. RODWAY1, HEIDI M. REGEHR1, W. SEAN BOYD2 & SAMUEL A. IVERSON3
1Wildwing Environmental Research, Box 47, Gold Bridge, British Columbia, V0K 1P0, Canada (msrodway@alumni.sfu.ca)
2Science and Technology Branch, Environment Canada, Pacific Wildlife Research Centre, RR#1, 5421 Robertson Road, Delta, British Columbia, V4K 3N2, Canada
3Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario, K1S 5B6, Canada 

Citation

RODWAY, M.S., REGEHR, H.M., BOYD, W.S. & IVERSON, S.A. 2015. Age and sex ratios of sea ducks wintering in the Strait of Georgia, British Columbia: Implications for monitoring. Marine Ornithology 43: 141 - 150

Received 7 January 2015, accepted 9 April 2015

Date Published: 2015/10/15
Date Online: 2017/02/28
Key words: age and sex segregation, age ratio, demographics, goldeneye, Harlequin Duck, immature plumage, Mergini, sea ducks, scoter, sex ratio, waterfowl

Abstract

In research on sea ducks, winter age and sex ratios provide valuable demographic data that are difficult to obtain by other means. Our objectives were to determine spatial, temporal, and density-related variability in (1) age and sex ratios for five sea duck species and (2) proportions of adult males for eight species that winter in the Strait of Georgia, British Columbia, Canada. Kilometre-long shoreline sections (n = 49–62) were surveyed in early February in three years: 2003, 2004, and 2014. Annual estimates for male age ratio (first year:adult male) varied significantly for Black Scoter Melanitta americana (0.071 to 0.170), Surf Scoter M. perspicillata (0.064 to 0.101) and Harlequin Duck Histrionicus histrionicus (0.068 to 0.138). Regional differences in male age ratio were found for Barrow's Goldeneye Bucephala islandica (0.034 to 0.197) and Common Goldeneye B. clangula (0.033 to 0.165), and more complex interactions were found between regions by year for Surf Scoter. Sex ratios were less variable than age ratios and varied consistently by year and region only for Common Goldeneye. Adult male proportions were correlated with but varied more than sex ratios and showed significant differences by year for Surf Scoter, Common Goldeneye and Bufflehead B. albeola and by region for Surf Scoter, Common Goldeneye, Bufflehead and Red-breasted Merganser Mergus serrator. Based on previous research that calculated expected confidence limits from different numbers of occupied survey sections, the sampling intensity for each species obtained in this study provided age ratio estimates with 95% confidence limits likely within ± 5% for Surf Scoters and ± 3% for Harlequin Ducks. Regional and density-related differences in age ratios, sex ratios and adult male proportions indicated segregation and emphasize the need for broad-scale sampling to achieve representativeness. Inter-annual differences may indicate demographic changes, but few comparative data exist, and several consecutive years of surveys are needed to provide baseline data. 

References


ALDERFER, J. 2006. Complete birds of North America. Washington, DC: National Geographic Society.

ANDERSON, E.M., BOWER, J.L., NYSEWANDER, D.R., EVENSON, J.R. & LOVVORN., J.R. 2009. Changes in avifaunal abundance in a heavily used wintering and migration site in Puget Sound, Washington, during 1966–2007. Marine Ornithology 37: 19–27.

BARKER, R.J. & WHITE, G.C. 2001. Joint analysis of live and dead encounters of marked animals. Proceedings of the 2nd International Wildlife Management Congress, 28 June–2 July 1999, Gödöllo, Hungary. Bethesda, MD: The Wildlife Society.

BELLROSE, F.C., SCOTT, T.G., HAWKINS, A.S. & LOW, J.B. 1961. Sex ratios and age ratios in North American ducks. Illinois Natural History Survey Bulletin 27: 391–474.

BLUMS, P. & MEDNIS, A. 1996. Secondary sex ratios in Anatinae. Auk 113: 505–511.

BOWER, J.L. 2009. Changes in marine bird abundance in the Salish Sea: 1975 to 2007. Marine Ornithology 37: 9–17.

CAMPBELL, R.W., DAWE, N.K., MCTAGGART-COWAN, I., COOPER, J.M., KAISER, G.W. & MCNALL, M.C.E. 1990. The birds of British Columbia: Volume 1 – nonpasserines (introduction, loons through waterfowl). Victoria, BC: Royal British Columbia Museum.

CARON, C.M. & PATON, P.W.C. 2007. Population trends and habitat use of Harlequin Ducks in Rhode Island. Journal of Field Ornithology 78: 254–262.

CITTA, J.J., QUAKENBUSH, L.T. & TARAS, B.D. 2014. Estimation of calf:cow ratios of Pacific Walruses for use in population modeling and monitoring. Marine Mammal Science 30: 20–43.

CLOBERT, J. & LEBRETON, J.-D. 1991. Estimation of demographic parameters in bird populations. In: Perrins, C.M., Lebreton, J.-D. & Hirons, G.J.M. (Eds.) Bird population studies: relevance to conservation and management. Oxford: Oxford University Press. pp. 75–104.

COOKE, F., ROBERTSON, G.J., SMITH, C.M., GOUDIE, R.I. & BOYD, W.S. 2000. Survival, emigration, and winter population structure of Harlequin Ducks. Condor 102: 137–144.

COUPE, M. & COOKE, F. 1999. Factors affecting the pairing chronologies of three species of mergansers in southwest British Columbia. Waterbirds 22: 452–458.

COWARDIN, L.M. & BLOHM, R.J. 1992. Breeding population inventories and measures of recruitment. In: Batt, B.D.J., Afton, A.D., Anderson, M.G., Ankney, C.D., Johnson, D.H., Kadlec, J.A. & Krapu, G.L. (Eds). Ecology and management of breeding waterfowl. Minneapolis: University of Minnesota Press. pp. 422–445.

CREWE, T., BARRY, K., DAVIDSON, P. & LEPAGE, D. 2012. Coastal waterbird population trends in the Strait of Georgia 1999–2011: Results from the first 12 years of the British Columbia Coastal Waterbird Survey. British Columbia Birds 22: 8–35.

DE LA CRUZ, S.E.W., TAKEKAWA, J.Y., SPAGENS, K.A., YEE, J., GOLIGHTLY, R.T., MASSEY, G., HENKEL, L.A., LARSEN, R.S. & ZICCARDI, M. 2013. Post-release survival of surf scoters following an oil spill: An experimental approach to evaluating rehabilitation success. Marine Pollution Bulletin 67: 100–107.

EADIE, J.M., SAVARD, J.-P.L. & MALLORY, M.L. 2000. Barrow's Goldeneye (Bucephala islandica). In: Poole, A & Gill, F. (Eds.). The birds of North America, No. 548. Washington, DC: The Academy of Natural Sciences and the American Ornithologists' Union.

ESLER, D., SCHMUTZ, J.A., JARVIS, R.L. & MULCAHY, D.M. 2000. Winter survival of adult female harlequin ducks in relation to history of contamination by the Exxon Valdez oil spill. Journal of Wildlife Management 64: 839–847.

FLINT, P.L. 2015. Population dynamics of sea ducks: using models to understand the causes, consequences, evolution, and management of variation in life-history characteristics. In: Savard, J.-P.L., Derksen, D.V. Esler, D. & Eadie, J.M. (Eds.) Ecology and conservation of North American sea ducks. Studies in Avian Biology series (No. 46). CRC Press, Boca Raton, FL. pp. 63–96.

GARDARSSON, A. 2008. Harlequin Ducks in Iceland. Waterbirds 31 (Special Publication 2): 8–14.

GAYDOS, J.K. & PEARSON, S.F. 2011. Birds and mammals that depend on the Salish Sea: a compilation. Northwestern Naturalist 92: 79–94.

GOUDIE, R.I., BRAULT, S., CONANT, B., KONDRATYEV, A.V., PETERSEN, M.R. & VERMEER, K. 1994. The status of sea ducks in the north Pacific Rim: toward their conservation and management. Transactions of the North American Wildlife and Natural Resources Conference 59: 27–49.

HARRIS, N.C., KAUFFMAN, M.J. & MILLS, L.S. 2008. Inferences about ungulate population dynamics derived from age ratios. Journal of Wildlife Management 72: 1143–1151.

HICKLIN, P.W. & BARROW, W.R. 2008. Wintering Harlequin Ducks on the Wolves Archipelago, Bay of Fundy. Waterbirds 31 (Special Publication 2): 130–132.

IVERSON, S.A. & ESLER, D. 2010. Harlequin Duck population injury and recovery dynamics following the 1989 Exxon Valdez oil spill. Ecological Applications 20: 1993–2006.

IVERSON, S.A., ESLER, D. & BOYD, W.S. 2003. Plumage characteristics as an indicator of age class in the Surf Scoter. Waterbirds 26 :56–61.

IVERSON, S.A., SMITH, B.D. & COOKE, F. 2004. Assessing age and sex distributions of wintering Surf Scoters: implications for the use of age ratios as an index of recruitment. Condor 106: 252–262.

IVERSON, S.A., BOYD, W.S., REGEHR, H.M. & RODWAY, M.S. 2006. Sex and age-specific distributions of sea ducks wintering in the Strait of Georgia, British Columbia: implications for the use of age ratios as an index of recruitment. Technical Report Series No. 459. British Columbia: Canadian Wildlife Service, Pacific and Yukon Region. 

JOHNSON, D.H., NICHOLS, J.D. & SCHWARTZ, M.D. 1992. Population dynamics of breeding waterfowl. In: Batt, B.D.J., Afton, A.D., Anderson, M.G., Ankney, C.D., Johnson, D.H., Kadlec, J.A. & Krapu, G.L. (Eds.) Ecology and management of breeding waterfowl. Minneapolis: University of Minnesota Press. pp. 446–485.

KAHLERT, J., COUPE, M. & COOKE, F. 1998. Winter segregation and timing of pair formation in Red-breasted Mergansers Mergus serratus. Wildfowl 49: 161–172.

LEUKERING, T. 2012. Goldeneye bill coloration. Colorado Birds 46: 159–162.

LUDWICHOWSKI, I., BARKER, R. & BRÄGER, S. 2002. Nesting area fidelity and survival of female Common Goldeneyes Bucephala clangula: are they density-dependent? Ibis 144: 452–460.

MITCHELL, G.J. 1952. A study of the distribution of some members of the Nyrocinae wintering on the coastal waters of southern British Columbia. Master's Thesis. Vancouver: University of British Columbia.

MITTELHAUSER, G.H., DRURY, J.B. & CORR, P.O. 2002. Harlequin Duck (Histrionicus histrionicus) in Maine, 1950–1999. Northeastern Naturalist 9: 163–182.

MITTELHAUSER, G.H. 2008. Apparent survival and local movements of Harlequin Ducks wintering at Isle au Haut, Maine. Waterbirds 31 (Special Publication 2): 138–146.

PETERSEN, M.R. & HOGAN, M.E. 1996. Seaducks: a time for action. International Waterfowl Symposium 7: 62–67.

REGEHR, H.M. 2011. Movement rates and distances of wintering Harlequin Ducks: implications for population structure. Waterbirds 34: 19–31.

ROBERTSON, G.J. 2008. Using winter juvenile/adult ratios as indices of recruitment in population models. Waterbirds 31 (Special Publication 2): 152–158.

RODWAY, M.S. 2007. Timing of pairing in waterfowl I: reviewing the data and extending the theory. Waterbirds 30: 488–505.

RODWAY, M.S., REGEHR, H.R. & COOKE, F. 2003a. Sex and age differences in distribution, abundance, and habitat preferences of wintering Harlequin Ducks: implications for conservation and estimating recruitment. Canadian Journal of Zoology 81: 492–503.

RODWAY, M.S., REGEHR, H.R., ASHLEY, J., CLARKSON, P.V., GOUDIE, R.I., HAY, D.E., SMITH, C.M. & WRIGHT, K.G. 2003b. Aggregative response of Harlequin Ducks to herring spawn in the Strait of Georgia, British Columbia. Canadian Journal of Zoology 81: 504–514.

ROSENBERG, D.H. & PETRULA, M.J. 1998. Status of Harlequin Ducks in Prince William Sound, Alaska, after the Exxon Valdez oil spill, 1995–97. Exxon Valdez Oil Spill Restoration Project Final Report; Restoration Project 97427. Anchorage: Alaska Department of Fish Game, Division of Wildlife Conservation.

ROSENBERG, D.H. & PETRULA, M.J., HILL, D.D. & CHRIST, A.M. 2005. Harlequin duck population dynamics: measuring recovery from the Exxon Valdez oil spill. Exxon Valdez Oil Spill Restoration Project Final Report; Restoration Project 040407. Anchorage: Alaska Department of Fish Game, Division of Wildlife Conservation.

SAUER, J.R., SCHWARTZ, S. & HOOVER, B. 1996. The Christmas Bird Count Home Page. Version 95.1. Laurel, MD: Patuxent Wildlife Research Center. [Available online at: http://www.mbr-pwrc.usgs.gov/bbs/cbc.htm; accessed 9 June 2015]

SAVARD, J.-P.L. 1989. Birds of rocky coastlines and pelagic waters in the Strait of Georgia. In: Vermeer, K. & Butler, R.W. (Eds.) The ecology and status of marine and shoreline birds in the Strait of Georgia, British Columbia. Ottawa: Canadian Wildlife Service Special Publication. pp. 132–141.

SEA DUCK JOINT VENTURE. 2008. Sea Duck Joint Venture Strategic Plan 2008–2012. [Available online at: http://www.seaducks.org/resources/sea-duck-joint-venture-strategic-plan-2008-2012; accessed 9 June 2015].

SMITH, C., COOKE, F. & GOUDIE, R.I. 1998. Ageing Harlequin Duck Histrionicus histrionicus drakes using plumage characteristics. Wildfowl 49: 245–248.

SMITH, C.M., GOUDIE, R.I. & COOKE, F. 2001. Winter age ratios and the assessment of recruitment of Harlequin Ducks. Waterbirds 24: 39–44.

SOKAL, R.R. & ROHLF, F.J. 1995. Biometry. New York: W.H. Freeman and Company.

SUN, Y.-H., BRIDGMAN, C.L., WU, H.-L., LEE, C.-F., LIU, M., CHIANG, P.-J. & CHEN, C.-C. 2011. Sex ratio and survival of Mandarin Ducks in the Tachia River of central Taiwan. Waterbirds 34: 509–513.

VERMEER, K. 1982. Food and distribution of three Bucephala species in British Columbia waters. Wildfowl 33: 22–30.

WELLER, M.W. 1976. Molts and plumages of waterfowl. In: Bellrose, F.C. (Ed.) Ducks, geese, and swans of North America. Harrisburg: Stackpole Books. pp. 34−38.

WILSON, H.M., FLINT, P.L., POWELLL, A.N., GRAND, J.B. & MORAN, C.L. 2012. Population ecology of breeding Pacific common eiders on the Yukon-Kuskokwim Delta, Alaska. Wildlife Monographs 182: 1–28.

Search by author or title:

Browse previous volumes: