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CHAPTER II STAGE ONE MONITORING • was determined from record searches and field observations. The com- position and relative abundance of fish populations were also determined. Details of methodology are presented in wildlife monitoring reports (CDOW 1982 and 1984b). Wildlife habitat types were delineated by sampling specific vegeta- tive parameters and by mapping habitats according to type. Changes were documented by preproject and postproject aerial photography. Bird popu- lations were studied by monitoring populations in different habitats through the use of roadside and absolute counts and Emlen transects. Additionally, pheasants were monitored by conducting spring crow counts, summer brood counts, and fall age class studies. Waterfowl nesting suc- cess was sampled, and winter resting areas in the study area were moni- tored. Live trap grids were used to determine small mammal densities and diversity and their relative abundance in agricultural areas and population along irrigation canals and laterals. Aquatic habitat studies included invertebrate and fish sampling and water quality analyses. Several immediate effects of construction were documented. Replac- ing earth laterals with pipe resulted in natural vegetation being cleared on about 200 acres,; this vegetation has not returned because of reduced seepage, expanded fields, and other factors. About 75 percent of the cottonwood trees located along the laterals were either cleared during construction or are expected to be lost. Marsh areas, shrublands, and tamarisk areas in Stage One sampling sites following construction de- clined 6 percent, 8 percent, and 2 percent, respectively. Marshes adja- cent to the lined canal began drying up immediately following construc- tion. Croplands actually increased, but edge vegetation around cropland declined by 53 percent. Vegetation has returned to a large portion of the cross-drainage system and construction material areas, a regrowth aided in some places by reseeding and overall by several seasons of above normal precipita- tion. Erosion in a small portion of cleared areas has been a problem and is related to steep slopes of cross-drainage dikes and dams and low vegetation density. As could be expected, wildlife use of the construction rights-of- way declined. Following construction, bird density along lateral rights- of-way declined 60 percent. In the marsh area monitored along the lined portion of the canal, the population of breeding birds declined 36 per- cent; numbers of small mammals also declined. Other habitats showed little change. In some lateral areas, weeds returned the following season and were used for feeding by birds and small mammals. Between 1981 and 1984, 21 deer and 2 elk were rescued from the lined portion of the canal, and 7 deer are known to have drowned. A high percentage of animals were rescued becau se construction or wildlife agency workers we re in the area; but under normal conditions, a much lower rescue rate would occur. In contrast, there were no known losses in earthen canals in the area during this same period. Deer and elk 14