2. Stressor-response Relationships. 
Although information currently exists on the toxicity of mercury to several bird species, none of 
the tests were conducted in such a way that dose-response relationships can be estimated and 
none were conducted with carnivorous species. In fact, testing of avian reproduction effects is 
rarely done with the intent of defining dose-response relationships for population-related 
endpoints. Development of dose-response relationships would include: 
• A controlled dosing study to determine dose-response relationships for methyl mercury 
effects on survival and fecundity of American kestrels {Falco sparverius). Husbandry 
methods for breeding piscivorous birds in captivity generally have not been developed, 
but the kestrel has a long history of successful breeding under laboratory test conditions. 
This study is currently being conducted in cooperation with USGS Patuxent Wildlife 
Research Center and NCEA. 
• Empirical development, from existing field monitoring data, of stressor-response 
relationships for measures of productivity for other types of stressors, including habitat 
impairment, human disturbance, and lake acidification. It will be more difficult to show a 
relationship of these stressors to adult survival. 
3. Interspecies Extrapolation. 
Extrapolation methods are needed for estimating toxicity in untested species from tested species, 
from laboratory tests to free-flying wildlife, and across media. Extrapolation of toxicity 
information includes: 
• Development of PBTK/TD models for methyl mercuiy in kestrels for predicting effects in 
loons and other piscivorous birds. Mercury residue information from studies with 
kestrels will be used to develop residue-response relationships sensitive to the duration of 
exposure. The PBTK/TD model then will be used to predict the movement and effects of 
methyl Hg in other species. This model will be developed through a cooperative project 
with USGS (Patuxent) and NCEA. 
• Empirical extrapolation methods based on a synthesis of existing toxicity databases. 
These methods estimate a distribution of sensitivity across tested species, but are poor 
predictors of where a specific species would fall in that distribution. This work would 
build on existing syntheses projects by including new data from the kestrel studies and 
other published data. 
4. Population Matrix Models. 
Age-class matrix models will be used to organize information on the population dynamics of 
loons and other piscivorous birds. Development of matrix models would include: 
• Integration of life history information including adult and juvenile survival, fecundity, 
immigration and emigration rates, and density dependent factors into the model 
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