SITE FIDELITY

Activity pattern, diet, and feeding efficiency of harlequin ducks breeding in northern Labrador

Rodway, M. S., 1998, , Can. J. Zool. 76:902-909..

Annual variation in common eider egg size: effects of temperature, clutch size, laying date and laying sequence. Robertson, G. J. 1995. Canadian Journal of Zoology 73: 1579-1587.

Behaviour and chronology of pair formation by Harlequin Ducks Histrionicus histrionicus. Gowans, B., G. J. Robertson, and F. Cooke. 1997. Wildfowl 48: 135-146.

Behaviour and chronology of pair formation in Harlequin Ducks at White Rock, British Columbia. Gowans, B., G. J. Robertson and F. Cooke. 3rd Harlequin Duck Working Group meeting, Delta, BC. 11 March 1996 (oral presentation by B. Gowans).

Behaviour and ecology of sea ducks. Goudie, R. I., M. R. Petersen and G. J. Robertson. (eds.). 1999. Canadian Wildlife Service Occasional Papers Series No. 100, Ottawa.

Cavity nesting by harlequin ducks in the Pacific northwest, Cassirer, E. F., Schirato, G., Sharpe, F., Groves, C. R., and Anderson, R. N., 1993, Wilson Bull. 105:691-694..

Clutch, egg and body size variation among populations of common eiders breeding in Hudson Bay, Robertson, G. J., A. Reed and H. G. Gilchrist. submitted. Canada. Ecography

Common Eider (Somateria mollissima).

Goudie, R. I., G. J. Robertson and A. Reed. In The Birds of North America. (A. Poole and F. Gill, eds.). Birds of North America, Inc., Philadelphia, PA.

Contaminants and sea ducks in Alaska and the circumpolar region,

Henny, C. J., Rudis, D. D., Roffe, T. J., and Robinson-Wilson, E., 1995, Environ. Health Perspect. 103:41-49..

Costs and benefits of early pairing in the Harlequin Duck.

Torres, R., F. Cooke, G. Robertson, and S. Boyd Animal Behaviour Society, Annual Meeting, Lewisburg, PA. 27 June 1999 and Seventh congress of the European Society for Evolutionary Biology, Barcelona, Spain. 26 August 1999 (poster).

Diet and habitat constraints of sea ducks wintering in the Belcher Islands polynyas, Nunavut, Canada. Gilchrist, H.G., G.J. Robertson and K.A. Hobson. 23rd Waterbird Society Annual Meeting, Grado, Italy. 9 November 1999 (oral presentation).

Diets and morphology of digestive organs of five species of sea ducks wintering in Newfoundland Goudie, R. I. and Ryan, P. C., 1991, J. Yamashina Inst. Ornithol. 22:1-8.

Delayed capelin (Mallotus villosus) availability influences large gull predatory behaviour on black-legged kittiwakes (Rissa tridactyla), causing a reduction in breeding success. Massaro, M., J.W. Chardine, I.L. Jones and G.J. Robertson. submitted. Canadian Journal of Zoology

Discovery of a harlequin duck nest in eastern North America,

Rodway, M. S., Rodway, M. S., Fong, I., and Montvecchi, W. A., 1998, Wilson Bull. 110:282-285..

Distribution and population status of harlequin ducks in Idaho,

Cassirer, E. F., Groves, C. R., and Wallen, R. L., 1991, Wilson Bull. 103:723-725..

Distribution and status of harlequin ducks (Histrionicus histrionicus) on the Targhee National Forest Atkinson, E. C. and Atkinson, M. L., 1990, , Id. Dep. Fish Game, Boise. 18pp..

The ecology, status, and conservation of marine and shoreline birds on the

west coast of Vancouver Island, Vermeer, K., Butler, R. W., and Morgan, K. H., 1992,

Can. Wildl. Servl Occas. Pap. 75..

Egg adoption can explain joint egg-laying in common eiders.

Robertson, G. J. 1998. Behavioral Ecology and Sociobiology 43: 289-296.

Egg-laying time and laying interval in the Common Eider.

Watson, M. D., G. J. Robertson, and F. Cooke. 1993 Condor 95: 869-878.

Estimating animal movement using Capture-Mark-Recapture models. Investigation of animal movements: analytical techniques across the animal kingdom

Robertson, G. J.. Symposium held at the ACWERN annual meeting, St. John‚s, NF. 1 November 1998 (oral presentation).

 

Estimating movement with Capture-Mark-Recapture models. Pp. 67-72 in Investigation of Animal Movement:

Robertson, G. J. 1999. Workshop Proceedings. (F. Huettmann and J. Bowman, eds.). Sir James Dunn Wildlife Research Centre, University of New Brunswick, Fredericton, Canada.

Evidence of long-term pair bonds in Harlequin Ducks, (Histrionicus histrionicus).  Smith, C. M., F. Cooke, G. J. Robertson, R. I. Goudie and W. S. Boyd. Harlequin Duck Working Group, 4th Biennial Symposium, Newport, Oregon. 2 March 1998 and Society of Canadian Ornithologists, Annual Meeting, Vancouver, BC. 4 August 1998 (oral presentations by C. M. Smith).

Evidence for population declines among Common Eiders breeding in the Belcher Islands, Northwest Territories. Gilchrist, H. G. and G. J. Robertson. Pacific Seabird Group, Monterrey, CA. January 1998 (poster).

Evidence for population declines among Common Eiders breeding in the Belcher Islands, Northwest Territories Robertson, G. J. and H. G. Gilchrist.. North American Ornithological Conference, St. Louis, Missouri. 9 April 1998 (poster).

Evidence for population declines among Common Eiders breeding in the Belcher Islands, Northwest Territories.

Robertson, G. J., and H. G. Gilchrist. 1998. Arctic 51: 378-385.

Estimating temporary emigration rates with supplementary information: an example with Harlequin Ducks. Robertson, G. J., F. Cooke, R. I. Goudie and W. S. Boyd. 1997. The Ring 19:169-178.

 

Evidence of breeding declines among common eider ducks breeding in the Belcher Islands, Nunavut, Canada. Gilchrist, H.G., and G.J. Robertson. 23rd Waterbird Society Annual Meeting, Grado, Italy. 9 November 1999 (poster).

Evidence of spring staging and migration route of an individual breeding Harlequin Duck Histrionicus histrionicus in southern British Columbia. Wright, K. G., G. J. Robertson and R. I. Goudie. 1998. Canadian-Field Naturalist 112: 518-519.

Factors affecting nest site selection and nesting success in the Eider Somateria mollissima. Robertson, G. J. 1995. Ibis 137: 109-115.

Female age and egg size in the Lesser Snow Goose. Robertson, G. J., E. G. Cooch, D. B. Lank, R. F. Rockwell, and F. Cooke. 1994. Journal of Avian Biology 25: 149-155.

Frequency, timing and costs of intraspecific nest parasitism in the Common Eider. Robertson, G. J., M. D. Watson and F. Cooke. 1992. Condor 94: 871-879.

Habitat use by harlequin ducks breeding in Hebron Fiord, Labrador

Rodway, M. S., 1998, , Can. J. Zool. 76:897-901..

Habitat Selection And Moult Characteristics Of Male Barrow's Goldeneye In Northern Yukon.

Debbie E. van de Wetering & Tony D. Williams.

Harlequin Duck (Histrionicus histrionicus).

Robertson, G. J. and R. I. Goudie. 1999. In: The Birds of North America, No. 466. (A. Poole and F. Gill, eds.). Birds of North America, Inc., Philadelphia, PA.

Harlequin duck ecology in Idaho: Cassirer, E. F. and Groves, C. R.,

1991, 1987-1990, Id. Dep. Fish Game, Boise. 93pp..

Harlequin duck in Benton County, Ross, S., 1991, Loon 63:140-141..

Heavy metals in seaducks and mussels from Misty Fjords National Monument in southeast Alaska, Franson, J. C., Koehl, P. S., Derksen, D. V., Rothe, T. C., and Bunck, C. M. Moore J. F., 1995, Environ. Monit. Assess. 36:149-167..

Hemolytic anemia in wild seaducks caused by marine oil pollution,

Yamato, O., Goto, I., and Maede, Y., 1996, J. Wildl. Dis. 32:381-384..

 

Herring Gull Larus argentatus predation on Leach‚s Storm-Petrels Oceanodroma leucorhoa breeding on Great Island, Newfoundland.

Stenhouse, I. J., G. J. Robertson and W. A. Montevecchi. submitted. Atlantic Seabirds

Homing of subadult oldsquaws, Alison, R. M., 1977, Auk 94:383-384..

Immediate impact of the 'Exxon Valdez' oil spill on marine birds,

Piatt, J. F., Lensink, C. J., Butler, W., Kendziorek, M., and Nysewander, D. R., 1990, Auk 107:387-397..

Interspecific killing in the Pacific Loon.

Robertson, G. J. 1993. Wilson Bulletin 105: 534-535.

Intraclutch egg-size variation and hatching success in the common eider.

Robertson, G. J., and F. Cooke. 1993. Canadian Journal of Zoology 71: 544-549.

Joint egg-laying in eider ducks: nest parasitism or egg-adoption? Robertson, G. J. Pacific Ecology Conference, Bamfield Marine Biology Station, BC. 5 March 1994 (oral presentation).

Long-term pair bonds in Harlequin Ducks. Smith, C. M., F. Cooke, G. J. Robertson, R. I. Goudie and W. S. Boyd. 2000. Condor 102: 201-205.

Modeling the population demography of Harlequin Ducks. Robertson, G. J. First North American Duck Symposium and Workshop, Baton Rouge, LA. 13 February 1997 and Pacific Ecology Conference, Bamfield, BC. 22 February 1997 (poster).

Moult and the basic plumage of male Harlequin Ducks.

Cooke, F., G. J. Robertson, R. I. Goudie, W. S. Boyd. 3rd Harlequin Duck Working Group meeting, Delta, BC. 11 March 1996 (oral presentation by F. Cooke).

Moult chronology and the timing of pairing in Harlequin Ducks.

Robertson, G. J., F. Cooke, R. I. Goudie and W. S. Boyd. Pacific Ecology Conference, Friday Harbour Laboratories, Wash. 5 February 1996 (oral presentation).

 

 

Moulting and wintering site philopatry in Harlequin Ducks. Robertson, G. J., F. Cooke, R. I. Goudie, and W. S. Boyd. Northwest Section of the Wildlife Society Conference, Banff, Alta. 30 March 1996 and 3rd Harlequin Duck Working Group meeting, Delta, BC. 11 March 1996 (oral presentations).

Moulting sites of sea ducks and other marine birds in Frederick Sound,

southeast Alaska, Butler, R. W., 1998, Can. Field-Nat. 112:346-347..

Molt speed predicts pairing success in male Harlequin Ducks.

Robertson, G. J. North American Ornithological Conference, St. Louis, Missouri. 8 April 1998 (oral presentation: Best Student Paper Award, Colonial Waterbird Society).

Moulting studies of Harlequin Ducks.

Cooke, F. and G. J. Robertson. Harlequin Duck Working Group, 4th Biennial Symposium, Newport, Oregon. 2 March 1998. (oral presentation by F. Cooke).

Molt and the basic plumage of male Harlequin Ducks.

Cooke, F., G. J. Robertson, R. I. Goudie, and W. S. Boyd. 1997. Condor 99: 83-90.

Moult speed predicts pairing success in male harlequin ducks

Robertson, G. J., Cooke, F., and Boyd, W. S., 1998, , Anim. Behav. 55:1677- 1684..

Movements and survival of molting and wintering Harlequin Ducks. Robertson, G. J., F. Cooke, R. I. Goudie, and W. S. Boyd. First North American Duck Symposium and Workshop, Baton Rouge, LA. 13 February 1997 (oral presentation).

Movements and temporary emigration of moulting and wintering Harlequin Ducks Robertson, G. J., F. Cooke, R. I. Goudie, and W. S. Boyd.. EURING 97, University of East Anglia, Norwich, UK. 8 April 1997 (poster).

Observations of geese and other birds in west Greenland, 1989 and 1990,

Bennike, O., 1990, Dan. Ornithol. Foren. Tidsskr. 84:145-150..

Observations of harlequin ducks, other waterfowl, and raptors in Labrador

Goudie, R. I., Lemon, D., and Brazil, J., 1994, , 1987-1992, Can. Wildl. Serv. Tech. Rep. 207..

Observations of marine birds and mammals wintering at polynyas and ice edges in the Belcher Islands, Nunavut, Canada.

Gilchrist, H. G., and G. J. Robertson. in press. Arctic 53.

Oil, seabirds, and science: the effects of the Exxon Valdez oil spill

Wiens, J. A., 1996, , Bioscience 46:587-597.

Pairing decisions in the Harlequin Duck: costs and benefits.

Torres, R., F. Cooke, G. J. Robertson and W. S. Boyd. submitted. Auk

Phylogeny and evolutionary ecology of modern seaducks (Anatidae: Mergini),

Livezey, B. C., 1995, Condor 97:233-255..

Philopatry in Harlequin Ducks moulting in southern British Columbia

Andre M. Breault and Jean-Pierre L. Savard

Philopatry in nesting adult female spectacled eiders at Kigigak Island, Yukon Delta National Wildlife Refuge, Alaska.

Moran, Tina L. Institute of Arctic Biology, Department of Biology and Wildlife,

University of Alaska, Fairbanks, Alaska 99775

ABSTRACT

In response to the dramatic decline of the species (early 1970's to 1990's) on the

Yukon-Kuskokwim Delta, I conducted a nesting ecology study on spectacled eiders

(Somateria fischeri) at Kigigak Island from 1992-1996. The Kigigak Island population

has had relatively high nest success between 1992-1996 (92%, 63%, 70%, 64%, and

82%, respectively). More than 50% of the nesting females have been marked (n=161).

Preliminary results show that 70% of the marked females have returned to nest at least

once following their banding year and that 52% returned at least two consecutive years.

The spectacled eider estimate on Kigigak is relatively high compared with return rates

reported for other duck species, including buffleheads (Bucephala albeola)( 44-50%)

and mallards (Anas platyrhynchos) (40-46%). Preliminary results also show that

returning females move an average of 200 m from previously used nest sites. I am

currently examining relationships between partial predation, clutch size, nesting

chronology and distances moved between individual female's nest sites.

 

 

Population dynamics of Harlequin Ducks in British Columbia and Alberta. Biology and Management of Species and Habitats at Risk Conference,

Smith, C.M., F. Cooke, G.J. Robertson, R.I. Goudie, and W.S. Boyd. University College of the Cariboo, Kamloops, BC. 16 February 1999 (oral presentation by C.M. Smith).

Population status and trends of Razorbills in Canada. Robertson, G.J., G. Chapdelaine, A. W. Diamond, F. Huetmann, and R. D. Elliot. Eightieth meeting of the Wilson Ornithological Society, Waterville, ME. 11 June 1999 and 23rd Waterbird Society Annual Meeting, Grado, Italy. 9 November 1999 (poster).

Population trends of gulls and Arctic Terns nesting in the Belcher Islands, Nunavut. Gilchrist, H. G., and G. J. Robertson. 1999. Arctic 52: 325-331.

Pre-hatch brood amalgamation in Common Eiders: why do eiders adopt eggs? Robertson, G. J. 114th meeting of the AOU, Boise, ID. 15 August 1996 (poster).

Radar and visual observations of the moult migration of common scoter within eastern Baltic Zalakevicius, M. and Jacoby, V., 1992, , IWRB Seaduck Bull. 1:51..

Razorbill population trends in the Gannet Islands, Labrador, and the effects of Arctic Fox presence on breeding numbers. Elliot, R.D., and G. J. Robertson. Atlantic Society of Fish and Wildlife Biologists: annual meeting. 29 September 1999 and ACWERN annual meeting, Brier Island, NS. 16 October 1999 (oral presentation by R.D. Elliot).

Razorbill surveys in the Gannet Islands, 1983-1998. Robertson, G. J., R. D. Elliot and I. L. Jones. ACWERN annual meeting, St. John‚s, NF. 30 October 1998 (oral presentation).

A reestimation of western Palearctic wintering seaduck numbers from the Baltic

Pihl S. and Laursen, K., 1996, Sea 1993 survey, Game Wildl. 13:191-199..

Responses of lesser snow geese to artificially induced hatching asynchrony and increased clutch size. Robertson, G. J., M. A. Owen, and R. F. Rockwell. 1995. Auk 112: 790-794.

 

 

Seabird and seaduck movement through the Northumberland Strait

MacKinnon, C. M., Daury, R. W., and Hicks, R. J., 1991, , 1990, Can. Wildl. Serv. Tech. Rep. 130..

Sea ducks and the annual cycle. Robertson, G. J. Symposium Plenary Paper. 23rd Waterbird Society Annual Meeting, Grado, Italy. 9 November 1999 (oral presentation).

Seaducks: a time for action

Petersen, M. R. and Hogan, M. E., 1996, , Proc. Int. Waterfowl Symp. 7:62-67..

Sex-biased winter philopatry in Harlequin Ducks: are waterfowl an exception to the rule? Robertson, G. J. 114th meeting of the AOU, Boise, ID. 14 August 1996 (oral presentation).

Sex-biased winter philopatry in Harlequin Ducks: are waterfowl really an exception to the rule? GREGORY J. ROBERTSON, Dept. of Biol. Sci., Simon Fraser Univ., Burnaby, BC.

ABSTRACT

Many birds species exhibit a resource based mating system where males defend breeding territories. This mating system is thought to have lead to male-biased philopatry as male birds are better able to defend familiar territories. In contrast, female waterfowl are more likely than males to return to their breeding grounds. Waterfowl are the exception because males cannot economically defend breeding territories and a mate-defense system has evolved. However, waterfowl pair in the winter. If male waterfowl can

defend winter territories a resource defense mating system may evolve and, consequently, male-biased philopatry to the wintering grounds. Since August 1994 I have studied a small population of wintering Harlequin Ducks (Histrionicus histrionicus) in coastal southwestern British Columbia. Locally, a total of 122 individuals have been caught during the wing molt and marked with individually identifiable tarsal leg bands. Weekly surveys were conducted to assess population size, sex ratio, age structure and as

many bands as possible were read. The local population size and sex ratio fluctuated considerably over the two winter seasons. An influx of young males and unpaired males occurred in April of each year, before departure to the breeding grounds. Males moved around the study site more than females. Unpaired males moved around the study site more than paired males. Return rates from one season to the next were high (males: 72%, females: 66%) and did not differ between the sexes. Pairing occurred early in the winter

(November) and pair re- formation occurred in 4 pairs where both members returned to the study area. Harlequin Ducks appear to have a mate-defense mating system and male-biased winter philopatry would not be expected.

Sources of egg size variation in eiders. Robertson, G. J Pacific Ecology Conference, Oregon Institute of Marine Biology, Coos Bay, OR. 26 February 1995 (oral presentation).

Sources of intraclutch egg size variation in the Common Tern Moore, D. J. and G. J. Robertson.. Society of Canadian Ornithologists, Annual Meeting, Vancouver, BC. 4 August 1998 (oral presentation by D. Moore).

Spacing patterns, mating system, and winter philopatry in Harlequin Ducks. Robertson, G. J., F. Cooke, R. I. Goudie and W. S. Boyd. in press. Auk

The status of the harlequin duck (Histrionicus histrionicus) in eastern North America

Goudie, R. I., 1991, , Can. Wildl. Serv., St. John's, Newfoundland. 59 pp.

Status of harlequin ducks in North America

Harlequin Duck Working Group., 1993, , Idaho Dep. Fish and Game, Boise. 83pp..

Status of the harlequin duck, Histrionicus histrionicus, in the Northwest Territories

Fournier, M. A. and Bromley, R. G., 1996, , Can. Field-Nat. 110:638-641..

Status of seaducks in eastern North America U.S.Fish and Wildlife Service, 1993, ,

U.S. Fish Wildl. Serv., Office of Migratory Bird Manage., Laurel, Md

Survival, emigration, and winter population structure of Harlequin Ducks.

Cooke, F., G. J. Robertson, C. M. Smith, R. I. Goudie and W. S. Boyd. 2000. Condor 102: 137-144.

The status of sea ducks in the north Pacific rim: toward their conservation and management, Goudie, R. I., Brault, S., Conant, B., Kondratyev, A. V., Petersen, M. R., and Vermeer, K., 1994, Trans. N. Am. Wildl. Nat. Resour. Conf. 59:27-49..

A summary of current knowledge on the distribution and abundance of moulting seaducks in the coastal waters of British Columbia,

Savard, J.-P. L., 1988, Can. Wildl. Serv. Tech. Rep. 45..

Survival estimates for Harlequin Ducks from wintering ground studies.

Cooke, F. and G. J. Robertson Harlequin Duck Working Group, 4th Biennial Symposium, Newport, Oregon. 2 March 1998. (oral presentation by F. Cooke).

Temporal changes in the anti-predator flocking behavior of wintering shorebirds Cullen, S. A., and G. J. Robertson. 1999.. Waterbirds 22: 156-159.

Time-activity budgets of Harlequin Ducks moulting in the Gannet Islands, Labrador. Adams, P.A., G.J. Robertson and I.L. Jones. 23rd Waterbird Society Annual Meeting, Grado, Italy. 9 November 1999 (poster).

Time budget of surf scoter (Melanitta perspicillata) broods, Savard, J.-P. L. Reed A.,

Aubry, Y., Morrier, A., Lesage, L., and Reed, E., 1998, In I. Goudie and M. Peterson, eds. Proceedings of the syposium on behavioral ecology of seaducks. Can Wildl. Serv, Ottawa, Ont..

The timing of arrival and moult chronology of harlequin ducks,

Robertson, G. J., Cooke, F., and Boyd, W. S., 1998, Wildfowl 48:147-155..

Timing of pairing and molt chronology of Harlequin Ducks. Robertson, G. J., B. Gowans, and F. Cooke. First North American Duck Symposium and Workshop, Baton Rouge, LA. 13 February 1997 (poster).

The timing of pair formation in harlequin ducks,

Robertson, G. J., Cooke, F., Goudie, R. I., and Boyd, W. S., 1998, Condor 100:551-555..

The waterfowl of the world Vol Three Eiders pochards perching ducks scoters, golden-eyes and mergansers stiff-tailed ducks

Delacour, J., 1959, , Country Life Ltd., London, U.K. 270pp..

 

Winter Philopatry In Harlequin Ducks: Implications For Their Conservation In The Strait Of Georgia, BC.

ROBERTSON, G.J., F. COOKE, Department of Biological Sciences, Simon Fraser

University, Burnaby BC and R. I. GOUDIE, and BOYD, W.S.Pacific Wildlife ABSTRACT

Research Centre, Canadian Wildlife Service, Delta, BC, Canada

Habitat use and requirements for wintering birds has only recently received attention compared to breeding habitat use and requirements. For waterfowl, quality wintering habitat is important for not only surviving the winter period, but for courtship and pair bond formation as well. Harlequin Ducks are a small sea duck that nest on mountain streams and winter on coastal rocky shores. We have been marking a portion of the Harlequin Duck population in the Strait of Georgia with small tarsal leg bands annual ly

since 1993. One of our main objectives is to estimate the rate at which individuals utilize the same wintering sites between years. A focal population at White Rock, BC consisting of about 100 individuals has been intensively studied to achieve this ob jective. Over half and up to 3/4 of the individuals marked in one year returned to the site in a later year. If

both members of a pair return to the same wintering grounds they will re-unite. Limited data for younger age classes suggest that they have low er return rates. This tendency for individuals to return to the same site year after year has significant conservation implications for these birds. One, is that local populations may be genetically isolated reducing the effective population size. Second ly, major local habitat degredation may result in the loss of local populations with no subsequent recolonization even if the

habitat is restored. Thirdly, chronic disturbances and minor habitat degredation may cause birds to lose body condition which may result in poor productivity in the following breeding effort. Harlequin Ducks are currently listed as endangered on the east coast of North America, as such, they are known to be a very sensitive species. Threats to this species and its' habitat should be considered very real conservation concerns.

Winter philopatry in migratory waterfowl.

Robertson, G. J., and F. Cooke. 1999. Auk 116: 20-34.

 

ABSTRACT.--PHILOPATRY IN MIGRATORY SPECIES CAN APPLY TO ANY LOCATION USED DURING THE ANNUAL CYCLE. THE DEGREE OF PHILOPATRY INFLUENCES THE GENETIC STRUCTURE OF POPULATIONS, BUT ONLY AT THE STAGE OF THE ANNUAL CYCLE WHEN PAIR FORMATION AND GENE EXCHANGE OCCUR. Because pair formation in birds typically occurs during the breeding season, most studies have focused on breeding-site philopatry. Waterfowl (Anseriformes) are an important exception to this pattern because pair formation often occurs during the winter months. Yet, surprisingly few studies have examined winter philopatry in waterfowl. To serve as an impetus for future research, we summarize published information on winter philopatry in waterfowl and examine these patterns in light of current hypotheses proposed to explain philopatric behavior. Our analyses indicate that geese, swans, and sea ducks show high levels of winter philopatry, with homing rates varying between 49 and 98% in small study areas. In contrast, return rates (0 to 20%) and homing rates (35 to 85%) to large study areas probably are comparatively lower for dabbling ducks and pochards. Unfortunately, detailed comparisons among groups are hindered by variation in the scale at which philopatric behavior is evaluated (ranging from 2 to 105 km2), and by confounding of return rates with homing rates. Future studies of winter philopatry would benefit by the adoption of a more standardized methodology. Many of the hypotheses proposed to explain breeding philopatry apply equally well to winter philopatry. In particular, both genetic and ecological mechanisms may play a role in the evolution of philopatry to the wintering ground. Additional field studies are needed to test these hypotheses, and we suggest future directions for a more detailed examination of this neglected area of research. Received 9 September 1996, accepted 28 April 1998.

Associate Editor: John M. Eadie

Winter philopatry in Harlequin Ducks: implications for their conservation in the Strait of Georgia, BC. Robertson, G. J., F. Cooke, R. I. Goudie, W. S. Boyd. Society for Conservation Biology, Annual Meeting 1997, Victoria, BC. 7 June 1997 (oral presentation).

 

Winter Philopatry In Harlequin Ducks: Implications For Their Conservation In The Strait Of Georgia, BC.

ROBERTSON, G.J., F. COOKE, Department of Biological Sciences, Simon Fraser

University, Burnaby BC and R. I. GOUDIE, and BOYD, W.S.Pacific Wildlife

Research Centre, Canadian Wildlife Service, Delta, BC, Canada

ABSTRACT

Habitat use and requirements for wintering birds has only recently received attention compared to breeding habitat use and requirements. For waterfowl, quality wintering habitat is important for not only surviving the winter period, but for courtship and pair bond formation as well. Harlequin Ducks are a small sea duck that nest on mountain streams and winter on coastal rocky shores. We have been marking a portion of the Harlequin Duck population in the Strait of Georgia with small tarsal leg bands annual ly

since 1993. One of our main objectives is to estimate the rate at which individuals utilize the same wintering sites between years. A focal population at White Rock, BC consisting of about 100 individuals has been intensively studied to achieve this ob jective. Over half and up to 3/4 of the individuals marked in one year returned to the site in a later year. If

both members of a pair return to the same wintering grounds they will re-unite. Limited data for younger age classes suggest that they have low er return rates. This tendency for individuals to return to the same site year after year has significant conservation implications for these birds. One, is that local populations may be genetically isolated reducing the effective population size. Second ly, major local habitat degredation may result in the loss of local populations with no subsequent recolonization even if the

habitat is restored. Thirdly, chronic disturbances and minor habitat degredation may cause birds to lose body condition which may result in poor productivity in the following breeding effort. Harlequin Ducks are currently listed as endangered on the east coast of North America, as such, they are known to be a very sensitive species. Threats to this species and its' habitat should be considered very real conservation concerns.

 

Within-season moulting and wintering philopatry in Harlequin ducks.

Robertson, G. J. F. Cooke, and R. I. Goudie. Pacific Seabird Group/Colonial Waterbird Society Joint Conference, Victoria, BC. 9 November 1995 (oral presentation).

Within-season moulting and wintering philopatry in Harlequin ducks. Robertson, G. J. IWWR student/staff Symposium, Oak Hammock, Manitoba. 24 August 1995 (oral presentation).

Within-year fidelity of Harlequin Ducks to a moulting and wintering area

Gregory J. Robertson, Fred Cooke, R. Ian Goudie and W. Sean Boyd

Foraging strategies and habitat use of sea ducks breeding in northeast Russia by Alexander V. Kondratyev

Within year fidelity of Harlequin Ducks to a moulting and wintering area. Robertson, G. J., F. Cooke, R. I. Goudie, and W. S. Boyd. 1999. Pages 45-51 in Behaviour and ecology of sea ducks. (R. I. Goudie, M. R. Petersen and G. J. Robertson,  eds.). Canadian Wildlife Service, Occasional Paper Series No. 100, Ottawa.


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