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 (adults = 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% being within 

 10 m of activity sites (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 m from a trail 

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

 the hen from 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 e/ fl/. 1993). 



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

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

 during that period. Harlequin Duck numbers have decreased substantially (Clarkson 1992, Hunt 

 1993). It was felt that disturbance was likely the cause of the decline, and recommendations 

 were therefore made to revise methods of controlling rafting including: closing particular river 

 reaches to boating and to other human activity; and not issuing new business licenses/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 had been 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. 

 Harlequins were found to avoid 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 themselves while moving 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, where fishing was not observed (Wallen 1987). 



In boats. Prior to significant raft and canoe use on rivers in Jasper and Banff, Holroyd 

 (1979) warned of the potential negative effects of intensive river use on Harlequin Ducks. Since 

 that time, commercial Whitewater rafting in Jasper National Park has frequently exposed pre- 

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

 commercial trips took place there in 1986, but 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 the 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). Birds usually took flight if a raft was on a collision course with a bird, was 

 within 1-15 m of a bird, or if the raft crew was acting "boisterously" as they passed the duck 

 (Clarkson 1992). Hunt (1993) recommended closure of the river to rafting in an attempt to 

 restore historic population levels of Harlequins. He listed other less commercially disruptive 

 actions which could possibly help stem the decline in Harlequins, including: 1) reducing the 



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