“Uh! Uh!” cries the mama gull as we stop dead in our tracks on the path. “Uh-uh!”Honest. It’s the clearest avian “Oh, no you don’t!” — or “Just you try it, buddy” — you’ll ever hear. Although a couple of times, it also sounds like “uh . . . oh” — long and drawn out and portending, well, something unpleasant, for sure. The problem is this: The baby black-backed seagulls on Appledore Island have recently hatched, and now the mama birds are keeping, uh, gull-eyed watch over their brown fuzzball offspring (so cute!). And they do not like it — no, not one bit — if you come between them and their little dumplings.Which is what our tour group is about to do, here on the path leading up the hill to the lookout point over the cove. The mama gull is on one side of the trail, and her adorable chick is on the other, and we’re just about to go up the middle until Elisabeth Fischer, the docent leading us, calls a halt.“Oh, this isn’t good,” she says. “Not good. Hmmm.”Well, we’d been warned. “Three things you need to know on the islands,” said docent Eric Schroeder pretty much as soon as we got off the boat, waggling three fingers in the air. “Animal, vegetable and mineral.”Animal, that’s the gulls: “If you get between a mom and her baby, and you see her take off into the air and come circling around, watch out,” he said. “She’s getting ready to poop on you, or maybe even attack.” Yikes! Vegetable: That’s poison ivy. Lots and lots of it, all over the place, so beware. Mineral: That’s the rock that is the islands’ basic component. Watch those slippery boulders!As for the islands? Well, those would be the Isles of Shoals, a cluster of bumpy, barren outcroppings in the Atlantic about nine miles off the coast of Portsmouth, N.H., straddling the Maine-New Hampshire line. Remote and windswept, mostly uninhabited and immensely haunting, they’re probably best-known these days from the 1997 Anita Shreve novel The Weight of Water, about a horrific 19th-century double murder on the island with the coolest name, Smuttynose (sailors approaching its tip thought the algae on the rocks made it look like a dirty honker).Once upon a time, though, the isles were a bustling place. In the 17th century, they were home to fishermen who barely had to lift a finger to pluck the cod from the surrounding waters: They say the fish were so plentiful, you could walk to Portsmouth on their backs.When the fishing dried up, the tourists teemed in. That was in the mid-1800s, when an enterprising lighthouse keeper (on teensy White Island) named Thomas Laighton opened a couple of grand hotels on the isles — one on Appledore and one on Smuttynose (both long gone). A third hotel also sprang up on Star Island.Soon folks were flocking over from the mainland to enjoy the cool, revivifying sea air, and Laighton’s daughter, Celia Thaxter (she was married to Dad’s slightly ne’er-do-well business partner), was busy growing a little cutting garden in front of her cottage to provide decorative blooms for the hotel. Oh, and also being a famous poet whom the great literary lights of the day — Nathaniel Hawthorne, Charles Dickens, John Greenleaf Whittier — would visit at her island retreat. Artists visited also, such as Childe Hassam, who immortalized Thaxter’s garden in numerous paintings and lithographs.It is that garden that’s drawn us here today. Not the original, of course, but the replica on the original site. This was the 1977 brainchild of John M. Kingsbury, the first director of the Shoals Marine Laboratory, a Cornell University/University of New Hampshire field station for marine research on Appledore that also operates public tours to the island.Why Kingsbury thought that people would want to see a faux collection of old-fashioned flowers isn’t clear, but clearly it was a brilliant idea. Our sold-out tour of 35 is full of avid gardeners — and photographers — eager to inspect the famous floral collection. Just call us crazy flower photo people. (The collection, by the way, is only sorta kinda faux; there are a few original plants left, and the rest, all blooms based on Thaxter’s book An Island Garden, are raised from heirloom seeds.)Appledore (once called Hog — good name change) is the largest of the Isles of Shoals at 95 acres and belongs to Maine. It’s also one of the two islands that receive group tours. Weather permitting, there are almost-daily trips all summer out to Star Island (claimed by New Hampshire), where you can sit on the porch at the old Oceanic Hotel and do a walkabout to the church and the cemetery and whatnot.The trips to Appledore are less frequent and highly popular, but my sister, who lives up in these parts, has snagged us some tickets. And even though it’s super-foggy the morning of our tour, we head off through the mist anyway, foghorn blaring. We make it to the island, and the clouds start lifting as we traipse up a path past thickets of beach rose and stop to gawk and coo at the seagull babies. “Don’t worry, there’ll be plenty more everywhere,” says one of our five docents, trying to herd us along, but we think “yeah, right” and keep snapping photos because we know that these are the last such creatures we’ll ever see. Of course we hear about the Appledore House Hotel, the grand 450-guest lodging that dominated the landscape from 1847 until its demise by fire in 1914. It’s hard to picture such a huge structure on this compact piece of land, even looking at the old photos of it in its glory days. The garden isn’t very big, but a rainy spring has rendered it oh-so-lush. The poppies are popping scarlet all over, the day lilies (Thaxter’s own!) are dazzling, the coreopsis is a blinding yellow. We ogle and snap away, bending over the blooms and wandering among the beds that Thaxter arranged by height, so that she’d always know where to look if she needed a tall plant or a short one. I take good note of the hops climbing on the trellis — they’re Thaxter’s, too — but my favorites are the hollyhocks: They have sprung the confines of the fenced-in garden and sprouted inside the stone foundations marking the site of Thaxter’s cottage (burned down along with Appledore House). But now it’s off up the hill and back around to our boat, and that’s when we — well, a few of us, anyway — run into Defender Mom and her chick. After a frozen moment or two, our guide says, “Well, let’s go around.” We reach the top of the hill before we hear the commotion behind us. There’s more squawking from mama gull, some squeals, and then around the bend come our stragglers, flying up the path as fast as their feet will carry them. We can’t help laughing, watching them. I mean, it’s not as if they hadn’t been warned.