SUMMARY 



Harlequin duck surveys were conducted on 12 streams in the 

 Gallatin National Forest and two streams in the Custer National 

 Forest during the period May - August, 1990. Most stream sections 

 were surveyed at least twice, once during the early part of the 

 season and a second time later in the season. Survey sections were 

 selected by size and gradient. Harlequin ducks were observed only 

 on a short section of the Boulder River on three separate days. A 

 total of 18 harlequins were seen but these probably represent only 

 15 individual ducks as some probably were seen more than once. The 

 breakdown of observations is as follows: 19 May - one pair; 6 June 

 - five adult males, one pair, and one adult female; 23 August - 

 eight individuals of undetermined sex and age. Behavioral 

 observations included swimming, loafing, preening, feeding, and 

 mating. The number of harlequin observations was too small to make 

 meaningful comparisons or predictions of habitat use patterns. The 

 observations that were made compare favorably with results obtained 

 from a study in Grand Teton National Park. In general, harlequins 

 appear to prefer streams of low gradient (<3 degrees) with gently 

 sloping banks (<45 degrees) which have a dense cover of perennial 

 shrubs. Several streams in the study area appeared to offer 

 suitable habitat that was not being used by harlequins. However, 

 because of their size, color (especially hens and young) , and 

 habitat preference it is difficult to spot harlequins in the field. 

 Although the survey effort was very thorough it is possible that 

 some harlequins may have been overlooked on some streams. If other 

 populations do exist in this area they are likely to be small and 

 transitory. Additional survey work in this area will be dependent 

 on the needs of management agencies. Further study on harlequin 

 duck biology and habitat needs would be more profitable in areas 

 with higher harlequin duck densities. 



