Measuring success of a reintroduced population of the American burying beetle (Nicrophorus americanus Olivier) to Nantucket Island, MA

The American burying beetle (Nicrophorus americanus) is a federally listed endangered beetle and since 1993 multiple organizations have collaborated to reintroduce this species to Nantucket Island, Massachusetts, USA. We present evidence that despite very successful reintroduction methods, the reintroduced population is not self-sustaining and requires human assistance for long term maintenance. Beetles were reintroduced from captive stock and each year we augmented the population by trapping wild beetles, pairing males and females, and supplying the pairs with carrion. Long term monitoring of this population has shown that, when provided with carrion, N. americanus on Nantucket have an over winter survival rate of 15 % and a reproductive success rate of 54 %. After seeing the number of beetles captured between 2007 and 2011 double, we modified protocols to determine if the established population would be self-sustaining and we have seen a drastic decline. We suggest that a lack of natural carrion is the main reason for this decline.