Night Herons Moving into Baltimore and Other Big Cities | WYPR

Night Herons Moving into Baltimore and Other Big Cities

Jul 16, 2020

My wife and I were strolling late at night in Fells Point, near Baltimore’s waterfront when we heard an odd sound coming from the trees in Thames Street Park.

A neighbor of the park, Rob Baumann, came walking along with his dog. He smiled at, what to him, were familiar noises.

“They sound like monkeys – they really do,” laughed Bauman, owner of a real estate data company who has lived in Fells Point for two decades.  “It sounds like a jungle, if you sit out here in the middle of the night and they are active. It’s crazy. It’s really cool.”

As it turns out, the calls were not from primates – but from a rare and growing urban colony of black crowned night herons. About 10 of the birds have built a small city of nests and are raising their young in the park’s trees.  

Night herons are nocturnal fishing birds more often found living and hunting along the fringes of wetlands. They are stocky but distinguished looking creatures – with gray jackets of feathers, white chests, elegant black crowns – but blood red eyes.

The night herons are fascinating to watch, although conspicuous in their uncivilized dining habits. Rob Baumann looked down at his feet, where the herons had dropped several partially-eaten fish onto the sidewalk.

“They’ll take off at dusk, and you’ll see them fly right out to the water. And you see what they come back with,” Baumann said. “Often, you’ll see in the morning a tuft of feathers on the ground, where they must have dived down on a bird or a rodent or something.”

Unlike other herons, black crowned night herons prey on not just fish, but all kinds of animals, including rats, snakes, and even the chicks of other herons.

This cosmopolitan diet is allowing night herons to survive and even thrive amid growing human development. Colonies of night herons are popping up in a growing number of cities, including Baltimore, New Orleans and Los Angeles

Professor Bryan Watts is the Director of the Center for Conservation Biology of the College of William and Mary and Virginia Commonwealth University.

“Yes, they are one of the species that has adapted to city life,” said Watts. “You are more likely to see them in a landfill than a country club. They like those gritty places within the city landscape, or industrial areas.”

Hunting drove down populations of night herons – and many other birds with attractive plumage -- significantly in the 19th and early 20th centuries.  Then the widespread spraying of the pesticide DDT in the 1950’s and 1960’s caused a catastrophic decline of not just herons, but also osprey, bald eagles, and other fishing birds. But all these species rebounded dramatically after the Environmental Protection Agency banned DDT in 1972, Watts said.

Loss of wetlands to real estate development has tamped down night heron populations somewhat since the 1970’s. But today, night heron populations are considered healthy and stable, with roughly 1,000 nesting pairs in the Chesapeake region.

I played my tape of night heron calls for biologist Kevin McGowan of the Cornell Lab of Ornithology and asked him if he could translate the clicking sounds.

“Those are the young herons that are begging for the parents,” McGowan said. “Baby birds of all kinds, when they are begging to their parents, they are really obnoxious.  There has been selective pressure on the parents to make it stop.  It’s like a baby crying.”

Okay, so that’s baby herons crying out for a meal of fish or rats and whatnot.  So then…what’s this terrifying sound? (Sound of weird screech from night heron)

Are they feeding their babies ...demonic pigs?

No, Kevin McGowan’s theory is this snorting sound is just the babies, acting competitively, and vocalizing to bully other herons away from the delicious fish entrails and other tidbits.

“That sounds something like the call that young herons have that accompanies aggressive thrusts at neighbors,” McGowan said.  “It is something like, ‘Food, food, food, food!  I want the food! Not you! I want the food!”

Wanted or not, night herons are our neighbors here in Baltimore. Their crowns are elegant. Their singing is memorable. And their etiquette? Well… Charm City.