Movement and habitat use of headstarted Blanding's turtles in Michigan

Published source details Starking-Szymanski M.D., Yoder-Nowak T., Rybarczyk G. & Dawson H.A. (2018) Movement and habitat use of headstarted Blanding's turtles in Michigan. Journal of Wildlife Management, 82, 1516-1527.
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This study is summarised as evidence for the following.

	Action	Category
	Release captive-bred reptiles into the wild: Tortoises, terrapins, side-necked & softshell turtles Action Link

Release captive-bred reptiles into the wild: Tortoises, terrapins, side-necked & softshell turtles

A randomized study in 2014–2016 in a wetland complex in Michigan, USA (Starking‐Szymanski et al. 2018) found that all released captive-bred Blanding’s turtles Emydoidea blandingii survived their first winter hibernation and most survived at least one year after release. All 24 turtles survived to the spring after release (approximately 9 months) and at least 16 turtles survived for 17 months (only one turtle death was confirmed by the presence of a carcass). Survivorship was lower for turtles released into open water habitat (best case: 5 of 6 turtles survived, worst case: 2 of 6 turtles survived) compared to turtles released into areas vegetated with cattail Typha sp. or willow Salix sp. (best case: 18 of 18 turtles survived, worst case: 13 of 18 turtles survived; no statistical tests were carried out). Average home ranges were larger for turtles released into open water habitat (2.9 hectares) compared to turtles in cattail- or willow-vegetated habitat (0.4–0.6 hectares). In total 24 individuals were selected randomly from turtles bred, hatched and reared in captivity. Turtles were at least one year old and shell length was >10.2 cm. Turtles were released in June 2014 into four wetland habitats (6 individuals per group): open water, sparse cattail vegetation, dense cattail vegetation and willow (see original paper for details). Turtles were monitored by radio transmitter in June 2014–November 2015 (for 515 days in total) once a week during May-September and every two weeks during October–April. Turtles were recaptured autumn 2014, spring 2015, and autumn 2015 to replace/remove transmitters. Best case survival estimates are based on known mortality, worst case include turtles whose radio transmitters were lost or failed and turtles were presumed dead.

(Summarised by: Katie Sainsbury)