Posts Tagged: snakes
Rattlesnakes in California Orchards: Growers Beware
First, remember that the desire to avoid any kind of an interaction is mutual. Rattlesnakes are an important part of the ecosystem, feeding on rodents, birds, and other small animals.Snake season in Southern California runs from April through October, but the warmer the weather, the more the reptiles are likely to be out and about. Rattlesnakes are California's only native venomous snake, with some adults reaching up to 6 feet long. According to the California Poison Control Center notes, rattlesnakes account for more than 800 bites each year, with one to two deaths. About 25 percent of the bites are "dry," meaning no venom was injected, but the bites still require medical treatment.There are nine species live in various areas of the state and their size can vary.
According to the University of California Integrated Pest Management Guidelines(2014),the most widespread rattlesnake in California is the western rattlesnake (Crotalus oreganus), found from the northern part of the state as far south as Santa Barbara County and from sea level to 7,000 feet. Two closely related species (C. helleri and C. lutosus) are found in coastal Southern California and in the northern Sierra Nevada, respectively. The sidewinder (C. cerastes) is the smallest rattlesnake and is so named because of its peculiar method of sideways locomotion. The sidewinder is sometimes called the horned rattler because of the hornlike scales above its eyes. It is most commonly found in sandy desert areas from below sea level to 6,000 feet. The Mohave rattlesnake (C. scutulatus) ranges across the desert and foothills of southeastern California from sea level to higher elevations. The southwestern speckled rattlesnake (C. mitchellii) ranges from Baja California northward across much of the Colorado, Mojave, and Sonoran Deserts, overlapping with the red diamond rattlesnake (C. ruber) in western parts of its range and the sidewinder farther east. The Panamint rattlesnake (C. stephensi) is closely related but has a more northerly distribution in the inland desert regions of Southern California. The red diamond rattlesnake is found in Baja California and in southwestern California south of Los Angeles. The western diamond-backed rattlesnake (C. atrox) is seldom seen in California but occurs in the extreme southeastern part of the state in desert regions.
Of the nine species of rattlesnakes in this region, the Western Diamondback rattlesnake is probably the most dangerous because of its size and aggressive nature. State experts say the Diamondback can be found primarily in Imperial, Riverside and San Bernardino counties. Most trees crops that are found in this county that are at risk for hosting these snakes are avocados, citrus and dates.
This vertebrate pest can cause a threat to workers conducting routine agriculture cultural practices such as irrigating, fertilizing, and harvesting. In the deserts of Riverside and Imperial county where the laborious date palms are grown, rattle snakes can cause a threat to harvesters if orchard vegetation is left uncontrolled. The snakes are also attracted to water, so irrigators can run the risk of coming into contact with the snakes.
Biology and Behavior
Rattlesnakes are thick-bodied snakes with keeled (ridged) scales in a variety of colors and patterns. The National Wildlife Federation reported that rattlesnakes typically live for 10 to 25 years.
Most species are patterned with dark diamonds, rhombuses or hexagons on a lighter background. Rattlesnakes are ovoviviparous, which means that eggs incubate inside the mother's body. Babies are born live, encased in a thin membrane that they puncture after being born.
They are among the group of snakes called pit vipers because of the small pits on each side of the head between the eye and nostril. These pits are temperature-sensitive structures that assist the snake in finding prey, even in complete darkness. The tongue is also used to detect the scent of prey. Rattlesnakes have a specialized venom delivery system. Venom is produced in glands behind the eyes and then flows through ducts to the hollow fangs. Normally the fangs fold back against the roof of the mouth and when a snake strikes, the fangs pivot forward to inject venom.(Kardong and Bels, 1998).
The California Department of Fish and Wildlife recommends being alert and also having a sense of where a rattlesnake could be at a particular time of day. After a cold night, the snakes will try to raise their body temperatures by laying out in the sun around mid-morning. To prevent overheating during the day, they may be more active at dusk, dawn and nighttime hours.Though they are not nocturnal, in the hot summer months they may be more active at night.
Management
The nine species of rattlesnakes found in California are not considered endangered or threatened. California Department of Fish and Wildlife Code classifies rattlesnakes as native reptiles. California residents can take most rattlesnake species on private lands in any legal manner without a license or permit, although a bag limit of two still applies. Additionally, the red diamond rattlesnake (C. ruber) is prohibited from being taken or killed by state wildlife regulation.
Habitat Modification
Most rattlesnakes seek cover in crevices of rocks, under surface objects, beneath dense vegetation and in rodent burrows, so eliminating potential shelter is critical. Adults eat live prey, primarily rodents; the young consume mostly lizards and young rodent.Controlling the vermin population in your orchard ia an important factor as the rodent borrows can become a snake's new homes. Weed management in orchards are critical during the warmer months. The vegetation can be a habitat for snakes.In addition,pruning or removing old trees from the orchard, proper disposal of the wood is important. Stacking or saving the wood in piles create a habitat for the rattlesnakes.
Exclusion
Structures for farming operations can vary in size and age. Chemical sheds, equipment garages, machinery shops are infamous to hosting snakes. In summer, rattlesnakes may be attracted to cool and/or damp places, such as beneath buildings. Sealing all cracks and other openings greater than 1/4inch can prevent them from entering. Gaps beneath doors are often large enough to permit snakes to enter, especially young ones.
Benefits
According to the University of California Integrated Pest Management Guidelines(2014),rattlesnakes add to the diversity of our wildlife and are important members of our ecosystem. They can reduce the number of disease carrying rodents and other pest species. In general, they should be left alone, whenever possible, especially in wildland areas. Nonvenomous snakes, such as gardener snakes should also be left alone wherever found.
References
California Department of fish and Wildlife. https://www.wildlife.ca.gov/Keep-Me-Wild/Rattlesnakes. Accessed 20 June 2019.
California Poison Control. https://calpoison.org/topics/rattlesnakes. Accessed 20 June 2019.
Kardong, K. V. and Bels, V. L. 1998. Rattlesnake strike behavior: kinematics. Journal of Experimental Biology, 201(6), 837-850.
National Wildlife Federation. https://www.nwf.org/Educational-Resources/Wildlife-Guide/Reptiles/Rattlesnakes. Accessed 20 June 2019.
Salmon, T. P., D. A. Whisson, and R. E. Marsh. 2006. Wildlife Pest Control Around Gardens and Homes. 2nd ed. Oakland: Univ. Calif. Agric. Nat. Res. Publ. 21385.
Todd, B., T.P. Salmon, D.A. Whisson and R.E. Marsh.University of California Integrated Pest Management Guidelines http://ipm.ucanr.edu/PMG/PESTNOTES/pn74119.html. Accessed 20 June 2019.
Walter, F. G., U. Stolz, F. Shirazi, J. McNally. 2009. Epidemiology of severe and fatal rattlesnake bites. Philadelphia: American Association of Poison Control Centers' Annual Reports. Clin. Toxicol. 47:663-669.
Love ’em or hate ’em, snakes are good for your garden
Some 45 of my Master Gardener friends and I recently went on a field trip to Berkeley's UC...
Gopher snake: friend or foe?
Gopher Snakes (Pituophis catenifer), known as a constrictor snake, are one of the most commonly seen snakes in California. Mainly active during the day, they are active after sundown on hot days. They are often observed crawling across trails and roads, especially in the morning and evenings when daytime temperatures are high. They live in diverse habitats and are regularly seen around human residences, including suburban backyards and in agriculture commodities as they are attracted to the rodents which thrive in those areas. The gopher snakes help growers control their pest problems by preying on rodents, rabbits, and birds that would otherwise destroy or ruin crops and yields. When the weather turns hot, they hunt during the night and rest on warm rocks or pavement during the day. They hibernate during the winter and are out and about between April and October, however in Southern California because of the warm climate their presences is more consistent.
Gopher Snakes are large and heavy-bodied reptiles - reported to reach 9 feet (275 cm) in length, but 4 feet (120 cm) is more common. The underside is creamy or yellow, often with dark spots. Unfortunately, this harmless and beneficial species is very often killed out of fear that it is dangerous or that it is a rattlesnake. Since the patterns on their backs are similar to rattlesnakes and because they coil, vibrate their tails, and even strike when threatened. Other differences include: gopher snake tails taper to a thin tip and lack rattles; rattlesnake tails always have rattles (or immature buttons), unless the rattle has broken off, gopher snake heads are usually narrow, while rattlesnake heads are always triangular, and gopher snake eyes have round pupils, while rattlesnake pupils are vertical.
So, if you see a Gopher snake in your grove, its best to leave him alone so that it can contribute to your Integrated Pest Management plan.
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Snakes in a Tree!
Who knew gopher snakes climb trees? We learned that they could when my husband saw one climb (slither?) up our backyard orange tree.
On a recent afternoon, my husband and daughter discovered a large snake winding its way along a backyard path of our suburban home. The snake apparently tired of having its picture taken and slowly made its escape up our orange tree. Based on the snake’s markings, my husband concluded that it was a California Night Snake, which is described as mildly venomous, but not dangerous to humans. You can imagine my surprise when I was told that we had a venomous tree snake in our backyard! On further research and consultation with the California Academy of Sciences’ Herpetology Department, however, we learned that our snake was merely a “garden-variety” gopher snake.
I am used to see gopher snakes out in the field, but not in a truly suburban environment. Since then, however, I have learned that gopher snakes one of the more common snakes in California. They are often seen around human dwellings, including suburban backyards, because they are attracted to rodents in the area.
Wait. Attracted to rodents? What rodents?! Alas, within two days, we found out when we spotted a rat raiding our bird feeder. Ugh. Now we have given up filling our bird feeders (which I miss quite a bit) and are trying to be better about picking up fallen fruit, and we are rooting for our tree-climbing gopher snake to do its job. Even though we haven’t seen the snake since that one day, we can’t persuade our children to pick oranges anymore!
References:
http://www.saczoo.org/document.doc?id=356
http://www.californiaherps.com/identification/snakesid/gophersnakes.id.html
Gopher snake (photos by Erin Mahaney)
Snake making its way onto the tree.
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