The Atlantic population has undergone and is continuing to undergo significant declines 

 (Harlequin Duck Working Group 1993). Trends in the Greenland and Iceland populations are 

 unknown. 



POPULATION REGULATION -- 



A simple model using "guesstimates" for values of survival and fecundity was developed / 

 by Goudie and Breault (1994). They estimated that at 85% adult survival, the population would j Jc 

 grow at a rate of 6%/year. Simulations indicate that the model was most affected by adult ^ 



survival; an increase of 3% in mortality may not be sustainable over the long term (Goudie and / 

 Breault 1994). _/ 



CONSERVATTON AND MANAGEMENT 



EFFECTS OF HUMAN ACTIVITY ON HARLEQUIN DUCK POPULATIONS, 

 REPRODUCTION, AND BEHAVIOR 



Disturbance on the breeding grounds. On and near shore. Kuchel (1977) found that 

 broods less than 4 weeks old avoided areas with human access and selected areas that were 

 distant from access or inaccessible (p<0.05) on McDonald Creek in Glacier National Park. This 

 was not true of adults during May and early June when fewer park visitors were present. More 

 recently, Ashley (1994) found that Harlequins used inaccessible areas in greater proportions than 

 the availability of those areas, though not significantly so; this data is conservative in that 

 surveys took place in the early morning prior to the vast majority of visitor use. Most Harlequins 

 left accessible stream reaches when visitor use reached greater than minimal levels. Ashley 

 (1994) found that males were displaced by human activity to a greater extent than were females, 

 which he speculated could be due to any or all of three reasons. First, females were likely bom 

 in Glacier National Park with its many visitors, and were therefore more habituated to humans 

 than were males, which were likely bom at other locations. Second, females spend more time 

 each year on McDonald Creek during higher visitation periods than do males, and may thus be 

 more habituated to human contact. Third, females are more cryptically colored and therefore less 

 likely to attract casual visitor attention. 



On the Rocky Mountain Front in Montana, only 15% of sightings were in areas that were 

 inaccessible (>50 m from established areas of human activity, not accessible by trail) (Diamond 

 and Finnegan 1993). Of the accessible areas, 51% were >50 m from a trail, 21% were 10-50 m 

 from a trail and 13%i were <10 m from a trail; it should be noted that >90%) of this area is 

 roadless. Visitor use is highest along the South Fork Sun River: 500 people/month use the trail 

 in July and August (Diamond and Finnegan 1993). 



In Grand Teton National Park, Wyoming, 95% of Harlequin observations were in 

 backcovmtry areas, accessible only by trail (Wallen 1987). Within the backcountry however. 

 Harlequins used areas with moderate (5-9 people/day) to heavy (>10 people/day) human use 

 more than they used areas with less human use; Wallen (1987) suggested that these observations 

 may have been the result of the presence of many high gradient, inaccessible stream reaches 

 which lacked the habitat features preferred by Harlequins. 



In Yellowstone National Park, a three-year study was done to assess visitor impacts to 

 Harlequin use at LeHardy Rapids, where it appeared that duck use had decreased due to high 

 visitor use (McEneaney 1994). The area was closed to visitors from 1 May - 7 June 1991-1993, 

 and Harlequin Duck use increased; however, a historical nest site in the immediate vicinity was 



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