Conducting a reptile census in and around what had once been an ornamental pond

A stump-toed gecko (Gehyra mutilata) fails to escape

Bufo marinus

(Cane Toad)

Cane toads are not common on Coconut Island, probably because of the lack of easily accessible fresh surface water in which they could breed. Individuals are occasionally seen foraging in vegetation. We found five animals trapped in a concrete tank holding several centimeters of stagnant rain water.

Gehyra mutilata

(Stump-toed Gecko)

These geckos are nearly ubiquitous. We found them on buildings, trees, walls, and various other structures, as well as in trees and under rocks, logs, and debris, of both natural and human origin. Occasional individuals were encountered during the day, but most remained in refugia until evening hours. Activity seemed to peak from dark until about midnight, with fewer animals seen in the hours before dawn. The abundance of these geckos on Coconut Island may be attributable to the apparent absence of larger, more aggressive house geckos (Hemidactylus frenatus), which are very common on nearby Oahu.

Stump-toed geckos vary considerably in color and pattern, even in the same individual under different environmental conditions. This may give the impression that one is seeing more than one species of gecko.

Photograph by David M. Nieves

Photographs by David M. Nieves

Lepidodactylus lugubris

(Mourning Gecko)

Mourning geckos were found in all of the same habitats as stump-toed geckos, although they were less frequently encountered on buildings and under rocks and appeared to be more common on trees, especially palms. We found them foraging on trunks throughout the night, but never encountered them during the day, when they apparently retreat under loose bark or into the abundant shelter provided by the trees' fruits and fronds. These geckos are parthenogenetic females, which means that they produce eggs that develop without fertilization by a male. This trait causes them to be very successful colonizers, as only a single individual is necessary to establish a new population. Like stump-toed geckos, mourning geckos vary considerably in color and pattern.

Lampropholis delicata

(Metallic Skink)

These diminutive skinks were common all over the island, and were frequently observed basking on a variety of elevated perches from which they rapidly retreated into vegetation when disturbed. We found them under rocks and a variety of debris, but they also were abundant in cultivated gardens and grassy areas, particularly near trunks of large trees.

Photograph by David M. Nieves

Photographs by David M. Nieves

Ramphotyphlops braminus

(Island Blind Snake)

This is the only snake successfully established on the Hawaiian Islands. Parthenogenetic like the mourning gecko, all individuals are females and are capable of establishing new populations with a single individual. Island blind snakes presumably arrived in Hawaii, and on Coconut Island, in the soil of potted plants. The spiked tail is used as an anchor when burrowing through soil. We found several individuals under rocks. The specimen illustrated is a mature adult.