Why on earth would a bird that flies thousands of miles in search of milder winter weather decide to plop down in Connecticut?

That’s because our state is like Florida to the hooded merganser, which spends most of the year diving for fish in Canadian waters and the frigid Great Lakes.

They’re not the only migratory birds that show up here this season. While kayaking in Long Island and Fishers Island sounds, I’ve seen loons, brants and scoter that hail from as far away as Labrador. Friends and I observed an even wider variety of avian visitors when we hiked at Sachuest Point National Wildlife Refuge near Newport last January: buffleheads, common eiders, great cormorants, greater scaup, black and surf scoters, red-breasted mergansers, long-tailed ducks and harlequin ducks.

I first noticed hooded mergansers at Long Pond on the Ledyard-North Stonington border a few Decembers ago, when the sound of croaking frogs had me mystified. Aren’t cold-blooded amphibians supposed to hibernate?

It turned out that the croaks weren’t from frogs, but from a flock of tiny diving ducks with heads shaped like Roman centurion helmets.

Unlike mallards, canvasbacks, teals and other local dabbling ducks that tip upside down while foraging for food, mergansers dive to grasp small fish in serrated bills. This feature gives the merganser another name: sawbill. My son, Tom, and I hoped to see mergansers a few years ago while canoeing on Sawbill Lake in Minnesota’s Boundary Waters, but it was late in the season and most had flown south for the winter — maybe to Connecticut.

The handful that returned to Long Pond the other day hardly constitutes a mass-migration. Their effervescent energy, though, put resident ducks to shame. While the local mallards hunkered down in protected coves to escape icy, 20 mph gusts, the northern visitors made a beeline for the middle of the lake. Mergansers’ growling croak, by the way, is a mating call. Males also puff up a white crest on their heads, resembling Mohawk hairdos.

I watched them dive repeatedly and pop back up for more than an hour the other afternoon, until the sun began to set and I headed indoors. Who knows — maybe they kept at it all night.

Meanwhile, a pair of nearby domesticated Pekin ducks seemed just plain lazy. They loitered next to a house, where a woman feeds them every day. If she doesn’t hop to it first thing in the morning, they quack impatiently.

The local Canada geese are almost as indolent and insolent. I miss the days when they migrated — their late-night honking while flying south in late fall and back north in early spring had been a welcome lullaby.

Now most of these ungainly birds hang around all year, quickly wearing out their welcome. They like to waddle slowly across the road, oblivious to cars and school buses. Canada geese also like to hang out on the pavement, hissing at pedestrians and bicyclists who stray too close. Worst of all, they are prodigious poopers.

Why can’t they be more like hooded mergansers — spend a few months here, and then take off?

On the other hand, I’m delighted that more bald eagles are becoming year-round residents. A few years ago, they only showed up on the Lower Connecticut River at the start of winter. Now, quite a few of the raptors, our national symbol, have become fulltime Nutmeggers.

They join a wide variety of birds that live here 12 months of the year: woodpeckers, crows, ravens, jays, chickadees, nuthatches and cardinals, to name a few. Even robins, once thought to be a harbinger of spring, often spend all winter in Connecticut.

The mergansers likely will stick around until March or early April, when they’ll begin winging their way back north. By then, birds that flew south last fall should be returning, including redwing blackbirds, osprey, swallows and hummingbirds.

No matter the season, there’s always a bird in the air.