Rodenticides Threating California’s Carnivores – a Firsthand Account

I haven’t seen a Bobcat in my neighborhood in over four years, and not for lack of effort. I often take walks, and every time I travel along the roads near our house, I keep an eye out for anything animal shaped: in fact, in the past few months, I’ve seen six coyotes, lots of deer, several Jackrabbits, Brush Rabbits, Wild Turkey, and even a Dusky-footed Woodrat. But why no Bobcats – an animal that I used to observe as often as many of these other species? I’ve  wondered about this matter for a long time, and while hiking a few years ago at Rancho San Antonio, my local county park, I often observed signs indicating sick Bobcats and urging visitors to report sightings of any Bobcats they observe. However, at that time, I felt that it must have simply been a transient disease epidemic that was due to end sometime soon…

A few weeks ago however, we received a notice that stated otherwise: dozens of Bobcats were reported sick or dead in my local area and many rangers even described watching fur-less, emaciated bobcats die in meadows where I’ve seen healthy Bobcats before. I soon realized that many of the first Bobcats I observed years ago were now deceased, and population of these wonderful wildcats I once enjoyed was now seriously depleted, if not gone for the foreseeable future. The reason? Anticoagulant rodenticides. Local use of these toxins by contractors and landscapers causes rodents to not die immediately, but move about hindered and stunned. Predators such as Bobcats, seeking easy prey, eat these poisoned rodents, and then become ill themselves, soon dying a painful death. The Midpeninsula Regional Open Space District has now taken a powerful stance against these terrible poisons, and many are advocating for the toxins to be banned altogether throughout California.

This problem of Anticoagulant Rodenticides, particularly Second Generation Anticoagulant Rodenticides (abbr. SGARS), is not limited to the SF Bay area. Bobcats have been reported sick and dead in the suburbs of Orange County, as well as in San Diego County too. Moreover, these toxins don’t only affect Bobcats. Biologists are concerned of the welfare of populations of the Federally Endangered San Joaquin Kit Fox in the Bakersfield area too, as well as in small carnivores in the Southern Sierra Nevada. On my recent trip to Northwestern California’s Klamath Mountains in Humboldt County (trip report coming soon), I learned of several new species the SGARS were affecting too in that region. While SGARS are primarily used by landscapers and contractors in the metropolitan areas of the Bay Area and Southern California, a very different and more sinister cast of characters use these in the Northwest: illegal pot growers. Speaking to local naturalist and bird expert Rob Fowler, I realized these toxins, used to protect marijuana plants in Humboldt, Trinity, and Mendocino Counties, were having similar effects on local predator populations in that region too.

The Pacific Fisher, a large cat-sized member of the weasel family, once occurred commonly in moist forest habitats of Idaho, Montana, Oregon, Washington, and Northern California. Due to immense pressure from the fur trapping industry, this species is now only present in localized pockets of the Northwestern Montana, Extreme Northeast Idaho, the Olympic Peninsula, Sierra Nevada, and Klamath Mountains. And the Klamath Mountains of Northwestern California and Southwestern Oregon, with a Pacific Fisher population numbering in the low thousands, are thought to hold the largest and most significant population of these rare forest carnivores. However, even in their present stronghold, this elusive animal is under threat. The Hoopa Valley Indian Reservation, a rugged region of moist Douglas-fir and Tanoak Forests previously contained the healthiest and most important Fisher population in California. However, recent surveys have indicated that since the late 1990s, there has been a >70% drop in Fisher numbers on the Hoopa lands. Biologists, puzzled at this sudden population decline, researched potential causes: disease, increased predation, and more, but still couldn’t connect the pieces of the puzzle. However, several sad discoveries in remote regions of the reservation finally connected the clues: dead and dying fishers, with little to no external trauma were found and examined. Once dissected, biologists noticed large amounts of bleeding in the animals’ bodies, discovering that SGARS used at illegal marijuana farms were at fault. Alarmed, they began testing other dead fishers found previously for SGAR presence: they found the toxins present in the bloodstream of over 80% of deceased fishers. Further testing on other predators in the region, such as Bobcats, Mountain Lions, Minks, Foxes, Bears, and rare Spotted Owls confirmed the biologists’ worst fears: the toxins had cascaded through the ecosystem in Hoopa, just as they had in many other areas of California. As biologists researched the matter further, the evidence against SGARS mounted: cans of poison were found throughout the landscape, some even near creeks; one grow site even had poisoned hot dogs hanging from fisher hooks – not doubt used to poison the unlucky bear or other carnivore curious enough to taste. Amounts of poison enough to kill over 20 bears, hundreds of woodrats, and dozens of Fishers and Spotted Owls! This behavior is just disgusting and should not be condoned on any level.

However, there is hope. Starting May 20, 2014, California banned the use of household anticoagulant rodenticides, particularly the most potent SGARS – a good step in the right direction. However, these products are still available to licensed operators. Too many loopholes still exist for criminals such as pot growers to gain access to these poisons and the only solution to this problem is to block access completely. The problem isn’t just a wildlife issue, it’s estimated that over 10000 children are exposed to Anticoagulant Rodenticides every year. Let’s support a cleaner, healthier environment and remove these poisons from California.

Thanks for reading,

Venkat

Please read more about the problem:

Here for Bobcats in the Bay Area: http://saferodentcontrol.org/site/wp-content/uploads/2013/11/Midpeninsula-Regional-Open-Space-Dist.pdf

And here for Fishers in NW California: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0040163

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Field Trip — Giant Kangaroo Rats, etc. in Panoche Valley (April 2014)

The Panoche region of Southern San Benito County is a place I’ve talked about quite a bit here, so I think it would be a good idea to give a bit of a description of the area’s natural history and also provide a trip report covering some of my favorite locations in the region for wildlife viewing and nature study. I hope that reports like this can provide incentive for anyone wishing for a little adventure and nature to visit this amazing place and raise awareness of the peril habitats such as this one are currently in.

Panoche Valley is an arid valley located in the Southeastern part of the Diablo Range Mountains of Central California. If you’ve ever driven down the I-5 between Sacramento and LA, whether you know it or not, you’re probably familiar with the Diablo Range – that endless stretch of hills that accompany you on the straight road for about five hours! The Diablo Range is part of California’s interior Coast Ranges, and Panoche Road between Hollister and the Valley is actually the perfect place to experience this mountain chain. The Diablo Range is dry, bleached and barren on exposed southern and eastern slopes, with scattered chaparral and oak woodland and even occasional pines on cooler North slopes. The primary vegetation types in these mountains are oak woodland and chaparral. Oak woodland occurs on moister sites, primarily composed of Blue Oak, with occasional Valley Oak along streams and Black Oak in more mesic areas. Gray (also known as Digger, Foothill, and Ghost) Pines are also conspicuous, decorating the landscape with their long wispy blue needles and scrappy, black forked trunks. In chaparral, the vegetation in the area is primarily Chamise, California Sagebrush and Coyote Brush, with occasional California Juniper and Yucca. This type of environment supports classic California mammal and bird life: Black Tailed Deer are abundant, as are Desert Cottontails, Wild Turkey, and Wild Pigs. Careful and lucky observers may spot a Bobcat, Gray Fox, Coyote, or even a Mountain Lion. At night, there are good chances of observing Striped Skunks and Raccoons; the rodent community in these hills is also diverse, featuring Dusky-footed Woodrat, Deer Mouse, and California Pocket Mouse in the oak woodland, with Desert Woodrat and Coast Kangaroo Rat in chaparral. Typical California oak woodland birds such as Rufous-crowned Sparrow, Rock and Canyon Wrens, Yellow-billed Magpie, Lewis’s Woodpecker, Golden Eagle, Prairie Falcon, and Phainopepla are common.

However, once one nears the valley, the vegetation communities, as well as the resulting wildlife, change drastically. Panoche Valley and the neighboring Vallecitos Valley provide a good example of what many areas of the San Joaquin Valley were like prior to the advent of farming and irrigation. It is a dry, sandy plain covered in shortgrass prairie – one of the last vestiges of habitat for many rare mammal and bird species that depend on the California grasslands. Local areas of native shortgrass habitat provide refuge for rare plant species such as Panoche Creek Larkspur and San Joaquin Woollythread. This is the land of the San Joaquin Kit Fox, American Badger, San Joaquin Antelope Squirrel, and of course, the Giant Kangaroo Rat. The rodent community is particularly diverse, with an additional two kangaroo rat species present, alongside two species of pocket mice and the unusual Tulare Grasshopper Mouse. The area is also noted as globally important for its wintering birdlife. Panoche Valley is one of California’s most important locations for wintering Mountain Plovers, and also sustains a host of other grassland specialties including Say’s Phoebe, Loggerhead Shrike, Cassin’s Kingbird, Ferruginous Hawk, Prairie Falcon, Long-billed Curlew, Short-eared Owl, Vesper Sparrow, and more! At its winter birding prime, the valley’s beautiful grasslands come alive with huge flocks of Savanna, Lark, and White-crowned Sparrows, Tricolored Blackbirds, Horned Larks, and Mountain Bluebirds. The area also contains three seasonal Creeks: Panoche (Silver) Creek in the East, the Arroyo Los Pinos in the Vallecitos to the South, and Little Panoche Creek in the North, which provide habitat for threatened amphibian species and pond turtles. The rare Blunt-nosed Leopard Lizard’s preferred denning sites are along the walls of dry creeks, such as the Arroyo Las Aguilas in the West of the Panoche Valley.

The final element of the Panoche region are the Desert Hills. This is the domain of many special reptiles, such as the San Joaquin Coachwhip, Blunt-nosed Leopard Lizard, Long-nosed Snake, California Glossy Snake, and California Legless Lizard. Two lizard species common in California’s southern desert, the Night Lizard and Yellow-backed Spiny Lizard are present at their northern range limits here too. The tiny Sage Sparrow, a species common in the Mojave and Great Basin Desert occurs in these hills, one of the most pristine remnants of the once vast San Joaquin Desert – California’s fourth major desert (Great Basin, Mojave, and Colorado being the other three), as does the Greater Roadrunner. The hills also contain unique plant communities, such as Ephedras, Junipers, Sagebrush, and Yuccas, ecosystems not easy to find near the Bay Area. To the south of the Ciervo Hills and Vallecitos, the Panoche region even contains true mountains. San Benito Mountain, the highpoint of the Diablo Range, towering to over 5000 feet, provides montane pine forests, mountain bird communities, unique serpentine ecosystems, and even snow in winter.

Now for my trip (there’s so many amazing things in the region that it’s easy to almost forget the topic at hand!)… We drove through the Diablo Range towards the valley in the late afternoon, observing Rufous-crowned Sparrows, and a Coyote. Near the Valley, a surprise awaited with a massive Golden Eagle taking off from a dead wild piglet near the road, showing off its impressive 6-foot wingspan! Back in the valley, we soon found California Ground Squirrels and Cassin’s Kingbirds, and then headed for the hills. There, I found Bell’s Sparrows, Lark Sparrows, and Horned Larks easily, but my main target were kangaroo rats, which were seen in significant numbers in the area the previous week. However, conditions change and as soon as night fell, despite searching the roads, I never found any wildlife. Continuing down past Mercey Hot Springs, I finally observed my first two Kangaroo Rats of the night: 1 tiny, grayish San Joaquin Kangaroo Rat followed by a small, brown Heermann’s Kangaroo Rat in the western valley. After crossing Panoche Creek on the road, I scanned the plains beyond in Silver Creek Ranch, finally observing over 20 Giant Kangaroo Rats as well as a small number of Heermann’s Kangaroo Rats. Returning back, I found amazing views of a Giant Kangaroo Rat by the roadside. However, the night wasn’t over yet: returning back through the Diablo Range, my last wildlife sighting was of a large Badger that quickly disappeared into the roadside brush!

Panoche Valley is an amazing place that deserves all the public awareness it can get. I encourage everyone willing to to make a trip to this amazing region and perhaps, with luck, enjoy some of its very special animal and plant life!

See you there!

Venkat