Around the Island

Mashomack Musings: No otters but our otters

At a time of year when it seems like all living things have hunkered down for winter’s coldest months, there’s evidence around of the once-absent American river otter (Lontra canadensis) — but you may need to look a bit closer.

The species underwent a precipitous decline in the 1800s, due to the fur trade. The thick pelts that make this semi-aquatic mammal ideally adapted for surviving in cold water and cold temperatures enticed trappers and traders, across North America and Europe.

But there’s good news for otter numbers on Long Island. Once thought to be extinct here, otters have made a nascent comeback in recent years. Local wildlife biologist Mike Bottini has been studying the otters’ numbers since 2008 and uses evidence such as latrine sites — yes, where otters “go to the bathroom” — otter tracks and trail cameras to determine the animals’ whereabouts.

Mashomack Preserve is one of a series of study sites on Long Island where Mr. Bottini has found evidence of the otters’ return. Their comeback and movement across Long Island can be attributed to strings of protected rivers, lakes and ponds that act as wildlife corridors, allowing otters to travel and access new habitats.

As the months progress from autumn to winter and food availability changes, otters shift their diet from amphibians and shellfish that are hidden and inactive in colder months, to more readily available prey such as finfish and hibernating turtles.

And while the otters’ budding return is heartening, it may not be an easy one, since threats such as poor water quality impede the animals’ recovery.

Otters’ favorite food sources acquire toxins and pollutants in the aquatic environment and those pollutants accumulate up the food chain. These poisons can negatively impact otters’ fitness and overall survival.

Yet another reason for keeping our environment safe and clean.

Meanwhile, next time you’re out and about during these winter months, keep an eye out for tracks, scat, and other evidence of Long Island’s comeback kid, the American river otter.