Yellow-crowned night herons hunt the summer shallows

The heat builds over the coastal wetlands near Delray Beach, and the water grows thick with summer warmth. In the brackish shallows where salt and fresh water meet, a yellow-crowned night heron stands motionless at the edge of the marsh grass. Its gray body blends with the shadow of overhanging vegetation, yellow crown catching fragments of filtered light.

The heron waits. Its dark eyes scan the murky water for movement. Blue crabs scuttle through the warm shallows, their shells clicking softly against submerged roots and oyster fragments. The summer heat concentrates these crustaceans in the shallow margins where water temperatures rise and oxygen levels shift. What drives the crabs to these edges becomes opportunity for the heron. It steps forward with deliberate precision, each foot placed without disturbing the sediment below.

The yellow-crowned night heron specializes in hard-shelled prey that other wading birds cannot handle. Its thick, powerful bill can crush crab carapaces and extract the meat within. When it strikes, the movement is swift and decisive. The crab disappears, shell and all, processed by a digestive system adapted to break down chitin and calcium. Small fish and fiddler crabs supplement the diet, but blue crabs form the foundation of the heron's summer feeding. The relationship runs deeper than simple predation. By controlling crab populations, the herons influence which vegetation survives in the marsh edges and how nutrients cycle through the wetland system.

Summer brings peak activity to these coastal margins. The water temperature that concentrates crabs also accelerates the entire food web. Smaller crustaceans reproduce rapidly in the warm conditions. Fish move into the shallows to feed and spawn. The invasive green iguanas that have established themselves throughout South Florida bask on exposed logs, adding another layer to the wetland's complexity. Wood storks and great egrets work the deeper channels while the yellow-crowned night heron claims the crab-rich edges. Each species finds its niche in the gradient from open water to dry land.

The heron moves again, one slow step into slightly deeper water. Ripples spread in concentric circles from where its foot touches down, then fade into the dark surface. Listen for the small splash when it strikes, the brief struggle of captured prey. The summer shallows hold their abundance just below the surface, and the yellow-crowned night heron knows exactly where to look.