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Wildlife Resources Assessment Cemex "C" Pit and CKD Disposal Site Page 5 I 1 - _ 4.0 INFORMATION REVIEW This section reviews previous studies in and near the analysis area that included this report author as a participant. Participation ranged from project manager, principal investigator to field assistant. 4.1 Previous On Site Wildlife Studies The following studies have been conducted and adjacent areas. within the analysis area and include "C" Pit Dowe Flats Winter Raptor Study. Boulder County. Colorado: 1993-1998 (Thompson et al. 1999) This study was a voluntary commitment of Southdown, Inc, as a part of the Boulder County Special Use Permit for the Dowe Flats mine. All of the Lyons Quarry and much of the adjacent area was included in the study area. Study goals were to: Document the relationship between wintering raptors and the local prairie dog community during baseline and treatment phases of mining at Dowe Flats and during comparable conditions at the Lyons Quarry to: A. assess compatibility of raptors/prairie dogs with mining and reclamation, and B. to better predict project effects on raptor/prairie dog use of Dowe Flats. 2. Contribute study results to the development of a comprehensive, long-term raptor conservation strategy for Boulder County. The study included determining prairie dog population size and distribution in the study area at three times during each year: 1) at peak population in late May and early June, 2) at the beginning of winter raptor residency (November) and 3) at the end of winter raptor residency (early April). Population data was subject to statistical analysis. Lagomorph populations were also monitored, but these data were not considered central to the mission of the study. A winter raptor sampling period was established from November 1 to April 14 of each season. Simultaneous, systematic, standardized crepuscular and early morning surveys were conducted approximately every 14 days. All raptors detected during surveys were recorded, although only data on the bald eagle, ferruginous hawk and golden eagle, species that feed heavily on prairie dogs, were included in study results. During each survey raptors were identified and locations of hunting perches, nocturnal roosts, and flights were mapped. Proximity of roosts and hunting perches to any source of human disturbance, mine related or otherwise, were mapped and measured. Structural roost and perch characteristics were mapped and noted for each observation. The association between raptors and prairie dogs was evaluated by graphically comparing minimum numbers of raptors and prairie dog population. Raptor responses to potentially disturbing mining and other human activities were recorded on forms during each survey. Predisturbance raptor activities and potential disturbances were categorized and included in project analysis, as was disturbance duration and repetition. This analysis included blasting in mine pits. The study was conducted over five years and cost in excess of