Rattlesnakes at High Elevation
Q: I was surprised on a recent hike in the Tahoe National Forest to see a rattlesnake since we were at about 7,500 feet in elevation. Is that unusual?
A: Based on the picture provided, that’s a western rattlesnake and it’s not unusual to see them at high elevations. There are seven species of rattlesnakes found in California and western rattlesnakes are the most widespread, found throughout the state (except in desert regions) from sea level to 11,000 feet, although they are much rarer above 7,000 feet.
Rattlesnakes use rock mounds, dense vegetation and mammal burrows for thermoregulation, cover from predators and overwintering. Rattlesnakes, like all reptiles, are ectotherms, meaning their metabolic rate and bodily functions are controlled by the temperature in the environment around them. When temperatures consistently drop below approximately 60 degrees Fahrenheit, rattlesnakes go into a hibernation-like state called brumation which can last several months. Rattlesnakes living at higher elevations where it’s colder are typically smaller, due to a shortened time when they can be active and grow.
Fish Trucked to Bays
Q: Is trucking fish still necessary if the drought is over?
A: Drought conditions have played a major role in the decision to use trucks to distribute millions of hatchery-raised salmon to San Pablo and San Francisco bays. During the last multi-year drought, CDFW transported young salmon to more suitable locations due to low river flows and elevated water temperatures, which can be a lethal mixture for the fish.
CDFW salmon hatcheries have traditionally taken a diverse approach in planning strategies used to release fall-run Chinook salmon smolts. Even on the wettest of years the department will incorporate components of releases not just into the rivers next to our hatcheries, but at downstream locations like the San Pablo and San Francisco bays. Releases have also occurred into the ocean, specifically supporting our ocean harvest enhancement programs for anglers. The different tactics help reduce the risk for the overall population, if one of the groups happens to experience losses.
CDFW can track groups of hatchery origin fish as juveniles on their seaward migration and as adults in angler catch reports and when they return to their place of origin to spawn, by retrieving coded wire tags implanted at the hatchery. This data helps inform discussions on the performance of each release strategy and guide decision making on changes to release plans employed each year.
Wildlife Incident Reporting
Q: Why is it helpful to CDFW to have people fill out wildlife incident reports?
A: The Wildlife Incident Reporting (WIR) system is helpful to CDFW as the department continues to learn about the behavior and location of wildlife through reported sightings and encounters. People reporting a wildlife incident are asked for their contact information, the date and location of the incident, the species involved and if they considered it a rare sighting. The information provided to CDFW assists the department in its mission of managing California’s diverse wildlife populations.
When reports are made about conflict with wildlife, the local biologist or human-wildlife-conflict specialist is automatically alerted so they can contact the reporting party to learn more about the incident and offer helpful solutions to preventing additional conflicts. The highest rate of incident reporting happens in late summer and early fall, but it’s not clear to CDFW if that’s when wildlife is most active or when people are more likely to be outdoors experiencing these encounters. The WIR system receives between four and six thousand reports a year with bear, coyote and mountain lion incidents being the most common.
The public is encouraged to report all their wildlife encounters via the WIR. The more people that use the reporting tool, the better and more helpful the data is. The goal of data collection is to assist the department in helping the public respond to wildlife issues. Please see the WIR page.