While on a walk around Lake Merritt in Oakland, or along the San Francisco Bay shoreline, you might see the distinctive shape of a stocky Black-crowned Night Heron hunched over near the water or in surrounding trees. These medium sized birds spend most of the day hunched over, sitting nearly motionless and alone. They become more active at dusk, squawking and hunting for fish, crustaceans, and frogs along shorelines, marshes, tidal flats and other bodies of water. Some research has speculated that they hunt at night because the egrets and other large birds dominate them during the day. Adults have striking blue-grey and white coloring, with a long white plume, while young adolescent birds are more subtly covered in brown feathers with small white markings.
The night herons can be found in fresh and saltwater wetlands across the world, except in the coldest regions and Australasia, but habitat loss, persistent pesticide use, water pollution and climate change has led to a decline in populations. Due to the effects of climate change, it is estimated that only 12% of Black-crowned Night Heron breeding range will remain stable in the coming years. In the East Bay, they have become symbolic of the challenges of supporting wildlife habitat in an urban setting.
In 2014, the Black-crowned Night Herons made unfortunate headlines when tree trimmers hired by the United States Postal Service cut down limbs holding night heron chicks and nests in Oakland, prompting public outcry and concern over the viability of the night heron colonies that have existed in the city for over a century. When night herons chicks fall from trees, there is a lack of vegetative underbrush to cushion their fall and their parents are often too fearful of cars and traffic noise to retrieve their young. This episode is illustrative of the challenges that urban wildlife face. Increasingly, species are vulnerable not to their natural predators, but to human disturbance of their nests, breeding and foraging grounds, and habitats.
The community responded creatively, bringing resources to help protect the birds. The Golden Gate Audubon Society has had two annual Chalk Art Flash Mob in Oakland, where local artists drew colorful chalk drawings of night herons and egrets on city sidewalks below roosting herons to raise awareness and spark conversations with pedestrians about the birds. GGAS volunteers, in partnership with the Oakland Zoo and International Bird Rescue, work as docents to help retrieve fallen chicks and educate the public about the birds.
On your next walk along the shoreline, marshes, or Lake Merritt, keep your eyes open for the brooding Black-crowned Night Heron! Together, we are trying to find balance in our urban habitats.
Image 3: Artist Dustin Feider http://www.audubon.org/news/three-fun-ways-people-are-spreading-word-climate-change