Category Archives: Atlantic Seashore

Low Tide Life: Atlantic Plate Limpet

Photo of Atlantic Plate Limpet

Along the New England coastline, the only limpet who spends time in the intertidal zone is the Atlantic Plate Limpet (Testudinalia testudinalis). Also known as Tortoiseshell Limpets, these marine snails are typically no more than an inch long, so spotting them requires up close exploration.

Photo of Atlantic Plate Limpet

I've occasionally encountered them while winkling at low tide in and around rocky tide pools. These snails prey on red algae; Atlantic Dogwinkles are among their predators.

Photo of Atlantic Plate Limpet

Low Tide Life: Northern Moon Snail

Photo of Northern Moon Snail

Back in August, while wading in knee-deep water at a local beach, I noticed dozens if not hundreds of Northern Moon Snails (Euspira heros) slowly plowing through the sand. Having been familiar with their shells (empty, washed-ashore ones, that is) for years, I was thrilled to find some occupied dwellings.

The almost transparent bodies of Northern Moon Snails appear much too big for their shells, but as I experienced first hand, when picked up, individuals push water out of their shells and bodies and manage to squeeze into their nearly round homes without much trouble. A perfectly sized, flat operculum serves as the snug door a snail shuts to complete this marine magic trick.

These mollusks live in intertidal and, more commonly, subtidal waters along the New England coastline (and elsewhere) where they seek out meals in the form of Atlantic Surf Clams and other shellfish.

Bonus quiz: Find and identify the other mollusk in one of the following photos.

To view the following images in full-size, click here.

Low Tide Life: Smooth Periwinkle

Photo of Smooth Periwinkle

Smooth Periwinkle (Littorina obtusata) is a small mollusk of the New England coastline who lives in association with Knotted Wrack, Bladder Wrack, and other types of marine algae. Smooth Periwinkle's nearly flat spire is distinctive among local periwinkles. Most of the individuals I've noticed have been yellow (another common name for this species is Northern Yellow Periwinkle), but shell color is variable, and may instead be red, brown, green, or multi-colored. To learn more about this mollusk, check out this species ID card offered by the Gulf of Maine Research Institute.

To view the following images in full-size, click here.

Sorting Sparrows: “Ipswich” Savannah Sparrow

Photo of "Ipswich" Savannah Sparrow
"Ipswich" Savannah Sparrow | Biddeford Pool, ME | 3 Oct 2016

Savannah Sparrows breed in grasslands throughout much of Canada and the northern US, and winter for the most part in coastal and southern US and Mexico. One distinctive subspecies of Savannah Sparrow, which breeds almost exclusively on Sable Island in Nova Scotia, Canada, is the "Ipswich" Savannah Sparrow, or "Ipswich" Sparrow, for short.

Due to morphological differences like their larger size and sandy gray plumage, this subspecies was formerly thought to be a separate species, though current taxonomies now lump this form with the browner, slimmer mainland types of Savannah Sparrows (see photo below). Outside of the breeding season, "Ipswich" Sparrows can be seen in coastal habitats throughout the eastern seaboard, places where being the color of sand can be a distinct advantage.

To view the following images in full-size, click here.

Coastal Crabs: Hermit Crab

Photo of Hermit Crab

While looking around a nearby beach at low tide for living Northern Moon Snails, I came across a slew of Hermit Crabs re-purposing the shells of the species I was seeking. Instead of growing protective carapaces of their own, these crafty crustaceans prefer the rental model, trading in their mobile homes for a larger version when their personal needs and shell availability coincide.

Photo of Hermit Crab

According to Kenn and Kimberly Kaufman's Field Guide to Nature of New England (2012), there are at least 5 species of Hermit Crabs in our area. The individuals shown here are Long-clawed Hermit Crabs* (Pagurus longicarpus). This species has a roughly cylindrical right claw which is larger and longer than the left.

Photo of Hermit Crab

*Thanks to Aaron Hunt (an editor at the Bug Guide) for confirming my tentative identification.