Annual and lifetime reproductive success. Reproductive success was poor in Montana 

 in 1995, with one of the lowest numbers of broods and young per female recorded since 1989 

 (Table 5, 6). In Montana during 1974-1975 and 1989-1995, annual numbers of ducklings 

 fledged per adult female averaged 1.39 and ranged from 0.13-3.15 (n=305 adult females) (Table 

 6). Brood size (lib to fledging) averaged 3.59 and ranged from 2.00 - 5.86 (n=l 18 broods) 

 (Table 6). 



Broods ranged from 1-6 in Oregon and averaged 2.7 (n=26) (Thompson et al. 1993, 

 1994). These sightings, however, were spread throughout the breeding season and therefore 

 should not be considered the same as numbers fledged. 



In Idaho, number of ducklings fledged per adult female ranged from 0.7 - 1 .3 and 

 averaged 1.2 (n=14); number of females producing broods was 29% in 1990 (Cassirer and 

 Groves 1991, 1994). Average brood size was 3.4 (range 1-7) in Idaho (n=24) (Cassirer and 

 Groves 1991). 



In British Columbia, 41 broods of all ages ranged in size from 1 - 10 (1 Y-3, 2Y-3, 3Y-5, 

 4Y-1 1, 5Y-14, 6Y-2, 7Y-1, 8Y-1, lOY-1); the brood with 10 young was apparently from a single 

 female (Campbell et al. 1990). 



In Alaska, numbers of young per breeding female and per aduh female were respectively 

 1.5 and 0.8 in 1979, and 0.6 and 0.3 in 1980; patagial tags on adults appeared to have caused 

 poor reproductive success (Dzinbal 1982). Non-breeding frequency of females was 47% in 1979 

 and 50% in 1980 (Dzinbal 1982). 



In Iceland, 1.73 (85:49) and 2.43 (120:49) young per adult female were successfully 

 raised during 1975 and 1976, respectively (Gardarsson 1979). In an increasing population in 

 Iceland, productivity ranged from 0.1 to 3.3 (x = 1.1) ducklings fledged per hen per year over 15 

 years (Gardarsson and Einarsson 1991). These results were similar to those of Bengtson (1972), 

 who reported 0.0 to 3.8 young per adult female on 4 rivers during 4 years. 



Proportion of total females that rear at least one brood to nest-leaving. Harlequin 

 Ducks raise only a single brood each year. The proportion of females successfully raising a 

 brood in a single year varies widely between years. In Montana during 1995, only 23% of 48 

 females successfully raised a brood (Table 5); stream surveys between 1974 and 1995 found that 

 305 females raised 118 broods for an average of 38.7% (range 7-55%) (Table 6). From 

 throughout their range, the percentage of females which successfully raise a brood varies from 7- 

 56% (Bengtson and Ulfstrand 1971, Kuchel 1977, Wallen 1987, Cassirer and Groves 1991, this 

 report). 



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