5) Estimated Losses Due t^ tii£ Project 



- Quantitative loss estimates - none were developed due to 

 lack of population data. 



- Qualitative loss estimates - 



Canada goose - moderate to high 



American wigeon - negligible 



Mallard - moderate 



Wood duck - low to moderate 



Barrow's goldeneye - low 



Coirmon goldeneye - moderate 



Harlequin duck - low to moderate 



6) Deriv£cion of Loss Estimates 



Quantitative loss estimates were not developed due to the lack 

 of population or density data prior to construction of the Libby 

 Dam project. Qualitative population levels (Table 4) were used in 

 the development of the qualitative loss estimates. 



Qualitative loss estimates were developed based on: 1) the 

 known distribution and habitat requirements of the species assumed 

 to occur at the site; 2) limited description of habitats in the 

 pool area prior to inundation; and 3) an assessment of the regional 

 importance of the waterfowl populations at the site. The latter 

 assessment was based on the professional opinion of biologists 

 involved with this project, and available data from elsewhere in 

 the region. 



Impacts to the Canada goose population were estimated to be 

 moderate to high based on the probable pre-project population level 

 of this species, and a loss of the majority of suitable nesting 

 sites and brood rearing habitat along the full length of the inun- 

 dated river (criteria (a) through (d), page 9). Though suitable 

 nesting sites - snags, stumps, and trees - are present along the 

 reservoir, brood habitat is lacking. 



Qualitative loss estimates for mallard and American wigeon 

 were moderate and negligible, respectively. Ihese losses were 

 based on the loss of resting and brood rearing habitat combined 

 with the pre-project population levels (criteria (a) through (c), 

 page 9). The fluctuating water levels limit the availability of 

 suitable brood-rearing and feeding habitats for these species. 



A number of cavity-nesting waterfowl species lost preferred 

 nesting and brood habitat when riparian areas (nesting sites) 

 adjacent to suitable brood habitat were lost when the project was 

 constructed. "Itie 3 cavity nesting species considered on the target 

 species list were assessed various degrees of impact based on their 

 pre-project population sizes (Table 4). Common goldeneye, wood 



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