preferred feeding sites which are characterized by laminar rather than 

 turbulent flow (Hynes 1970). Harlequin ducks nest in tree cavities, 

 fissures in rocks, or on the ground near turbulent water (Peterson 1961, 

 Bellrose 1976, Bengtson 1966); the majority of broods hatch during the 

 first week of July and do not feed in fast water for two weeks. A 

 search of the Falls area on June 29-30, 1978 failed to reveal either 

 adult birds or young. 



Fewer harlequin ducks were present at the Falls in 1979 than in 

 1978; only 8 or 9 observations were made during the report period. The 

 first individual encountered in 1979, a lone male, was seen at the head 

 of the Falls on April 18. On April 21, 1979, a male was seen below the 

 footbridge and another (possibly the same individual) on rocks just 

 above the Falls. According to Kuchel (1976), non-breeding males arrive 

 in Montana in mid-April, two or three weeks before the rest of the 

 population; it is therefore likely that these April observations represent 

 non-breeding individuals. Harlequins were next seen on June 13, 1979, 

 when a female was seen swimming along the shoreline near the bend in the 

 river between sections G and H. It was only observed for a few minutes 

 before it disappeared among the rocks. A male was also seen flying back 

 and forth in this same area, but there was no indication that the two 

 were paired (Smith 1979). An intensive search was made of the Falls 

 area for harlequins on June 13-14 and 27-30, but no birds were seen. 

 Two females were seen together at the head of the Falls on July 31 and 

 again on August 1, 1979; a careful search of river section G-L for 

 broods on August 1 failed to yield additional observations. Kuchel 

 (1976) reports that, in Glacier Park, pairs dissolve and all males 

 usually leave the breeding grounds in mid-June. Non-breeding females 

 may depart as the final males leave the area, while females with broods 

 remain until August. While it is therefore possible that the June 13, 



1979 observations represent a nesting pair, and the females seen in 

 August were breeding individuals which had lost either nests or broods, 

 it is also likely that the 1979 Falls area population is simply a non- 

 breeding aggregation, as described by Bengtson (1972). Breeding popu- 

 lations may occur in larger tributaries of the Kootenai River (such as 

 China Creek), although none have yet been reported. The nearest known 

 breeding population is at Grave Creek, a tributary of Fortine Creek 

 (Weydemeyer 1979). 



Common Merganser . Common mergansers were observed during all 

 seasons, and were observed more universally along the river than any 

 other duck species. They were seen on the river from near the city 

 limits of Libby to near Throops Lake (D). Second only to harlequin 

 ducks, common mergansers used the fast water of the Falls for feeding 

 and security (I, J, L). Common mergansers nest in cavities of deciduous 

 trees, usually near water. At least two broods (probably creches) 

 having an average brood size of 11.5 were seen in 1978 between Williams 

 Creek and China Creek (N and Z). A brood of 7 was seen on June 27 and 28, 

 1979, in river section M and P. 



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