(1987) found that harlequin ducks began to arrive on the breeding 

 grounds during the first week of May. Pairs commonly were 

 observed on the streams until the onset of incubation in late 

 June or the first week of July. At this time drakes and unpaired 

 hens left for the coast while nesting hens remained secluded on 

 the nest. Broods did not begin to appear on the streams until 

 mid-July or early August. Hens and broods remained on the 

 breeding streams until mid-September after which, they also 

 departed for the coast. This chronology is consistent with the 

 observations of Kuchel (1977) and Dzinbal (1982). 



Wallen (1987) characterized harlequin duck breeding habitat 

 in GTNP as low gradient (<3 degrees) mountain streams with 

 meandering channels, dense perennial shrubs on the banks, high 

 water quality, and little or no human disturbance. He also found 

 that harlequins appeared to prefer stream sections that had >3 

 midstream loafing sites per 10 m and avoided sections where both 

 banks approached the stream at >45 degree angle (i.e. bedrock 

 canyons) . 



In Iceland, harlequin ducks tended to nest in dense shrubs 

 on river islands or in the cracks and crevices formed by large 

 Ic^va blocks along stream banks, again under dense shrubs 

 (Bengston 1966, 1972). No nest sites have been found during 

 studies in North America but probable nesting habitat has been 

 inferred from observations of recently hatched broods. Kuchel 

 (1977) considered dense shrubs surrounding beaver ponds or 

 abandoned meanders to provide harlequin nesting habitat in GNP. 



