Northern Pacific Rattlesnakes (C. viridis oreganos) – also refered to as “Western Rattlesnakes” occur in the Okanagan, most common on dry hillsides but rarely occurring higher than 1000m above sea level. The Okanagan Similkameen Stewardship (OSS) states they are variable in colouration and pattern, but all belong to the same species. There are no other species in the province. They den in hibernacula, usually with other species of snakes.
Distribution – Eight subspecies of the Northern Pacific Rattlesnake are recognized, but only one species, the C. viridis oreganus occurs in British Columbia at the northern end of its range, extending from California. British Columbia’s population is small and confined to dry grasslands in Bunchgrass, Ponderosa Pine zones of Okanagan-Similkameen, Thompson, Nicola and Kettle valleys, as well as the Lytton-Lillooet portion of the Fraser Canyon.
Habitat – Found in rocky terrain or talus areas in forest or grassland habitats. Migration takes place in spring to favourite foraging and basking areas up to 1 km from den. In summer, rattlesnakes are found in open grassland and areas with high rodent densities. They bask on sunny, rocky ledges with scattered shrubs for shade. The Bunchgrass zone is a grassland area characterized by dry conditions and dominated by species like bluebunch wheatgrass and big sage. The Ponderosa Pine zone, on the other hand, features forests of ponderosa pine and is located in low elevations of dry valleys.
The ponderosa pine zone (PP zone) takes its name from the ponderosa pine forests that typify the area. The majestic ponderosa pine occupies low elevations in the dry valleys of the southern Interior Plateau and East Kootenays and consists of a visually satisfying mosaic of forests, grasslands and wetlands. This zone is home to a wide variety of birds, mammals, reptiles and amphibians.
Snakes hibernate from September to April, returning to the same communal den each year. Hibernating dens are in rock fissures or caves; located on south facing rocky slopes or ridges at elevations of 500 to 625m.
Food Habits – Adults eat mainly voles and mice, ground-nesting birds, pocket gophers, wood rats, squirrels, chipmunks, muskrats, ground squirrels, young marmots, and young rabbits; young eat mainly newborn voles and shrews. Foraging occurs from dusk to dawn. A snake’s body coils and strikes forward when attacking prey; one-half of body length is the normal striking distance. Prey are stabbed and injected with venom from hollow fangs; venom glands are located behind and below each eye on upper jaw. Venom is chemically complex, but primarily acts to break down proteins (e.g. blood vessel walls); also affects nervous system. (Source: Ministry of Environment)
Why Do Snakes Visit Residential Yards?
Snakes don’t typically seek out humans, but they are naturally drawn to environments that offer food, shelter, and safety. Food Sources – Snakes primarily feed on rodents, frogs, insects, and sometimes small birds. A yard with abundant wildlife or pest activity will naturally attract snakes hunting for meals. Shelter – Snakes look for cool, shaded, and secure hiding spots to escape heat or predators. Dense vegetation, woodpiles, and garden debris provide ideal cover. Water – Snakes need water to survive. Ponds, birdbaths, or even standing water in planters can increase the chances of snakes visiting.
Landscape Features That May Attract Snakes
Certain common yard and garden elements can unintentionally invite snakes. Thick Ground Cover and Overgrown Shrubs – Dense shrubs, ivy, and ground covers offer perfect hiding spots for snakes to feel secure and ambush prey. If overgrown or close to the home foundation, these areas become hotspots for snake activity. Woodpiles and Rock Piles – Stacked wood and rocks create dark, cool crevices where snakes can rest during the day.
They also attract rodents, which increases food availability for snakes. Mulch and Leaf Litter – While mulch and leaves are great for garden health, they also retain moisture and provide shelter for insects and small animals, which can in turn attract snakes. – Garden ponds, fountains, and birdbaths offer water sources that snakes seek. These features may also attract frogs and insects, adding to the food supply. Tall Grass and Weeds – Unkempt lawns or areas with tall grass and weeds provide cover for snakes to move unseen. Snakes prefer to avoid open, sunny spaces, so shaded grassy areas are particularly attractive.
Manage Snake Attractants
Fill holes around your house and outbuildings – if mice can get in, a snake can too. Remove piles of wood, rocks or other materials that may provide convenient retreat sites for snakes. Close in decks and stairs so that snakes cannot enter storage areas where they feel safe. Keep a rodent-free yard. Compost pile, pet food, garbage and spillage from bird feeders attract rodents which are primary prey of rattlesnakes. Water features can attract snakes. Keep bird baths well off the ground. Consider installing snake barrier fencing around your home and yard. (Source: Wild Safe BC)
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