File Geodatabase Feature Class
Tags
Modoc, reproductive sites, northern California, Owens Valley, California, biota, desert, location, Great Basin, territories, Buteo swainsoni, Inyo, observations, Siskiyou, Central Valley, statewide, Swainson's hawk, nests
The database was designed to track the known breeding distribution pattern, history of breeding site occupancy, and trends in land use around nest sites in California. Each unique territory is identified providing the ability to estimate known nest site distribution, potential numbers of nests, and over time, changes in distribution and numbers. The database may be used for development project review where site-specific information and history of occupation could be evaluated to determine how a specific project might impact the hawks, to design project modifications to avoid conflicts, and to support management planning, monitoring and research. DATA ASSUMPTIONS AND LIMITATIONS Significant general assumptions of the data were: 1) Swainson's hawks found spending time in a specific area during the nesting season could be called a territorial, and 2) a site is a location on the landscape that may be occupied by different Swainson's hawks over time. KNOWN CAVEATS OF THE DATA Caveats include: 1) the accuracy of the point representing the territory in any given year is only as accurate as the legal description of that site provided by the original observer (i.e., if only the section was provided by the observer, then the territory could have been anywhere in the section, or if a quarter section is given, no more accurate than in that quarter section, and so on) and the point representing a territory location could be in a different county than the nest actually was in, 2) where river mile notations are given in the Location field, points represented on the map may not be accurate because the river miles were established years ago with the river often in a different channel, and interpretation of river mile points may vary among observers and among data handlers trying to assign point coordinates to represent a given observation, 3) observers could misidentified which territory breeding birds should be assigned to in subsequent years following the first year in which the territory was described, especially in areas where nesting territories were clumped 4) some observations are combined to represent a number of observations in a single year in one record, and 5) some valid observations with incomplete date are included.
The observation records represent the known historical and recent breeding distribution of Swainson's hawks in California. The majority of records come from in the Central Valley with lesser numbers coming from Siskiyou, Modoc and Lassen counties, and from the Bishop area in Inyo and Mono counties. There are two records from southern California. These data were gathered from 1970 to 1994. Of these, 99.9 percent of the observations were more recent than 1975. Observations were made mainly by doing road surveys through likely habitat to find flying Swainson's hawks during the breeding season. Some surveys were conducted from boats from the Sacramento River. Once Swainson's hawks were seen, they were watched to determine if they were showing courtship or nesting behavior or would lead observers to nest sites or trees that possibly contained nests which could not be easily seen. Once a Swainson's hawk nest was found in an area, other potential nest sites in the general vicinity were checked to see if the hawks were present but not generally visible. Observations were made mainly by Department and other agency biologists and volunteer ornithologists and birders. Observation data was compiled and entered into a database by the Bird and Mammal Conservation Program, Wildlife Management Division, in the late 1980's and additional data were added until mid-1995. WHAT EACH RECORD REPRESENTS The database represents Swainson's hawk observations and known nest sites in California. There are fields describing the number and activity of the hawks observed, if nests and/or young were observed, nest tree species, the observation location (township/range/ section and X-Y coordinates), type of habitat surrounding observation location, and who made the observation and when that observation was made.
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Disclaimer: The State makes no claims, promises, or guarantees about the accuracy, completeness, reliability, or adequacy of these data and expressly disclaims liability for errors and omissions in these data. No warranty of any kind, implied, expressed, or statutory, including but not limited to the warranties of non-infringement of third party rights, title, merchantability, fitness for a particular purpose, and freedom from computer virus, is given with respect to these data.
Use restricted to authorized BIOS users. Recognition that the data set was created and provided by the California Department of Fish and Game.
Extent
| West | -122.548823 | East | -115.028662 |
| North | 41.972651 | South | 34.666020 |
| Maximum (zoomed in) | 1:5,000 |
| Minimum (zoomed out) | 1:150,000,000 |
Disclaimer: The State makes no claims, promises, or guarantees about the accuracy, completeness, reliability, or adequacy of these data and expressly disclaims liability for errors and omissions in these data. No warranty of any kind, implied, expressed, or statutory, including but not limited to the warranties of non-infringement of third party rights, title, merchantability, fitness for a particular purpose, and freedom from computer virus, is given with respect to these data.
Use restricted to authorized BIOS users. Recognition that the data set was created and provided by the California Department of Fish and Game.