The effect of black rat Rattus rattus control on the population of the Antiguan racer snake Alsophis antiguae on Great Bird Island, Antigua

Published source details Daltry J.C. (2006) The effect of black rat Rattus rattus control on the population of the Antiguan racer snake Alsophis antiguae on Great Bird Island, Antigua. Conservation Evidence, 3, 30-32.
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This study is summarised as evidence for the following.

	Action	Category
	Remove or control predators using lethal controls: Snakes & lizards Action Link

Remove or control predators using lethal controls: Snakes & lizards

A before-and-after study in 1995–2004 in coastal forest on Great Bird Island, Antigua (Daltry 2006) found that eradicating black rats Rattus rattus increased the abundance of Antiguan racer snakes Alsophis antiguae. No statistical tests were carried out. The snake population doubled in 2 years after rat eradication compared to before eradication (pre-eradication population estimate: 51 snakes; 2 years post-eradication estimate: 115 snakes) and, although there were between year fluctuations, the snake population remained greater than pre-eradication (population estimates 2–9 years post-eradication: 78–161 snakes). The author reported rat eradication took place on Great Bird Island (10 ha) over three weeks in late 1995. The island was checked monthly for signs of rats after the eradication program ended. In total, 730 bait stations with the rodenticide brodifacoum dispensed in wax blocks were placed in a 10 x 10 m grid across the whole island. Rats were also eradicated from two neighbouring islands. Snakes were surveyed over six weeks in 1995 before rat eradication and annually after rat eradication in 1997–2004. Snake population estimates were calculated using mark-recapture of individual snakes. Rat eradication programme details were sourced from an associated article (Daltry 2006).
^{Daltry J. (2006) Control of the black rat Rattus rattus for the conservation of the Antiguan racer Alsophis antiguae on Great Bird Island, Antigua. Conservation Evidence, 3, 28–29.}

(Summarised by: Katie Sainsbury)