Alameda Whipsnake: A Slithery Tail Continues…

A released adult Alameda whipsnake. The blue mark behind the head represents a captured individual and allows staff to monitor recapture rates.

NPS / Angel Sprague

December 2018 - As reported in November 2017, the Natural Resource Management team at John Muir National Historic Site has been working with The Wildlife Project to conduct a survey of the threatened Alameda whipsnake. Their goal is to help determine the occurrence and relative abundance of the snakes within the park.

Funnel traps are situated at the ends of plywood drift fences. Each is equipped with shelter, water, and a food source. The foam board and brick are to keep the trap in place and to protect captured animals from the sun.

NPS / Angel Sprague

Survey efforts during the fall 2017, spring 2018, and fall 2019 trapping seasons show that there is a surprisingly large population of Alameda whipsnakes on Mt. Wanda. The team captured a total of 30 Alameda whipsnakes, including 22 new captures and eight recaptures. Of the 22 total individuals captured, 14 were adults, four were sub-adults and four were juveniles; 17 were male and five were female. Of the eight recaptures, there were seven adults and one sub-adult; six were male and two were female.

A juvenile Alameda whipsnake about to be released. This juvenile was the only individual caught in the fall 2018 trapping season. All of the other whipsnake captures took place during the spring 2018 trapping season.

NPS / Angel Sprague

The majority of individuals were caught at two trap sites. One of the hotspots is in a small chaparral community with rocky outcrops dominated by shrub species, wild oat grass, and oak woodland. The other site is next to a historic orchard dominated by olive trees, chamise shrubland, and blue oak. The survey team had not expected to find so many by the orchard, or in such a small patch of chaparral. A larger patch of chaparral, their preferred habitat, had seemed more promising but yielded only a single capture.

Also unexpected was the capture of three Bewick’s wrens on three separate occasions, and the the complete absence of any rattlesnakes captures. Rattlesnakes are commonly found in the inland East Bay hills, but park staff have yet to document them on Mt. Wanda.

In addition to the collection of surprising and significant data, the survey provided park staff and interns with the training, skills, and experience to qualify for a state and federal permit to handle Alameda whipsnakes. Once acquired, this permit will allow park staff to continue survey efforts and establish a long-term whipsnake monitoring program. These ongoing efforts provide valuable data that will contribute to our overall understanding of the snake’s ecology and population health, and that will inform future park management decisions.

Contact Fernando Villalba to learn more.

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