Search

Diamondback terrapins (Malaclemys terrapin) inhabit estuarine environments, and adult females typically nest in coastal uplands. Hatchlings emerging from nests overwinter on land and in coastal salt marshes, but the proportions that use each land cover type is not well documented. From 2019 to 2021, we tracked movements and habitat use of hatchlings post‐emergence to determine the importance of upland overwintering sites to a terrapin population in Rhode Island, USA. In late summer and early fall, we attached a radio‐transmitter and passive integrated transponder (PIT) tag (n = 46) or only a PIT tag (n = 132) to carapaces of hatchlings emerging from nests. From August to June, we tracked the hatchlings via radio‐telemetry and a sweeping PIT tag antenna, successfully documenting the fates of 46.6% of them (n = 83). This group included 23 hatchlings that overwintered in the upland, 11 hatchlings that moved to the salt marsh in fall, 46 predated hatchlings, and 3 hatchlings dead from unknown causes. Upon emergence from their nests, 68% of hatchlings dispersed toward water and 32% of hatchlings dispersed away from water. In the uplands, hatchlings typically overwintered within about 2 m of habitat edges. Movement in the uplands peaked from late August to early October, then ceased until hatchlings re‐emerged in late April through early June. To protect terrapins, we recommend limiting the use of heavy equipment (e.g., mowers, tillers) in vegetated uplands near nest sites, and scheduling vegetation management for colder months (Nov–Mar in New England, USA) when hatchlings are inactive. [ABSTRACT FROM AUTHOR]

Bioaccumulation of toxic environmental mercury may affect the vital rates of piscivores such as the common loon (Gavia immer). Although immediate effects of mercury on early development or reproduction can he determined from short-term field studies or dosing experiments, long-term effects on survival for a long-lived species such as the common loon must be discerned from large, long-term observational data sets. We analyzed band-resight and mercury data for 776 adult loons in Wisconsin and New England, USA, from 1991 to 2001 to 1) estimate annual survival rates and 2) investigate the relation between mercury exposure and survival. The model averaged estimate of apparent survival was 0.87, whereas the approximate survival rate (accounting for movement) was 0.92. We found no differences in apparent survival by geographic location or sex and no relation between survival and mercury. Power analyses showed that we were only likely to detect differences in survival ≥3%. Small differences in survival (<3%), which may be important to loon population viability, were unlikely to be detected in our dataset. [ABSTRACT FROM AUTHOR]