At the end of March, a spectacular, summer-long show begins along Wyman Park Drive and the west entrance to Druid Hill Park in the heart of Baltimore. It is the song and dance of the yellow-crowned night herons, an uncommon bird that has taken up residence in the Jones Falls.

Grab a seat at orchestra level, on the James Rouse platform overlooking Round Falls, a spectacular sight in itself. There, you will see several nests. Early spring is nest-building time, where the male brings home a stick, puts it down, and the female decides to redecorate. Then it will be mating time, when the males “display,” extending their necks and stretching out their feathers in an elaborate courting dance.

A balcony perch will do nicely, too. Look just below the bridge at the new Jones Falls Trail, and you’re at eye level with the yellow crowns. You’re close enough to tell that a juvenile bird hasn’t yet grown his bright yellow top, close enough to see the soft blue color of the eggs.

Many a runner and biker have stopped here to catch a breath and a bit of the spectacle before logging the rest of their workout. Workers from the nearby Stieff Silver building, which has been renovated to include an outpost of Johns Hopkins, sometimes take their lunch by the bridge. And some people come in the morning and watch all day, not wanting to miss a moment.

Among herons in the Chesapeake Bay watershed, the yellow crowns are the most uncommon to see. It’s easy to spot a blue heron. Their long neck and dinosaur-like appearance makes them unlike most other birds; they love water; they are capable of staying still for long periods of time; and many stay in the area all year.

Black-crowned night herons are also around, fishing on the Eastern Shore and often visible around Kent Island.

But the yellow crowns are rarer, and are listed as threatened and endangered species in several states. Their preferred habitat is wetlands, and coastal development has pushed them out of states where they were once common, like New Jersey.

In Baltimore, the birds don’t appear bothered by a light rail train that whizzes by their nest every 15 minutes. They put up with the glut of trash in the Jones Falls, the curious bikers and hikers and the constant vehicle traffic overhead.

That doesn’t surprise Judy Wink, the ornithologist who directs the Chesapeake Bay Environmental Center in Grasonville.

“Birds are never fazed with stuff like that — they know instinctively their safety is in flight,” Wink said. “I’m glad that they have made the adjustment to live in close proximity to people. And there is an adjustment to be made.”

Why they chose Round Falls is obvious to Wink: Location, location, location. The waters are filled with the fish and crustaceans they feed on. The nests are in a protected area — visitors can look but can’t touch. And the view stretches over the falls to the downtown skyline — unmatched at almost any price.

When they chose it is more of a mystery. Birders have reported seeing the nests since 2010, when it’s believed they moved to Round Falls from a location a few blocks away in Stoney Run.

“Something happened, some kind of storm, and for some reason, it became unsuitable,” said Carol Schreter, conservation chair of the Baltimore Bird Club. “And basically, after that, they moved a little closer to the harbor.”

Anytime after April is a good time to visit the falls, Schreter said. She particularly enjoyed going to Round Falls for a Klezmer concert, which the birds watched as well. But her favorite time, she said, is July 4th weekend.

“That’s when the young have left the nest and are feeding around the sides of the stream,” she said. “I always thought that birds, once they fledged, had no reason to return to the nest. But these birds do. They come back throughout the day to get some food.”

Yellow crowns practice egalitarian parenting. Males and females take turns sitting on the eggs and gathering food.

In early April, there were six nests at Round Falls. Wink said yellow crowns, unlike blue herons, do not always nest in colonies.

Photographers have flocked to the spot in recent years. Dave Lychenheim and John Maloney, both noted for their bird photographs and specifically their Conowingo eagles pictures, have been frequenting the area.

But perhaps no one visits as often as George Williams.

Williams, recently retired from General Electric, heard about the birds from a friend. He was neither a birder nor a photographer at the time; just a man interested in observing nature. It took him three hours to find the birds. But once he did, he was riveted.

He loved to watch the mating display, and come back the next day to see an egg. He loved the way the female bird judged the sticks her mate brought to the nest, and how she moved them around until satisfied. He loved it when a little girl told him that the birds’ feet turned pink when they were ready to mate, and then he got to see it for himself a few days later.

Williams, a career planner, began recording his information in a spreadsheet, and he’s shared the information with others who track the behavior and habitat of birds. His information has become reliable.

“If you call me and say, ‘George, when’s that egg going to hatch,’ I can tell you the day, but maybe not the time,” Williams said.

As he watched the birds, Williams taught himself photography and began capturing some of the most iconic heron images. He has named one of his favorites “bad hair day.” It shows a surprised-looking chick with a spiky mane. One of his photos on Flickr was viewed 61,000 times, he said.

The birds will be around until August, when they migrate to Alabama, Florida and other states around the Gulf of Mexico. And, Williams said, he’ll be there, too, watching the show to see — and record — what happens next.