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Spring 2012

Urban Jungle

The changing natural world at our doorsteps | Illustration and text by Patterson Clark      

June 5, 2012

Black-crowned night herons

Wild wading birds nest at the National Zoo

Every day at 2 p.m., scores of black-crowned night herons collect under a tree near the Bird House at the National Zoo. The night herons, each about two feet tall, gather to compete for freshly killed mice, which zookeepers toss to them. A red-shouldered hawk also flies in from the neighborhood to grab a freebie.

Night herons are capable of finding food on their own, but the zoo uses the mice to create a distraction while some of the larger, less agile captive birds are fed. Otherwise, the night herons would descend into the open pens and steal mice from the fenced-in storks and ground-bound, cranelike bustards.

In early March, night herons arrive at the zoo from perhaps as far away as Central America to build their nests in the trees near the Bird House. They've nested there since at least the early 1970s. It's a safe spot — and there is free food.

Night herons generally sleep during the day and vacate the zoo at dusk, flying off for nighttime feeding excursions at local wetlands, where they fish and hunt for small animals. When night herons return to the nest, they regurgitate some of their catch into the mouths of their hungry chicks, which hatch in April.

By early June, young birds are leaving the nest and are learning from their parents how to hunt — and how to watch for the approach of humans carrying a stainless-steel pan filled with mice. Daily feedings continue through mid-August, when the night herons start migrating to points south.

SOURCES: National Zoo, staff reports

Black-crowned night heron, Nycticorax nycticorax

Nycticorax nycticorax
Adult and fledgling