11. Chickadee Notes

Wood Turtle in New Brunswick


Wood TurtleThe Wood Turtle, Clemmys insculpta, is widespread in New Brunswick but only locally common. The species is distributed from Nova Scotia to eastern Minnesota south to northern Virginia, but has disappeared or is in decline over much of its range. The Wood Turtle is now considered rare in Ontario, uncommon to rare through New England, and endangered in Wisconsin. There is too little information on the distribution of the Wood Turtle in New Brunswick to state that the species has declined here but the species' increasingly precarious status elsewhere suggests that there is a need to determine its true status in this province. There are no provincial laws that specifically protect the Wood Turtle in New Brunswick but, like all reptiles in the province, the species receives some protection under the Fish and Wildlife Act. Since 1992 international trade in Wood Turtles has been controlled through the Convention on International Trade in Endangered Species, to which Canada is a signatory.

Natural History

The carapace, or upper shell, of the Wood Turtle is brown, grayish-brown, or tan, with radiating straw-coloured lines on the individual plates, or scutes. The grooved, concentric growth rings on each scute form a flattened pyramid giving the shell a sculptured appearance. The plastron, or under shell, is yellow with a single black blotch in the corner of each scute. The head is shiny black, as are the upper parts of the legs and tail. The throat, the lower section of the neck, and the underside of the tail are a bright orange or brick red. The combination of sculptured carapace, yellow and black plastron, and orange throat and forelegs readily distinguish the Wood Turtle from the Painted Turtle and Snapping Turtle, the only other freshwater turtle species native to New Brunswick.

There are no provincial laws that specifically protect the Wood Turtle in New Brunswick...

Carapace length of male Wood Turtles may reach 228 mm, while females are somewhat smaller. Male Wood Turtles are easily recognized by the presence of a concave plastron, a feature that helps the male to balance on the top of the shell of the female during mating. It is clear that Wood Turtles are long-lived, although precisely aging older wild Wood Turtles is difficult. However, during their first 15 years Wood Turtles can be accurately aged by counting the rings, one for each year, in the scutes of the carapace. The average age in several wild populations that have been studied is well over 20 years and there is a record of a captive individual that lived to be 58. Wood Turtles first become sexually active at about 10 years, a good indication of the species' longevity.

The Wood Turtle is a semi-terrestrial species that is active mostly during the day. Although this species may be found far from water, it is most frequently encountered in wooded areas along river and stream floodplains, or in adjacent wet meadows or farmland. Streams or small rivers with hard sand and gravel bottoms and heavily vegetated banks seem to be preferred.

In the early summer Wood Turtles begin to move away from their aquatic surroundings.

Mating may occur during any month in which Wood Turtles are active, but is most frequent in spring and autumn when turtles gather near water. Although preliminary courtship may occur on land, mating usually takes place in shallow water. Most courtship takes place in late afternoon and is initiated by the male.

In the early summer Wood Turtles begin to move away from their aquatic surroundings. Sexually mature females migrate to well established nesting areas, where they will lay their eight to ten white, ellipsoidal eggs. A sand or gravel bank is a frequent nesting site but railroad beds and unimproved woodland roads where there is exposed, light soil may also be used. Nesting usually occurs in the late afternoon and evening, the process extending until dark. In this region nesting occurs in late June and early July. The incubation period varies under the influence of temperature but hatchlings usually emerge from the nest in September or October. Hatchlings are light grayish-brown or tan with a carapace that is about 32 mm long. They lack the bright orange underparts of the adults but will acquire their adult colouration gradually during their first summer.

Raccoons and skunks are the principal predators of Wood Turtle eggs, hatchlings and juveniles, but ravens, coyotes and large predatory fish are also a threat. In some years nearly 100% of eggs produced by a population may be taken by predators. Once a Wood Turtle reaches adulthood its shell may provide protection but raccoons will still sometimes chew off a turtle's tail or front legs. In some populations nearly 10% of the turtles have lost one or more limbs in this way. In areas where increasing urbanization has led to large raccoon populations predation by raccoons on Wood Turtles can become severe.

Wood Turtles consistently occupy the same home ranges from year to year, although the size of these areas of activity may vary among individuals from less than one hectare to more than 100 hectares. For animals that seldom move far from home Wood Turtles demonstrate a remarkable homing ability when displaced. Turtles which have been removed up to 2.4 km from their home ranges have returned within weeks, crossing hills, streams and roadways to do so. Wood Turtles are noted for their dexterity and one was even observed climbing a chain link fence! This species has been reported to have the maze solving ability of a white rat.

Wood Turtles are omnivorous, consuming a variety of plants and animals. They are quick to take advantage of the seasonal availability of foods, taking various berries, willow and alder leaves, insects, earthworms, and molluscs. Wood Turtles are especially fond of strawberries and will also consume dead fish and newborn mice.

Wood Turtles consistently occupy the same home ranges from year to year.

An unusual method of securing food has been reported in Wood Turtles. A turtle will raise itself on one foreleg, drop to the ground, then repeat the process using the other leg. This action produces a rhythmic, drum-like thumping that it has been suggested mimics the pounding of heavy rain. Earthworms, moving to the surface as they would during a downpour to avoid drowning in their tunnels, are readily captured in this way by the turtle. One Wood Turtle was observed to capture eight earthworms in 20 minutes in this way. As the days shorten in September Wood Turtles return to shoreline areas and as temperatures drop they will become less active and spend more time in the water. Wood Turtles hibernate on the bottom of muddy, sandy or lightly gravelled waterways, in this region probably from late September or early October until April or May. On occasion they may overwinter in beaver or muskrat burrows. Wood Turtles frequently congregate during hibernation and groups of as many as 70 turtles have been recorded.

Helping Out

There is very little known about the biology of the Wood Turtle in New Brunswick and there is an obvious need for studies that provide a clear indication of the species' status here. However there is no doubt that human activities are the primary threat to this species.

The Wood Turtle is considered a pollution-intolerant species as it has disappeared from waterways throughout its range where water quality has declined. Pesticides may also be a threat. Insecticides may reduce insect numbers, indirectly affecting Wood Turtles by removing a source of food. We should all strive to reduce or eliminate pesticide use. In some areas significant numbers of Wood Turtles are killed by automobiles as they bask on roads or cross highways. Wherever possible drivers should avoid hitting turtles. Better still, stop and carry the turtle across the road.

...human activities are the primary threat to this species.

The loss of vegetated areas along streams and small rivers, often a feature of increasing urbanization, poor forestry practices or road construction, has reduced populations of this turtle in many areas. Private landowners can help wildlife generally by maintaining wooded borders, or riparian strips as they are called, along waterways. Nesting sites are few on each stream and are easily destroyed by gravel removal, dredging and channelization. Locating Wood Turtle populations in New Brunswick and identifying nesting sites is important if populations of this turtle are to be protected. Anyone finding a Wood Turtle in New Brunswick should leave it undisturbed but should contact the New Brunswick Museum where records on this species are maintained.

In some regions the collecting of Wood Turtles for the pet trade has seriously reduced this naturally tame and non-aggressive turtle. Wood Turtles should not be removed from their natural habitat or transported and released elsewhere.

Further reading

Harding, J.H. and T.J. Bloomer. 1979. The Wood Turtle, Clemmys insculpta...A Natural History. HERP, Bulletin of the New York Herpetological Society 15: 9-26.

Quinn, N.W.S. and D.P. Tate. 1991. Seasonal movements and habitat of Wood Turtles, Clemmys insculpta, in Algonquin Park, Canada. Journal of Herpetology 25: 217-220.

Farrell, R.F. and T.E. Graham. 1991. Ecological notes on the turtle, Clemmys insculpta, in northwestern New Jersey. Journal of Herpetology 25: 1-9.

Ernst, C.H. and R.W. Barbour. 1972. Turtles of the United States. University Press of Kentucky, Lexington, Kentucky.