Creamy yellow blossoms sat atop the water lilies. Lotus flowers of wedding white with a central blush of pink filled the ornamental ponds. Pickerel weed and its purple plumes fought for space along the edges. And green was everywhere, in every shade, from the palest yellow-green of the aquatic plants to the Kelly green, grassy paths to the olives and jades of the trees and bushes that enveloped us.

To visit the Kenilworth Aquatic Gardens in midsummer is to delve into a Monet water garden, a bold impressionist blend of flowers and foliage floating in peaceful ponds. Summer’s thrum provided the morning’s soundtrack, punctuated by birdsong and the resonant croaks of bullfrogs.

My reverie in this living canvas was interrupted by a darting movement at the edge of a pond. I saw a crow-size heron with a thick neck, compact body and short legs. The green heron (Butorides virescens) was vigorously shaking a small fish. I watched as a moment later, the bird swallowed its prey whole.

At a distance, green herons appear to be all dark. In silhouette, they remind me of a cartoon burglar, standing in a skulking crouch, looking for mischief. This morning’s partly sunny skies, on the other hand, provided great light to see the beautiful color patterns of this handsome bird.

The green heron gets its name from the velvety color of its back, wings and rump. The sides of the face and the powerful neck are a rich chestnut brown that slides down the chest and sides. The lower bill, its base, the eyes and the legs are all bright yellow. A dark cap complements the black of the bird’s impressive, heavy bill. A few white feathers at the chin are repeated in a white central breast patch streaked with brown, which gives way to a gray belly.

The green heron is only 18 inches from bill to stubby tail, and its broad wings reach 26 inches or so. These rounded wings are ideal for navigating in the dense thickets of waterside vegetation that these birds favor.

Green herons arrive every April in the DC area, and they will stay until the end of September. Their breeding range stretches from North Dakota to Nova Scotia and south through the entire Chesapeake watershed to the Gulf of Mexico. A separate Pacific population ranges from Washington State to Mexico.

Resident populations of green herons can be found from Florida to Texas, through Mexico, and down to the migrating birds’ winter range in Central and northern South America.

Green herons can be found in wetlands or near lakes and ponds, like the manmade ones in the Aquatic Gardens. Typically, they fish in very shallow water, sometimes wading in on their short legs.

Their diet centers on minnows and other small fish like the carp that fill these ponds. But they aren’t especially fussy, also eating insects and spiders, snails, snakes and the occasional mouse.

Green herons are one of the few birds that use tools. Like their human counterparts, green herons use bait to catch fish. The birds will drop a small leaf, insect or other object on the surface of the water. As fish rise to investigate, the green heron strikes with lightning speed, grabbing (or stabbing) the fish in its dagger-like bill.

Green herons are widespread and common. In some respects, that’s not surprising. After all, they can find food in a wide variety of wet habitats, and their diets are not particularly selective.

While green herons are listed as a species of “low concern,” their numbers have declined by 1 percent annually for decades. The constant downward trajectory means that today we have one-third the number of green herons that we had in 1966.

Human population worldwide is on a different path, growing at about 1 percent a year. Our burgeoning numbers will grow from 7 billion to more than 8 billion in the next decade. Herein lies the problem for the green heron.

As humans endlessly encroach upon wetlands and turn forests into farms and pastures, birds and other wildlife get squeezed out of existence.

Migrating species like green herons are particularly susceptible to these trends, facing loss of habitat both in the United States and the many other nations where they live part of the year.

The Chesapeake region has a world-class effort aimed at restoration and preservation. But that laudable effort is facing strong headwinds with a national administration that is trying to roll back clean water protections and land preservation efforts.

As I stood in the small refuge tucked into a bustling city, I realized anew that this green heron and all its brethren were at risk in large part because of human actions. And it is up to humans like you and me to change that trajectory.