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Each spring, thousands of harlequin ducks gather to feast
on herring spawn on Pacific Coast beaches of
Harlequin
ducks gather in large numbers to eat herring spawn before departing for
rivers and streams in the mountains of western North America.
Most harlequin ducks desert the Pacific Coast in April and May for fast flowing mountain streams of western North America where they nest and raise ducklings. They lay eggs in nests in the shrubbery on the stream bank. Males harlequin ducks then return to the coast to moult their flight feathers beginning in June. Females raise the ducklings on a diet of steam insects and small fish in rivers. Once the young can make extended flights, the ducklings accompany the hen to the seashore for the winter. Flocks of flightless ducks are found on small rocky islands and isolated stretches of beach in late July through mid-September. By autumn, both sexes are sporting their new plumages.
References Cooke, F., G.J. Robertson, R.I. Goudie and W.S. Boyd. 1997. Molt and the basic plumage of male Harlequin Ducks. Condor 99:83-90. Hunt, B. and R. Ydenberg. 2000. Harlequins Histrionicus histrionicus in a Rocky Mountain Watershed I: Background and general breeding ecology. Wildfowl 51:155-168. Regehr, H.M., C.M. Smith, B. Arquilla and F. Cooke. 2001. Post-fledging broods of migratory Harlequin Ducks accompany females to wintering areas. Condor 103:408-412. Robertson, G.J., F. Cooke, R.I. Goudie and W.S. Boyd. 1997. The timing of arrival and moult chronology of Harlequin Ducks Histrionicus histrionicus. Wildfowl 48:147-155. Robertson, G. J. F. Cooke, R. I. Goudie and W.S. Boyd. 1998. The timing of pair formation in Harlequin ducks. Condor 100:551-555. Robertson, G.J., F. Cooke, R.I. Goudie and W.S. Boyd. 1998. Moult speed predicts pairing success in male Harlequin Ducks. Anim. Behav. 55:1677-1684. Robertson, G.J., F. Cooke, R.I. Goudie and W.S. Boyd. 1999. Within year-fidelity of Harlequin Ducks to a moulting and wintering area. Occ. Papers CWS :45-51. Robertson, G.J., F. Cooke, R.I. Goudie and W.S. Boyd. 2000. Spacing patterns, mating systems, and winter philopatry in Harlequin Ducks. Auk 117:299-307. Rodway, M. S., H. M. Regehr and F. Cooke. 2003b. Sex and age differences in distribution, abundance, and habitat preferences of wintering Harlequin Ducks: implications for conservation and estimating recruitment rates. Canadian Journal of Zoology 81:492-503. Rodway, M. S., H. M. Regehr, J. Ashley, P. V. Clarkson, R. I. Goudie, De. E. Hay, C. M. Smith and K. G. Wright. 2003a. Aggregative response of Harlequin Ducks to herring spawn in the strait of Georgia, British Columbia. Canadian Journal of Zoology 81:504-514. Rodway, R.S., H.M. Regehr and F. Cooke. In press. Sex and age differences in distribution, abundance, and habitat preferences of wintering Harlequin Ducks: implications for conservation and estimating recruitment. Canadian Journal of Zoology. Rodway, M.S. and F. Cooke. 2001. Effect of food availability on arrival and departure decisions of Harlequin Ducks at diurnal feeding grounds. Condor 103:870-874. Smith, C.M., R.I. Goudie and F. Cooke. 2001. Winter age ratios and the assessment of recruitment of Harlequin Ducks. Waterbirds 24:39-44. Smith, C.M., F. Cooke, G.J. Robertson, R.I. Goudie and W.S. Boyd. 2000. Long-term pair bonds in Harlequin Ducks. Condor 102:201-205. Torres, R., F. Cooke, G.J. Robertson and W.S. Boyd. 2002. Pairing decisions in the Harlequin Duck: costs and benefits. Waterbirds 25:340-347. Wright, K.G., G.J. Robertson and R.I. Goudie. 1998. Evidence of spring staging and migration route of individual breeding Harlequin Ducks, Histrionicus histrionicus, in southern British Columbia. Canadian Field Naturalist 112:518-519.
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