Preliminary Assessment of Road Mortality in Chilabothrus exsul, the Northern Bahamas Boa.

The Northern Bahamas Boa (Chilabothrus exsul) is a secretive species of
boid snake that occupies a relatively small range on the Northern Bahamas Bank. Little is known regarding the natural history of this species or its conservation status. As a component of conducting an IUCN Red List Assessment for the species, we quantified road mortality, or the death of individual snakes on roads caused by vehicle strikes, on 2 transects on Abaco Island, Bahamas. We surveyed transects 21 times during sampling sessions in June 2015, August 2015, and January 2016. We found a total of 11 boas over 1379.2 km of transect sampling. This represented an encounter rate of 0.008 boas/km, and an average of 0.006 dead boas per km and 0.381 dead boas per transect survey. This study is the first explicit attempt to quantify anthropogenically induced mortality in West Indian boas, and the first to document significant road mortality in the genus. Our data suggest that roads should be considered a significant source of mortality for the Northern Bahamas Boa, a consideration that is crucial to preparing an accurate conservation assessment and action plan for the species.