This layer shows critical winter and summer ranges, fall holding areas, and fawning grounds for deer (Odocoileus hemionus) in CDFG Region 1 (Shasta, Tehama, Lassen, Modoc, Siskiyou, Trinity, and Humboldt Counties). CDFG Wildlife Biologists compiled these data in the 1970s as part of a project to identify Areas of Significant Biological Importance (Jones and Stokes 1979). This project required unit biologists to delineate natural resource boundaries and features on USGS 7.5 and 15 quadrangle maps. Deer range designations were based on biotelemetry studies, personal knowledge, and predicted use of habitats. These data were subsequently digitized to produce this dataset. The purpose of this dataset is to provide general information on the distribution of important deer ranges in Northern California. Range designations may not be current due to anthropogenic impacts or lack of data regarding the locations of seasonal ranges used by deer. CDFG should be consulted for current site-specific information on the designation or usage of seasonal ranges by deer. These maps have not been updated using current GPS techniques and may not include important corridors, reproductive areas, or other ranges important to deer populations. Critical deer winter range can include corridors essential for movement, staging areas where deer temporarily congregate, habitats containing high quality winter forage, or other elements important to the survival of deer in winter. Winter ranges are generally at lower elevations and are far less abundant than summer ranges making them vulnerable to human impacts and often a limiting factor in populations. Deer from different summer ranges may share a common winter range where breeding typically occurs. This mixing of genes on winter ranges contributes to genetically diverse and healthy populations. Critical summer range occurs generally at higher elevations, but can be similar to fall or winter ranges when deer are non-migratory. These ranges are vital to population productivity by providing habitats for parturition and rearing and forage for replenishing nutritional reserves. Summer ranges may be occupied by deer from several distinct winter ranges.. Fall holding areas are used by deer when transitioning to winter ranges. These areas can also be used in mild winters where adequate forage is available and escape from deepening snows is unnecessary. Fawning areas are critical to population productivity. They are generally located within summer ranges but can occur throughout the home ranges of non-migratory deer. Fawning areas are often linked to meadow complexes or riparian communities where adequate cover can hide newborn fawns and herbaceous forage can replenish the nutritional demands of lactation.