I’ve come to Bombay Hook, the National Wildlife Refuge at the midpoint of the Delaware Bay, hundreds of times, but I’ve never seen it look like this. As we turn onto Wildlife Drive, it’s clear that Raymond Pool – normally a distant shimmer of water – is no longer a pool, with all that connotes about a small, confined body of water, but a large lake that laps at the very edge of the road. Standing amidst the prairie grasses, as if to confirm that land has been replaced by water, is a heron, hunched among the swaying stems.

No - wait – I see a flash of red: it’s not a heron, but a crane, and when I raise the binoculars, I see that yes, YES, it’s a Sandhill Crane, and in fact there are two of them, striding out now into more open water. We’ve seen them at the Refuge before, but usually they’ve been standing on grass at the back of Bear Swamp, and while I understand that in Florida they stroll across suburban lawns, my memories of them are from wet prairies and wetlands in the Upper Midwest. Today, they look quite at home in the water.

We follow the road around to the other side of Raymond Pool, hoping to see hundreds of dabbling ducks – pintails, shovelers, wigeon, green-winged teal – tails up and heads down as they feed on underwater grasses. Instead, the pool (now lake) is empty from shore to shore. Finally, we see a set of ripples that mark the plunge of a diving duck, and after a few minutes two ducks surface: buffleheads, the male dramatic in purple-black and white, the female a drab brown. Buffleheads are so buoyant that at the end of a dive they seem to pop out of the water like a cork out of a bottle of champagne, exuding cheerfulness. It’s odd, though, to see them here; normally they are across the road, in the fast-moving current of the deep tidal channel that connects to the Leipsic River and the Delaware Bay. That’s when I realize that the water in the pool is deep, much deeper than usual, too deep for the dabbling ducks to be able to reach the bottom-growing grasses. Those birds have fled for shallower water elsewhere.

On the saltwater side of the road, a heron stands huddled, his toes gripping the slippery mud, nearly in the water; it is approaching high tide. He must be waiting out the tide, dreaming of the moment when he can step carefully into the now-shallow water in pursuit of fish. Herons seem able to remotely sense water depth, never stepping into water that would cause their tail feathers to get wet. This one has a long wait ahead. “Poor heron”, I say, “he must be grumpy”. “Grumpier than usual”, my partner replies, because the heron’s prehistoric appearance and cantankerous “G-r-r-r-onk-k-k” calls suggest constant displeasure.

Continuing along the road we come to Shearness Pool, where water is nearly to the top of the embankment that separates the pool from the road. A few disconsolate mallards swim through the cattails. A wide watery vista – “Lake Shearness”, I mentally christen it – opens before us, its flatness punctuated by dozens of muskrat lodges which rise like small volcanoes above the water’s surface.

And then we see that every muskrat lodge has been claimed by avian refugees. Here, a pair of Canada Geese are sleeping on the roof of the muskrat’s reed house; there, a group of mallards is preening atop a haphazard bundle of sticks; and in the further distance a heron stands alert on a cattail platform, like a sentry on a watchtower.

As we drive on, we see more herons on post. There must be some hierarchy among them, for it seems the tallest birds are on the highest lodges. The one closest to us – perhaps a young bird – has found accommodation on a rickety pile that rises only a few inches above the water. He shuffles, stretches, scratches his beak with one long toe. Judging from the number of people at the side of the road, phones raised in his direction, he’s been there for some time. Perhaps he’s tired of being photographed, because as I raise my camera he steps down. Water closes over his tail, and while he maintains a stoic expression, he emits a startled “Gronk!”. That water was ice not long ago.

Like the herons, I am out of sorts. Seeing the Refuge in this half-drowned state, I realize that what I love most about it is the intermixing of land and water, the complex mosaic of mud, marsh and tidal channels, the way the landscape changes so dramatically between high and low tide. I imagine there’s an explanation for all this water – El Nino, perhaps, which brings wetter winters to the southeast coast. Just as there was an explanation for the parched dryness of this place two summers ago, when the parched pools shrank to mud puddles. Too dry, too wet, rarely just right: is this our future?