The Jamaican iguana (Cyclura collei): a report on 25 years of conservation effort

Published source details Wilson B., Grant T.D., Van Veen R., Hudson R., Fleuchaus D., Robinson O. & Stephenson K. (2016) The Jamaican iguana (Cyclura collei): a report on 25 years of conservation effort. Herpetological Conservation and Biology, 11, 237-254.
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This study is summarised as evidence for the following.

	Action	Category
	Head-start wild-caught reptiles for release: Snakes & lizards Action Link
	Create artificial nests or nesting sites Action Link
	Breed reptiles in captivity: Lizards Action Link

Head-start wild-caught reptiles for release: Snakes & lizards

A before-and-after study in 1991–2015 in old-growth tropical dry forest in Jamaica (Wilson et al. 2016) found that after releasing head-started Jamaican iguanas Cyclura collei (along with associated actions), the number of nesting female and hatchling iguanas increased over 23 years. Results were not statistically tested. After 23 years of head-starting and releasing Jamaican iguanas, 321 iguana hatchlings and 63 nesting female iguanas were counted compared to 31 hatchlings and 9 nesting females at the start of the programme. The first new wild-born female iguana joined the breeding population after 16 years. The authors reported that health of head-started individuals was generally good but that 16% died or were lost prior to being released. In 1991–2015, Jamaican iguana eggs and hatchlings were collected from the wild and head-started in a zoo. Head-started individuals were released in 1996 (278 total iguanas released, usually 6–8 years old or 1–2 kg). In 1997–2014, non-native mammalian predators (mongoose Herpestes javanicus, cats Felis catus, dogs Canis lupus familiaris and feral pigs Sus scrofa) were removed using baited cage traps, snares and leg-hold traps (around 1,500 predators in 350,000 trap days over 17 years using 20–300 cage traps). In 2011–2012, an artificial nesting site was constructed 40 m south of the main nesting area. During the nesting season in 1991–2015, nests were checked daily and adult female iguanas were monitored by live trapping, observation and camera traps.

(Summarised by: Katie Sainsbury)
Create artificial nests or nesting sites

A before-and-after study in 1991–2015 in old-growth dry limestone forest in Jamaica (Wilson et al. 2016) found that when an artificial nesting site was created as part of a Jamaican iguana Cyclura collei head-starting programme, numbers of nesting female and hatchling iguanas increased over 23 years. Results were not statistically tested. Twenty-three years after the start of a Jamaican iguana head-starting programme involving building an artificial nesting site, 321 iguana hatchlings and 63 nesting female iguanas were counted compared to 31 hatchlings and nine nesting females at the start of the programme. Two nests were laid in the artificial nest site three years after it was built. In 1991–2015, Jamaican iguana eggs/hatchlings were collected for head-starting in a zoo and head-starters were released from 1996 (278 total head-starters released, usually 6–8 years old or 1–2 kg). In 1997–2014, non-native mammalian predators (mongoose Herpestes javanicus, cats Felis catus, dogs Canis lupus familiaris and feral pigs Sus sp.) were removed using baited cage traps, snares and leg-hold traps (~1,500 individual removed in ~350,000 trap days over 17 years using 20–300 cage traps). In 2011–2012, an artificial nesting site was constructed 40 m south of the main nesting area. During the nesting season in 1991–2015, nests were checked daily and adult female iguanas were monitored by live trapping, observation and camera traps.

(Summarised by: Katie Sainsbury)
Breed reptiles in captivity: Lizards

A replicated study in 1991–2015 in seven zoos in Jamaica and the USA (Wilson et al. 2016) found that Jamaican iguanas Cyclura collei bred in captivity, though most females laid infertile eggs each year. After 24 years of a captive breeding and head-start programme in one Jamaican zoo, five Jamaican iguanas hatched successfully, of which three were released into the wild and two died prior to release. No breeding took place in zoo exhibit cages. After 19–21 years of a captive-breeding programme in American zoos, 73 iguanas hatched successfully. The first hatchling emerged after 6–8 years, but died. Twenty-four hatchlings emerged after 10–12 years and 48 hatchlings emerged after 16–20 years. The authors reported that Jamaican iguanas were less likely to breed in captivity than other captive Cyclura spp. and that in the USA zoos, almost all female iguanas laid infertile eggs annually. In total, 617 Jamaican iguanas were transferred to one zoo in Jamaica (593 individuals in 1991–2015) and six zoos in USA (24 individuals in 1994–2009, see original paper for details) as part of a head-starting and captive-breeding programme.

(Summarised by: Katie Sainsbury)