This study was conducted to obtain accurate information on the reproductive ecology of the threatened population of Blanding's turtle (Emydoidea blandingii) in Nova Scotia. In 1994, 1995, and 1996, beaches and roadways in Kejimkujik National Park were surveyed for nesting turtles; all nests observed were covered with wire-screen cages to prevent predation and facilitate the collection of data on incubation and nest success. Nesting lasted from mid-June until early July. In each year, 80% of nesting occurred during a 10-day period in the third and fourth weeks of June. Turtles nested in the evening and predominantly on lakeshore cobble beaches. Site fidelity is high in this population: 73.3% of multiparous females returned to nest on the same beach in all years. No female produced more than one clutch per season, and most females (67.9%) nested less than annually. Mean clutch size was 10.6 eggs. Hatchlings emerge in September and October. Incubation times ranged from 80 to 128 days (mean = 94 days, SD = 11.7 days; n = 26 nests). In 1994 and 1995, most protected nests were productive; that is, 76.4 and 93.3% of protected nests produced at least one live hatchling in 1994 and 1995, respectively. In 1996, only 18.1% of protected nests were productive. Between 50 and 75% of productive clutches contained unhatched eggs and, on average, between 1.0 and 1.2 eggs failed per productive clutch. Total annual egg failure ranged from 26.5 to 94%. In the absence of nest predation, lower temperatures during incubation and nest flooding appear to be major cause of egg failure in this population. More effective means of reducing nest failure and bolstering recruitment must be implemented if efforts to aid the recovery of this threatened population of Blanding's turtle are to be successful.
The early postemergence behaviour of neonate Blanding's turtles, Emydoidea blandingii, was studied in Nova Scotia in 1994 and 1995 to test the hypothesis that hatchlings go to water immediately upon emergence from the nest. At the northeastern limit of the species' range, hatchling turtles should seek aquatic hibernacula to avoid freezing; where emergence from the nest is delayed until late autumn, selection pressure for water-seeking behaviour should be strong. Using pigmented powder that fluoresces under UV light, 78 hatchlings from 12 lakeshore nests and 2 inland nests were tracked for a maximum of 11 days. On the first day after emergence, hatchling movement was random with respect to water. Hatchlings did not orient themselves with respect to slope, vegetation, or nestmates, nor did individuals follow a consistent compass bearing among days. Often trails were convoluted in the open and relatively straight under dense vegetation. Evidence suggests that hatchlings in this population may overwinter in terrestrial as well as aquatic hibernacula.RCsumC : Le comportement de Tortues mouchetkes, Emydoiileu blandingii, fraichement kmergkes des nids a ktk ktudik en ~ouvelle-~cosse en 1994 et 1995 pour kprouver I'hypothkse selon laquelle les petites tortues gagnent I'eau immkdiatement aprtts leur sortie du nid. A la limite nord-est de la rkpartition de I'espttce, les petites tortues devraient thkoriquement se chercher des hibernaculums dans l'eau pour kchapper au gel; la oh I'kmergence du nid est retardke jusqu'a la fin de l'automne, la pression de sklection qui favorise le comportement de recherche de l'eau devrait logiquement etre forte. La trajectoire de 78 tortues nitonates a ittk suivie durant un maximuin de 1 I jours a partir de 12 nids sur les rives et de 2 nids loin des rives, par utilisation d'une poudre pigmentke fluorescente a I'ultra-violet. Au 1" jour de l'kmergence, la trajectoire des tortues ktait alkatoire par rapport a la position de l'eau. Les tortues ne s'orientaient ni en fonction de la pente, ni en fonction de la vkgktation ou par rapport leurs congCnkres, et aucune tortue n'a suivi une trajectoire selon une direction gkographique dkfinie pendant plusieurs jours. Les trajectoires ktaient souvent circonvolukes en terrain ouvert et relativement rectilignes sous la vkgktation dense. I1 semble que les tortues neonates de cette population puissent passer l'hiver dans des hibernaculums terrestres aussi bien que dans des hibernaculums aquatiques. [Traduit par la Redaction]
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