Red-eared Slider (Trachemys scripta elegans) nests in the Greater Toronto Area

Red-eared Slider (Trachemys scripta elegans) is a non-native turtle found in abundance in Toronto’s wetlands as a result of pet releases. Although this species is known to reproduce successfully in southwestern Ontario, Canada, there is yet no evidence to suggest successful reproduction in the Greater Toronto Area (GTA). As part of a native turtle nest protection program, volunteers inadvertently placed nest protector boxes over four slider nests in 2021 and 10 nests in 2022. This gave us the opportunity to determine whether nests produced viable offspring and whether these hatchlings would emerge in the fall. The exact nesting date for each nest was recorded. In 2021, eight of the 41 eggs from the slider nests showed very late-stage arrested embryonic development. In 2022, one of the nests had four hatchlings out of their eggshells but still inside the nest cavity. It is unclear whether the hatchlings would emerge later in the fall or overwinter in the nest cavity and emerge the following spring. If the small population sampled accurately reflects what occurs in the GTA, complete egg development may be possible for this species in some years, in some locations, with the right local micro-climate and micro-habitat. We discuss implications for turtle nest protection in Toronto.