Newts of Lexington Reservoir Dying By the Thousands

It’s the season of love for the newts of Lexington Reservoir. Each winter, these moisture-dependent amphibians emerge from their summer burrows along the steep slopes of Sierra Azul Open Space Preserve, which is protected and managed by POST’s partner Midpeninsula Regional Open Space District (Midpen). Called by ancient instincts, every cell in their body seems to be pulling them to the calm water of the nearby reservoir: it’s breeding season.

But to get to their breeding sites, these adventurous love seekers must first cross the perilous Alma Bridge Road, a 4.6-mile, two-lane road along the east side of the reservoir that is owned and operated by Santa Clara County. It may not seem like a big deal to us, but when you move just moderately faster than a snail, it’s a life-threatening experience.

One of the largest rates of roadkill reported for any wildlife species in the world is that of the newts at Lexington Reservoir.

It wasn’t until 2017 that Anne Parsons, a trail patrol volunteer with Midpen, noticed something horrific. Walking along this stretch of road she discovered hundreds of newt carcasses crushed by passing cars, a literal massacre of these beloved amphibians. Parson’s intrigue marked the beginning of what would become a community-wide investigation, but no one knew at that time exactly how bad the situation really was.

When It Rains…Newts Migrate Like Wild

Before we go any further, a “birds and the bees” type conversation might be helpful (I know it can be awkward). To start, there are two types of newts found in the greater Los Gatos Creek watershed: the more prevalent California newt (Taricha torosa) and the locally rare rough skinned newt (Taricha granulosa). Both of these species follow similar seasonal migration patterns and utilize the same areas for their breeding grounds.

As amphibians, newts need moisture to keep from dehydrating. So the arrival of the winter rains creates the perfect conditions for these critters to emerge and make a break for it, crawling to the ponds, lakes and creeks where they were born so that they themselves can breed. It’s a homecoming of sorts, and everyone’s on the move.

Over 40% of the population migrating across Alma Bridge Road in the winter of 2020/2021 were crushed by passing cars. If this pattern continues without intervention, it is possible that this local population of newts may disappear in the next 60 years.

Dying for Love:

Galvanized by Pearson’s initial discoveries, a small community of citizen scientists cleverly dubbed the Newt Patrol formed in 2017 to get a better understanding of just how many newts were being lost along this key migration route. The results were startling, with almost 5,000 fatalities documented in the 2018-2019 season. The problem, it seemed, was even bigger than anyone could have imagined.

In light of these observations, folks here at POST, as well as Midpen and a few other agencies, initiated an additional study to build upon this groundbreaking community science data. From November to March of last year (2020/2021), daily surveys were contracted in addition to the ongoing community science efforts. The researchers documented the number of newt carcasses as well as the number of live newts captured via “drift fences,” which corralled the newts toward harmless “pitfall traps” (buried buckets) where they were then carefully counted before being released.

You might want to sit down for the next part. Of the nearly 14,000 adult California newts that are estimated to have attempted to cross the road during the survey period, it is projected that almost 40% were killed by vehicles. The final report (which you can find here) predicts through an approximate modeling of the data that, at this current rate of mortality, this population of newts is on track for possible extirpation (or complete loss) in this location in 60 years.

What If They Were Bunnies?

I don’t mean to be flippant, but a little provocativeness might be a helpful lens for us to peer through for some added insight. It’s hard for me to not wonder what our reaction would be to this ecological massacre if it involved a species that tugged more ubiquitously on our emotional heartstrings (no offense, newts). What would it feel like if the story I just told you was of a different species, something fuzzy and cute, for example, that you might even consider cuddling or keeping as a pet…?

It’s well documented that humans have preferences for certain species and that these preferences play a big role in determining our priorities for conservation. So, without dipping our toe too deeply in this philosophical quagmire, it’s an important consideration for us all to take seriously, one that the survival of this population of newts might ultimately depend upon.

Solutions Exist, Time For Us to Move Too

Though these species aren’t considered threatened or endangered at the state or federal level, the larger conservation community in the Bay Area still has found creative ways to safeguard newts from road mortality. For example, every year the East Bay Regional Parks District initiates a road closure program of South Park Drive in Tilden Park to protect California newts crossing during the winter rainy season. And a group of diehard volunteers in Marin formed a “newt brigade” and claimed responsibility for a key crossing along Chilleno Valley Road.

While some of these options may be viable at Alma Bridge Road in the short term, a group of regional partners that includes Santa Clara County Roads and Airports Department, Santa Clara County Parks Department, Valley Water, community scientists, the Santa Clara Valley Audubon Society and the Sierra Club’s Loma Prieta Chapter, as well as Midpen and POST, are working to identify long-term solutions. Some of these may include: building a safe crossing embedded under the road’s surface, retrofitting the existing tunnels under the road to better accommodate this migration, and/or installing fencing to direct animals (not just newts) to safe areas improved for crossing.

It’s a love story that is still being written but one thing’s for certain, the newts of Lexington Reservoir are on the move and, to stop this heartbreaking carnage, we all need to take action.