There are potentially five subpopulations of Western Yellow-bellied Racers in major river valleys in the arid interior of the province. Western Yellow-bellied Racers in British Columbia are also uncommon, and their numbers have likely declined from historical levels as a consequence of habitat loss associated with the expansion of urban and agricultural areas. Within the past 10 years, the population has declined as a result of a terrain slumping event in Grasslands National Park that killed and displaced snakes from the largest known den of this subspecies in Canada. The Canadian population size is most likely less than 10,000 adults, distributed among four discrete major valleys on the prairies. Based on recent research conducted in Saskatchewan and Alberta, it is evident that Eastern Yellow-bellied Racers are uncommon on the Canadian prairies, and that population dynamics may be negatively affected by habitat fragmentation. Racers are well-camouflaged, fast, wary snakes, which makes it difficult to accurately estimate population sizes or even their presence/absence. They feed mainly on rodents and insects and are beneficial to local ecological processes. Racers are non-venomous and harmless to humans. In Canada, racers are at the northern extent of their global distribution, where they are of high conservation value as such populations often possess unique ecological adaptations. Their sleek body form helps make them extremely fast, while their colouration provides excellent camouflage. Juvenile racers have dark saddle-shaped dorsal markings that fade as the snakes mature. The Eastern and Western Yellow-bellied Racers are olive-green to blue-grey with cream to bright yellow undersides, from which the name “Yellow-bellied Racer” is derived. Racers are long, slender snakes with whip-like tails. foxii addressed in a separate status report). The racer species complex ( Coluber constrictor) has a broad distribution throughout North America, with three subspecies occurring in Canada: Eastern Yellow-bellied Racer ( Coluber constrictor flaviventris), Western Yellow-bellied Racer ( C. Status re-examined and designated Threatened in November 2015. Status re-examined and designated Special Concern in November 2004. Life history characteristics, such as small clutch size and infrequent reproduction by females, increase vulnerability of populations to disturbance, persecution, and changes in land use.ĭesignated Not at Risk in April 1991. Migratory behaviour of snakes between overwintering dens on valley slopes and lowland foraging habitats, together with increasing numbers of roads and traffic volumes, make populations particularly sensitive to road mortality and habitat loss and fragmentation. While relatively little is known of this elusive snake, it likely faces similar threats as other large snakes with which it shares its habitat (Western Rattlesnake, Great Basin Gophersnake). The Canadian distribution of this snake is confined to arid valleys of south-central British Columbia, an area with intensive agricultural development and an expanding human population and tourism industry. Scientific name Coluber constrictor mormon Status Macartney and additions on the Blue Racer by B.D. Committee on the Status of Endangered Wildlife in Canada with additions on the Eastern and Western Yellow-bellied Racers by J.M. COSEWIC status report on the Racer Coluber constrictor in Canada. Committee on the Status of Endangered Wildlife in Canada. COSEWIC assessment and update status report on the Eastern and Western Yellow-bellied Racers, Coluber constrictor flaviventris and Coluber constrictor mormon in Canada. ( Species at Risk Public Registry website).ĬOSEWIC 2004. COSEWIC assessment and status report on the Eastern Yellow-bellied Racer Coluber constrictor flaviventris andWestern Yellow-bellied Racer Coluber constrictor mormon in Canada. This report may be cited as follows:ĬOSEWIC. COSEWIC status reports are working documents used in assigning the status of wildlife species suspected of being at risk.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |