New Releases by Paul Clark

False-positive and false-negative values were calculated for five different designs of the trend test and it was demonstrated that a design suggested by Portier and Hoel in 1984 for a different problem produced the lowest false-positive and false-negative rates when applied to historical spontaneous tumor rate data for Fischer Rats.

Includes a section on life skills.

Effects of grazing by cattle in winter and mowing of hay in late summer on the nesting ecology of ducks in southeastern Oregon were studied from March through August of 1974 and 1975. A 650 ha study area was divided into 3 units and 3 patterns of management designed to produce differing amounts of residual cover were employed; management of each unit was changed between 1974 and 1975. The 3 patterns of management were: (1)unrestricted mowing and grazing prior to the waterfowl nesting season,(2) partial mowing but no grazing prior to the nesting season, and (3)neither mowing nor grazing prior to the nesting season. A total of 333 duck nests were found on the study area during 1974 and 1975. Mallards (Anas platyrhynchos), cinnamon teal (Anas cyanoptera) and gadwalls (Anas strepera) were the most common nesting species, constituting 91 percent of the nests studied. The remaining 9 percent were nests of shovelers (Anas clypeata), American wigeon (Anas americana), green-winged teal (Ana.