If you see Bud Ferris at a Cape Cod beach, he'll likely have his head down, scanning the flats for crab molts or decorator worms. Ferris, a former biology teacher who volunteers at the Cape Cod Museum of Natural History in Brewster, knows there's more to discover at the beach than the plot of the latest bestseller. "It's always fun," he says. "I do it no matter where I am."
You can be a beach explorer, too, by looking down at the sand or up to the sky or into buckets the kids bring back from the tidal pool. The beach is a living thing that changes with the tide, waves, weather, and neighboring ecosystems such as salt marshes and dunes. You might see a flock of black-backed gulls one day; an oystercatcher the next.
Tune in to the wildlife all around you on Southern New England beaches with these notes from Ferris; Bob Prescott, director of Mass Audubon's Wellfleet Bay Wildlife Sanctuary; and Kristy Owen, a biologist and curator of the National Oceanic and Atmospheric Administration's Woods Hole Science Aquarium.
Just because it's common doesn't mean it's dull. The slipper shell, a snail with a body that resembles a slip-on shoe, has an unusual sex life. Ferris says several of the animals will clomp onto each other like spoons, with a female on the bottom of the stack and males on top of her. But, if the female dies, the first attached male conveniently switches sex to become the designated female in the group. You'll find them all over the Cape's south and bayside beaches, often in the wrack line (the line of debris left on the beach by high tide).
On the Cape's south side, you might also find channeled or knobbed whelks. These sea snails resemble small conches but are actually a different species. Even more likely, you'll find whelk egg cases — long strings of white capsules that each held a baby whelk barely a quarter-inch long. Cool fact: According to the state Division of Marine Fisheries, whelks can live up to 15 years.
Look for sand dollars — disc-shaped animals that are in the sea urchin family — along Cape Cod Bay at low tide. Alive, they are brown and covered with velvety hair but when dead, they bleach light gray or white in the sun. One tradition claims the five slits represent Jesus' wounds and the markings represent the Christmas star on one side and a poinsettia on the other.
Fish (and other things that float)
Take a tip from Prescott and pack a snorkel and mask for Cape beaches. "It's not the crystal-clear waters of the tropics, but it's not that murky, either," he says. You might see peanut bunker, juvenile menhaden that are a popular snack for striped bass; olive-color mummichogs; or even a pipefish, which looks a little like a sea horse without the curved tail and hides in the seagrass, Owen says. In protected spots such as Pleasant Bay in Harwich, horseshoe crabs crawl along the bottom.
Keep an eye out for reddish-brown lion's mane jellyfish. The largest known species of jellyfish, they grow to only a few inches in Cape waters and tidal creeks. Their sting can hurt, Ferris says, but isn't fatal.
Each summer, two to three dozen sea turtles — sadly, mostly leatherbacks hit by ship propellers or entangled in fishing gear — wash up between Buzzards Bay and Harding's Beach in Chatham, and along Cape Cod Bay, Prescott says. If you find a leatherback or any other kind of sea turtle, dead or alive, call Mass Audubon's hot line: 508-349-2615, ext. 6104.
Crabs and other critters
It's easy to spot hermit crabs, which inhabit other animal shells and live in the tidal pools. Just look for a fast-moving snail shell. But there are others: The predominant Cape crab is the spikey green crab, an invasive species introduced via ships 100 years ago. Ferris warns that Calico crabs — beige with purplish specks — are not only common but aggressive pinchers. Fiddler crabs live in the mud or sand, depending on type, have an oversized claw, and can feel you coming by the vibration in the ground. And, according to Owen, their holes have little balls of sand around the entrance.
Mole crabs resemble 1- to 2-inch beetles and live in the "swash" line — the area of the beach where the waves wash over the sand. You can find them or their molts by digging or holding your hand under the sand as a wave washes over it. Don't worry, no pinchers.
In the "eewww" department: sea worms. One you might see is the decorator worm, which "decorates" its tunnels in tidal creeks with shells and stones and can extend up to 18 inches under the sand. They also bite the hand that finds them. In the mudflats, you might dig up blood worms, which also nip. Owen is not a fan. "I hate those things," she says.
Many Cape shorebirds — greater yellowlegs, ruddy turnstones, black-bellied plovers — are actually summer visitors, fattening up for long migrations south from breeding grounds near the Arctic to winter homes as far away as South America.
Indigenous nesters include the graceful and aerodynamic terns. Unlike gulls, which float on the water, terns dive for fish. Least and common terns are the most, well, common, but you might also spot the similar looking but rarer roseate tern. Look for terns feeding along the Cape Cod Bay side during high tide or along the shore on Nantucket Sound. Least terns might be the easiest to spot: They are smaller with a yellow bill and white forehead instead of a dark bill and solid black cap. Terns are most commonly seen from mid-July to mid-September when they feast on sand eels.
The most infamous Cape bird might be the piping plover. Along the Atlantic coast they are designated as a threatened species; off-road-vehicle trails in places such as Sandy Neck in Barnstable or along the Cape Cod National Seashore are sometimes closed to protect their habitat. Plovers like sand spits, Prescott says, because the geography is better for camouflage or escape. The young can't fly for 25 to 30 days after they are born, and when predators are around, they run into the grass or freeze in depressions in the sand. Look for them feeding along the tide line; they have a black neck collar.
Scientifically speaking, there is no such thing as a "seagull." Black-backed gulls, herring gulls, and laughing gulls, however, all feed and scavenge along the Cape and Islands. Prescott votes laughing gulls (black heads, dark gray backs) as Most Likely to Steal Your Lunch. "We've seen them where somebody walks away from a picnic and they descend on the picnic and trash it," he says.
Prescott describes the crow-size oystercatcher as a "bird created by a committee." It has a black head and white and brown body, with a yellow eye and a long orange beak. Likely spots include Nauset Marsh and Chatham. ª
These are some of the Cape Cod nonprofits that run guided beach and tidal flat walks for all ages, some of them free. Offerings vary due to weather and tides.
■ Cape Cod Museum of Natural History in Brewster — ccmnh.org; 508-896-3867
■ Mass Audubon's Wellfleet Bay Wildlife Sanctuary in Wellfleet — massaudubon.org; 508-349-2615
■ NOAA's Woods Hole Science Aquarium in Woods Hole — aquarium.nefsc.noaa.gov; 508-495-2001
■ Cape Cod National Seashore Wellfleet — nps.gov/caco/index.htm; 508-255-3421
Susan Moeller is a writer and editor on Cape Cod. Send comments to firstname.lastname@example.org.