Sunday, October 23, 2016

Black-crowned Night Herons at CSU Stanislaus

Black-crowned Night Herons (Nycticorax nycticorax) are somewhat secretive wading birds, preferring to roost during the day and emerge at dusk.  Perhaps surprisingly, a few individuals can be seen around the ponds at CSU Stanislaus.  They are a favorite of mine, partially because they are more commonly associated with remote wetlands than with college campuses, and partially because they always look so perturbed at being discovered (not anthropomorphizing, I promise!)
Black-crowned Night Heron (Nycticorax nycticorax) perched in a Gingko tree.
Not what you would expect: a Black-crowned Night Heron perched in a Gingko tree.  But so it is.  We often see the pair of Night Herons on campus roosting during the day deep inside a couple of Coast Redwoods (planted as ornamental trees in the lawn near a pond), which is also far from typical heron habitat.  Black-crowned Night Herons can be found in both saltwater and freshwater wetlands in California, as well as along streams, ponds and flooded agricultural fields.  They commonly nest and roost in trees or cattail reeds that provide cover and protection from predators.
Black-crowned Night Herons are believed to be monogamous.  Early this past spring, we noticed two herons hanging out together on campus at Stanislaus State.  During the summer, we were excited to discover that they were a breeding pair, and that they had been successful this year, as evidenced by a fully fledged juvenile Black-crowned Night Heron along the shores of Willow Lake.
Juvenile Black-crowned Night Heron, on the hunt.
Hunting along the edge of a pond, the juvenile Night-crowned Heron blends in with its surroundings.  Juveniles will remain cryptically colored through their first winter.
Cryptic coloring of the juvenile Black-crowned Night Heron
The photo below shows how well the juvenile's camouflage works, as the white spots break up its shape and allow it to blend into the cattails along the edge of the pond.
Hunting at dusk, the juvenile blends in with its surroundings.

No comments:

Post a Comment