File Geodatabase Feature Class
Tags
giant garter snake, Thamnophis gigas, reptile, population, distribution, monitoring, Central Valley, rice fields, wetlands, California, biota, environment
These data were collected for a variety of projects with specific objectives over the last 10 years. Generally the purpose was to examine the distribution and abundance of the giant garter snake (Thamnophis gigas), and monitor populations.
The USGS surveyed for giant garter snakes (Thamnophis gigas) in the Central Valley of California by trapping from 1995 to 2004, to determine distribution and abundance of snakes. A total of 1484 individual giant garter snakes were captured, and 1305 recaptures were recorded. An additional 324 snakes were observed but not captured. Capture Techniques: We deployed modified floating funnel traps (Casazza et al. 2000) from April through September, to trap giant garter snakes in selected habitats. Traps were checked daily during the study period. The location of traps, snake captures and sightings were recorded using GPS. All information was entered into an Access database. Measuring and Identifying: Each snake was processed as soon as possible after capture to determine sex and its weight, snout to vent length and total length were measured. Snakes were positively identified using taxonomic determinations such as labial scale counts and dorsal scale counts at mid-body, as well as stripe and background color (Rossman et al. 1996). Snakes were permanently marked using passively induced transponder (PIT) tags. Individuals were scanned to detect PIT tags and previously unmarked snakes were injected with PIT tags. After measuring and marking, snakes were released at the point of capture. References: Casazza, M. L., G. D. Wylie, and C. J. Gregory. 2000. A funnel trap modification for surface collection of aquatic amphibians and reptiles. Herpetological Review 31(2), 91-92. Rossman, D. A., N. B. Ford, and R. A. Seigel. 1996. The garter snakes: evolution and ecology. University of Oklahoma Press, Norman, OK. 332 pp.
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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 of this dataset requires approval of the primary contact.
Extent
| West | -122.166140 | East | -120.709191 |
| North | 39.503948 | South | 36.975694 |
| 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 of this dataset requires approval of the primary contact.