Night herons hunting at dusk

The long June light holds over Prospect Park Lake until well past eight o'clock. If you are walking the water's edge as the day cools, listen for the harsh squawk that cuts through the evening air. Black-crowned night herons are moving to their feeding stations.

These stocky, thick-necked birds spend daylight hours motionless in the shadows of willows and London plane trees. Their gray and black plumage blends into bark and branch until they seem part of the canopy itself. But as twilight deepens, they descend to the shallows. The night heron's hunting strategy depends entirely on timing. Early summer brings the year's greatest emergence of aquatic insects from the lake bottom. Chironomid midges, mayflies, and caddisflies that have spent months as larvae in the sediment now rise through the water column to transform at the surface. The timing is precise. Water temperature, day length, and lunar cycles all trigger this synchronized emergence. Millions of insects break through the surface film in the span of a few hours.

The herons know this schedule. They position themselves in knee-deep water where the emergent insects are most concentrated. Their hunting technique requires absolute stillness. A night heron can stand motionless for twenty minutes, yellow eyes fixed on the water's surface. When an emerging midge or mayfly breaks the tension, the heron strikes with surgical precision. The thick, dagger-like bill pierces the water and returns with its prey in a single fluid motion. This is not the patient stalk-and-spear hunting of a great blue heron. Night herons are ambush predators, built for explosive strikes in confined spaces. Their shorter legs and compact bodies allow them to hunt effectively in dense vegetation and shallow water where larger herons cannot maneuver. The aquatic insects provide more than just a meal. These emergences represent the lake's most concentrated protein source. A single night heron can capture hundreds of insects during peak emergence hours. The calories fuel not only the adult birds but also their nestlings, which are reaching their maximum growth phase in early summer. Night heron colonies often time their breeding cycle to coincide with this insect abundance. The parents alternate hunting shifts, one bird remaining at the nest while the other works the water's edge.

The relationship runs deeper than simple predation. Night herons help regulate insect populations that might otherwise overwhelm the lake ecosystem. Their selective pressure keeps chironomid and mayfly numbers in balance with the aquatic plants and fish that share these waters. The herons also redistribute nutrients, carrying nitrogen and phosphorus from the water to their roosting sites in the trees above.

Stand quietly at the lake's edge as full darkness arrives. The water barely moves in the still air. Somewhere in the shallows, a night heron waits with the patience that only a predator knows, yellow eyes reflecting the last light as the insects rise to meet the surface.