As Canada falls back into winter, Mauritius is springing into summer. As the temperatures increase, the activity of the wildlife increases as well. On Île aux Aigrettes this shift couldn’t be more pronounced. The endemic species on the island are preparing themselves for the breeding season, with numerous signs observed around the island.
Gecko eggs have appeared overnight in every nook and cranny, always in a pair glued in place by the females. In every key hole and crack seems to be nestled a pair of little gecko eggs. The endemic and brilliantly colored Ornate day geckos found all over Île aux Aigrettes seem to nest in the strangest crevices. A pair of eggs, each no larger than an olive pit, has been found in the first aid kit on the field station, and in a crack in the weatherworn kitchen table under the table cloth. The more elusive and less colourful, but equally striking, endemic Günther’s geckos have also been active with the coming of spring. These incredible geckos are coloured pale grey, green or brown, have dramatically lobed toes, and seem to always be smiling, just like the researcher that showed me some of their known nesting sites with infectious enthusiasm. We spotted numerous pairs of Günther’s gecko eggs in a rocky area on the south side of the island.
The tortoises on the island have also started to breed. While doing my daily passerine work, I came across a white, perfectly spherical and smooth object the size of a tennis ball, which I took to be a rubber ball that had surely found itself onto the island with the child of a tourist. When I lifted it thinking I would take it back to the field station and dispose of it, I realized that it was markedly heavy and dense for its size. Realizing that it was near a tortoise nesting site, I took it back to the field station to pass onto a member of the reptile staff. What I had originally mistaken for a child’s ball was confirmed to be the first tortoise egg of the season. A Mauritian woman who specializes in tortoises with the Mauritian Widlife Foundation candled the egg to determine whether it was fertile and its development stage. She shone a light below the egg in a dark room to illuminate the inside. The egg was found to be infertile, but it was still such an amazing discovery and marked the start of the tortoise breeding season.
With the coming of spring, my daily responsibilities have shifted to searching for nests. The Endangered Mauritius Fody is glaringly obvious when nesting. Regularly individuals perch on a branch with a long blade of grass or a thin twig, and seem to wait for you to spot them before flying on only to perch a few feet further, as though leading you to their nest site and having the graciousness to wait for you to catch up. The male is the one to choose the nest site, and starts to build a nest, but the final say resides with the female. If she is unsatisfied, he may have to build numerous nest attempts before she accepts to nest in one. Once she accedes to a site, then she adds her own personal touch prior to laying eggs in it.
The Critically Endangered Mauritius Olive White-eye is much subtler in its nesting attempts. The nests themselves are correspondingly less obvious to spot. The small cup nests are no larger than a teacup and are equally delicate. The birds spin spider web, blades of grass and feathers together in a concentric, tight, cup-shape to create a beautifully understated nest. As Mauritius Olive White-eyes are monogamous and active pairs are exceedingly devoted they are typically with their partner. Meaning that the primary indication that they may be breeding is the absence of their partner who is busily making a nest, incubating eggs or tending to chicks. Therefore, noting the behaviour of the pair is paramount in determining whether these discrete birds are breeding. Any suspicious behaviour or the lack of a companion is noted at which point the pairs are carefully followed to find the nest.
My upcoming months on the island will be spent combing Île aux Aigrettes for Mauritius Fody and Mauritius Olive White-eye nests to monitor their breeding success, and to band the young before they fledge. It will be a challenge, but will be equally rewarding when the chicks are old enough for the nest to be accessed and to band them!