Coluber constrictor foxii: Difference between revisions
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[[Coluber constrictor foxii]] is a subspecies of [[Coluber_constrictor|Coluber constrictor]] |
[[Coluber constrictor foxii]] is a subspecies of [[Coluber_constrictor|Coluber constrictor]] a non-venomous, [[colubrid]] snakes commonly referred to as the eastern racers. They are primarily found throughout the [[United States]], east of the [[Rocky Mountains]], but they range north into [[Canada]], and south into [[Mexico]], [[Guatemala]] and [[Belize]]. There are currently 11 recognized subspecies. The last reliable record of the blue racer in mainland [[Ontario]] was 1983. On [[Pelee Island]], the species is restricted to the eastern two thirds of the island. In the [[United States]], [[Ohio]], [[Indiana]], [[Illinois]], [[Michigan]], [[Wisconsin]] and [[Iowa]] are now the only states with extant populations of blue racers |
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== Description == |
== Description == |
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The blue racer is one of [[Ontario]]'s largest snakes, reaching lengths of 90 cm to 152 cm snout-to-vent length. The largest documented specimen captured on Pelee Island was 138 cm SVL. Blue racers often have creamy white ventral scales, dull grey to brilliant blue lateral scales, and pale brown to dark grey dorsums. They also have characteristic black masks, relatively large eyes, and often have brownish-orange rostral scales (snouts). Unlike adults, hatchlings and yearlings (first full active season) have dorsal blotches that fade completely by the third year; however, juvenile patterning is still visible on the venter until late in the snake's third season |
The blue racer is one of [[Ontario]]'s largest snakes, reaching lengths of 90 cm to 152 cm snout-to-vent length. The largest documented specimen captured on Pelee Island was 138 cm SVL. Blue racers often have creamy white ventral scales, dull grey to brilliant blue lateral scales, and pale brown to dark grey dorsums. They also have characteristic black masks, relatively large eyes, and often have brownish-orange rostral scales (snouts). Unlike adults, hatchlings and yearlings (first full active season) have dorsal blotches that fade completely by the third year; however, juvenile patterning is still visible on the venter until late in the snake's third season. Although there has been some controversy regarding the designation of C.c. foxii as a subspecies distinct from C.c. flaviventris (the yellow-bellied racers), most recent authorities agree that the subspecies C.c. foxii is valid. |
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== Behavior/Adaptability == |
== Behavior/Adaptability == |
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Blue racers seem to be relatively intolerant of high levels of human activity and foremost of the active season they remain in areas of low human density. |
Blue racers seem to be relatively intolerant of high levels of human activity and foremost of the active season they remain in areas of low human density. |
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Evidence to suggest this comes largely from radio telemetry data from both blue racers and eastern fox snakes that inhabited the same general areas on Pelee Island |
Evidence to suggest this comes largely from radio telemetry data from both blue racers and eastern fox snakes that inhabited the same general areas on Pelee Island |
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(although studies were not conducted concurrently). In contrast to blue racers, fox snakes were often found under front porches, in barns/garages, and in the foundations of houses; whereas, most (but not all) blue racers were observed in more "natural"settings. Therefore, blue racers are more confined to areas with minimal |
(although studies were not conducted concurrently). In contrast to blue racers, fox snakes were often found under front porches, in barns/garages, and in the foundations of houses; whereas, most (but not all) blue racers were observed in more "natural"settings. Therefore, blue racers are more confined to areas with minimal anthropogenic activity. Campbell and Perrin also noted that racers were among the first snakes to disappear from suburban areas. |
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== Habitat == |
== Habitat == |
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Revision as of 07:44, 29 November 2010
| Coluber constrictor foxii | |
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| Blue Racer Snake Coluber constrictor foxii | |
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| Species: | C. constrictor
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| Coluber constrictor Linnaeus, 1758
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Bascanion constrictor | |
Coluber constrictor foxii is a subspecies of Coluber constrictor a non-venomous, colubrid snakes commonly referred to as the eastern racers. They are primarily found throughout the United States, east of the Rocky Mountains, but they range north into Canada, and south into Mexico, Guatemala and Belize. There are currently 11 recognized subspecies. The last reliable record of the blue racer in mainland Ontario was 1983. On Pelee Island, the species is restricted to the eastern two thirds of the island. In the United States, Ohio, Indiana, Illinois, Michigan, Wisconsin and Iowa are now the only states with extant populations of blue racers
Description
The blue racer is one of Ontario's largest snakes, reaching lengths of 90 cm to 152 cm snout-to-vent length. The largest documented specimen captured on Pelee Island was 138 cm SVL. Blue racers often have creamy white ventral scales, dull grey to brilliant blue lateral scales, and pale brown to dark grey dorsums. They also have characteristic black masks, relatively large eyes, and often have brownish-orange rostral scales (snouts). Unlike adults, hatchlings and yearlings (first full active season) have dorsal blotches that fade completely by the third year; however, juvenile patterning is still visible on the venter until late in the snake's third season. Although there has been some controversy regarding the designation of C.c. foxii as a subspecies distinct from C.c. flaviventris (the yellow-bellied racers), most recent authorities agree that the subspecies C.c. foxii is valid.
Behavior/Adaptability
Blue racers seem to be relatively intolerant of high levels of human activity and foremost of the active season they remain in areas of low human density. Evidence to suggest this comes largely from radio telemetry data from both blue racers and eastern fox snakes that inhabited the same general areas on Pelee Island (although studies were not conducted concurrently). In contrast to blue racers, fox snakes were often found under front porches, in barns/garages, and in the foundations of houses; whereas, most (but not all) blue racers were observed in more "natural"settings. Therefore, blue racers are more confined to areas with minimal anthropogenic activity. Campbell and Perrin also noted that racers were among the first snakes to disappear from suburban areas.
Habitat
Pelee Island racers prefer open and semi-open habitat, utilizing the island's alvarsavanna,old field shoreline, and edge habitats. Given the extremely fragmented habitat that currently exists on the island, it is likely that a mosaic of these habitats is required to fulfill the ecological needs of C. c. foxii. Supporting this notion are the extremely large activity ranges documented for this species on Pelee Island.
Compared to other areas of southwestern Ontario, habitat alteration and/or destruction has been relatively slow on Pelee Island and has likely contributed to the blue racer's persistence there. Regardless of the reasons behind this relatively "modest" pace of development in the past, habitat destruction continues at a steady rate, and it is probable that the cumulative impact of this habitat loss is currently having a detrimental effect on the blue racer population. Fortunately, efforts have been underway to increase the quantity and quality of protected habitat on the island, via land acquisitions by groups such as the Nature Conservancy of Canada, and by artificial creation of microhabitats important for the snakes. Several Pelee Island landowners are particularly sympathetic to the blue racer's situation and are allowing enhancement of certain portions of their property for the species.
The blue racer has been on Ontario's Endangered Species List since 1971 consequently, habitat determined to be critical to the snake's persistence is protected (from destruction or significant alteration)under Ontario's Endangered Species Act (ESA). In 1998, blue racer "habitat" on Pelee Island was spatially delineated (primarily utilizing mark-recapture and radio telemetry data collected from 1990-1998), and formally identified for the Conservation Land Tax Incentive Program, Ontario Ministry of Natural Resources (OMNR). Subsequent to the spatial delineation (or mapping) of this habitat, the OMNR determined that these lands should be protected from destruction or human interference as is required under the ESA. The habitat protection afforded by the ESA has significant land use implications, particularly because a substantial percentage of blue racer habitat identified occurs on private lands. Unfortunately, implementing a program to effectively protect endangered species habitat on private lands has been extremely difficult.Several areas known to harbour blue racers and the important microhabitats used by them (e.g., hibernacula) are formally protected on Pelee Island. Lighthouse Point Provincial Nature Reserve and the Stone Road Alvar Complex (owned and managed by the Federation of Ontario Naturalists, Essex Region Conservation Authority, and Nature Conservancy Canada) are the two most important protected areas for the blue racer.
Reproduction
The blue racer is oviparous and average clutch size on Pelee Island for seven females was 14.7 ± 2.53. Females can reproduce annually, but biennial cycles are likely more common. Males can mature physiologically at 11 months but do not have the opportunity to mate until their second full year; similarly, females may mature at 24 months but are not be able to reproduce until the following year. Mating begins in April and continues throughout May. Females oviposit in late June and eggs hatch from mid-August to late-September. The most common nesting microhabitats used by female blue racers on Pelee Island are fallen decaying logs; however, eggs are also laid under large rocks, and in mounds of decaying organic matter. Intra- and interspecific (with eastern fox snake) communal nest sites have been documented on Pelee Island and appear to be relatively common.
References
- Racer - Coluber constrictor Species account from the Iowa Reptile and Amphibian Field Guide
- University of Michigan, Animal Diversity Web: Coluber constrictor
- Species Coluber constrictor at The Reptile Database