gradient, inaccessible stream reaches which lacked the habitat features Harlequins preferred. 



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 fiom 1 May - 7 June 1991-1993 

 and Harlequin Duck use increased; a historical nest site in the immediate vicinity was not 

 reoccupied (McEneaney 1994). Beginning in 1995, visitors were to be confined to a boardwalk. 



In Idaho, Harlequin Ducks were typically found at sites more than 50 m from road or trail 

 access (aduhs = 75%, broods = 80%) (Cassirer and Groves 1994). Pair densities there were 

 lowest on streams most accessible to human activity (Cassirer and Groves 1991). In Oregon, 

 duck sightings were much closer to sites with established human activity, with 48% within 10 m 

 (roads 48%, fishing 29%, hiking 19%) (Thompson et al. 1993). 



In Washington, a cavity nest with the opening 2.4 m high was located 1 .3 from a trail (in 

 1991) and within a back country corral (1992); the depth of the nest cavity (61 cm) prevent the 

 hen fi'om seeing outside and hid her from view (Cassirer et al. 1993). Two nest cavities in Idaho 

 however, were located in areas seldom used by humans, about 150 m from logging roads 

 (Cassirer et al. 1993), 



In Jasper National Park, visitor use by hikers, nature tours, fishermen, tourists, and boaters 

 (see below) on Maligne River drainage has increased substantially in the past decade; during that 

 period Harlequin Duck numbers have also decreased substantially (Clarkson 1992, Hunt 1993). It 

 was felt that disturbance was likely the cause of the decline and recommendations were made to 

 revise the method of controlling rafting including: closing particular river reaches to boating and 

 other human activity, and not issuing new business licences/special activity permits which would 

 increase the current level of human activity in the area (Clarkson 1992). 



Within the stream. Cassirer and Groves (1991) reported that 5 of 1 1 streams where Harlequin 

 breeding was reported or confirmed during 1988-1990 were closed to fishing or did not open to 

 fishing until 1 July. 



Wallen (1987) reported that fishing seemed more disruptive to Harlequins than hiking, and 

 they avoided humans on the bank or in the stream bed. Birds would typically swim or dive 

 downstream past people, keeping partially submerged when past and watching behind them as 

 they moved out of the area. Two hens with broods abandoned a section of one creek when 

 fishing pressure increased in August; they moved to a nearby creek which drained into the same 

 lake, and where fishing was not observed (Wallen 1987). 



//; boats. Prior to significant raft and canoe use on rivers in Jasper and Banff, Holroyd (1979) 

 warned of potential negative effects of intensive river use on Harlequin Ducks. Since that time, 

 commercial white-water rafting on the in Jasper National Park has exposed pre-nesting, and 

 perhaps nesting, ducks to frequent disturbance (Clarkson 1992, Hunt 1993). Only six commercial 

 trips took place there in 1986; commercial use increased to over 1500 trips/year by 1990 

 (Clarkson 1992, Hunt 1993). This was significantly correlated with declining Harlequin Duck 

 numbers during the period 1986-1992 (Hunt 1993). Additionally, the mean monthly abundance 

 of Harlequin Ducks is significantly and negatively correlated with number of rafting trips per 

 month (May, June, July) from 1986-92 (Hunt 1993). 



On the Maligne River in 1993, Harlequins were displaced by rafts in 87% of 91 encounters; 

 duck reactions included flying (60%) and swimming (19%) away from the rafts (Clarkson 1992). 



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