While land dwellers typically search for signs of spring by looking at the ground for blooming flowers, you’ll usually find boaters craning their necks toward the skies in search of ospreys this time of year—a true maritime sign of spring. Maybe we’re in love with the loud shrills they let out as we pass by their nests atop navigational markers, or perhaps it’s the acrobatic stunt shows they put on while hunting for dinner. Either way, it’s here in Bay Country where one of the densest populations of this fish-eating hawk on earth lives and breeds each year.

Anyone who follows me on Facebook knows that I’m a certified bird nerd. While other people are posting pictures of corned beef, cabbage, and soda bread during St. Patrick’s week, I am looking to sight and photograph those first ospreys to arrive in my portion of the Chesapeake Bay in Annapolis, Maryland. Don’t get me wrong, I love those Irish traditions, but knowing the ospreys are back in town means spring has truly arrived. It’s the Bay Country equivalent of the swallows returning to San Juan Capistrano, and the osprey seemingly always show up here within five days either side of green beer day.

In the Mid-Atlantic, osprey pairs typically arrive in mid to late March, and almost immediately claim a spot to start nest building and mating. Pairs typically mate for life. In areas without sufficient nesting platforms (such as the aforementioned navigation aids), osprey will set up shop almost anywhere that provides a stable, commanding view of the surrounding area. Sometimes that’s a pine tree in coastal forests, but sometimes it’s in odd places such as on top of people’s boats, homes, or cars.

I once even photographed an osprey pair actively nest building and mating on top of a crane that was being used in bridge construction across a local creek. But the fact that osprey often face stiff competition for nesting spots is actually good news. Why? Because they were in serious trouble only 40 years ago, thanks to the outlawed pesticide DDT. Today, populations are booming.

Once the deed is done and the eggs are laid (typically two to four eggs), the pair will take turns incubating them for the next five weeks. A typical successful osprey clutch is generally no more than three birds, even if four or five eggs successfully hatch. That’s primarily due to the fact that once the last egg hatches; the hatchling’s oldest siblings have as much as a week to ten days head start on them.

This means the stronger, more vocal older birds get most of the food brought by the mother, while the younger birds grow weaker and weaker. And like many raptors, older osprey chicks sometimes even seek to kill their younger siblings to take them out of the picture altogether. It’s a morbid example of survival of the fittest at work.

The osprey chicks grow quickly on a diet consisting exclusively of fish. By August, they’re flapping their wings and practicing for first flight. By September, they’re taking their first flights away from the nest, and when the first cold fronts of October arrive, they’re headed south toward warmer climes. Almost all North American osprey winter in an area ranging from the southern Caribbean all the way down to the Amazon River Basin in South America, where they spend the next three to four months. In late January, into February, they start back north again.

If you’ve ever watched an osprey on a morning hunt, it’s quite a spectacle. Once a fish is sighted, the osprey will hover in place for several seconds (that hovering military aircraft, the V22 Osprey got its name for a reason) before diving talons first into the water to grab its prey—sometimes a foot or two under the water. It then flies virtually straight out of the water with its meal, gaining altitude before making a few inflight “shakes” to shed itself of extra water weight.

Once the bird is on its way, it does something quite unique: it situates the fish with its head into the wind to make it more aerodynamic. It can do this thanks to a reversible outer toe that allows it to get a “two talon by two talon” grip on those slippery fish. The poor catch is then taken back to the nest or other roost where it is systematically dissected and eaten with the help of the osprey’s sharp beak.

So, keep your eyes on the sky over the next couple of weeks for the arrival of these remarkable birds. When you see one, you can take comfort that warmer boating weather is certainly on its way.