Headstarting as a management tool: A case study of the plains gartersnake

Published source details King R.B. & Stanford K.M. (2006) Headstarting as a management tool: A case study of the plains gartersnake. Herpetologica, 62, 282-292.
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This study is summarised as evidence for the following.

	Action	Category
	Maintain wild-caught, gravid females in captivity during gestation Action Link
	Release reptiles born/hatched in captivity from wild-collected eggs/wild-caught females without rearing Action Link
	Head-start wild-caught reptiles for release: Snakes & lizards Action Link
	Use hormones and/or other drugs during captive-breeding programmes to induce reproduction/birth Action Link

Maintain wild-caught, gravid females in captivity during gestation

A replicated study in 1995–2001 in a captive setting in Illinois, USA (King & Stanford 2006) found that gravid plains gartersnakes Thamnophis radix maintained in captivity produced some live offspring. From 38 litters, 473 offspring were alive (79%) and 128 were stillborn (21%). From 18 litters obtained by inducing females with oxytocin, 343 offspring were alive (67%) and 112 stillborn (33%). In 1995–2001, gravid females were captured (number not given) and maintained in captivity in individual glass aquaria (40 l) until giving birth. The room was kept at 24–26°C (32°C at one end of aquarium) and humidity at 50%.

(Summarised by: Maggie Watson, William Morgan)
Release reptiles born/hatched in captivity from wild-collected eggs/wild-caught females without rearing

A replicated, controlled study in 1995–2001 on an urban river bank with a mix of mown lawns and riparian vegetation in Illinois, USA (King & Stanford 2006) found that captive-born plains gartersnakes Thamnophis radix from wild-caught, gravid females that were released as newborns had low survival in the wild, which was similar to wild-caught newborns. Twenty-seven of 362 (7%) captive-born snakes released as newborns and 2 of 15 (13%) wild-caught newborns were recaptured one or more years after release or initial capture. Seven snakes released as s reached maturity during the study, and two of these were gravid (aged 21–22 months old). In 1995–2001, gravid females were captured (number not given) and maintained in captivity until giving birth. Snakes born in 1998 (137 snakes), 2000 (188 snakes) and 2001 (71 snakes) were released within 2–27 days of birth. Recapture effort varied between months and years, but most snakes were recaptured by hand in April–June 1998–2001.

(Summarised by: Maggie Watson, William Morgan)
Head-start wild-caught reptiles for release: Snakes & lizards

A replicated, controlled study in 1995–2001 on an urban river bank with a mix of mown lawns and riparian vegetation in Illinois, USA (King & Stanford 2006) found high survival during head-starting of plains gartersnakes Thamnophis radix, and that post-release survival was comparable to wild-caught snakes. Overall survival during head-starting was 76% (217 of 286 snakes). The number of snakes recaptured one or more years after release was similar for head-started (5% of 142 snakes and 26% of 53 snakes) and wild-caught snakes (20% of 80) (result not statistically tested). Growth rate was similar for head-started and wild-caught snakes (data reported as statistical model result). Three head-started females were gravid when recaptured (23–24 months old). In 1995–2001, gravid females were captured (number not given) and maintained in captivity until giving birth. Snakes born in 1995 and 1996 (53 snakes) were head-started for 327–335 days, while those born in 1999 (142 snakes) were head-started for 253–260 days. Recapture effort varied between months and years, but most snakes were recaptured by hand in April–June 1998–2001.

(Summarised by: Katie Sainsbury)
Use hormones and/or other drugs during captive-breeding programmes to induce reproduction/birth

A replicated, controlled study in 1995–2001 in a captive setting in Illinois, USA (King & Stanford 2006) found that inducing gravid plains gartersnakes Thamnophis radix with oxytocin resulted in similar birth success compared to females not induced. Results were not statistically tested. From 18 broods obtained by inducing females with oxytocin, 343 offspring were alive (67%) and 112 stillborn (33%), and from 38 litters obtained with no oxytocin, 473 offspring were alive (79%) and 128 were stillborn (21%). In 1995–2001, gravid females were captured (number not given) and maintained in captivity in individual glass aquaria (40 l) until giving birth. The room was kept at 24–26°C (32°C at one end of aquarium) and humidity at 50%.

(Summarised by: Maggie Watson, William Morgan)