Reproduction

How does the black-crowned night heron produce its young?

Their nest is built in a tree or shrub. It is a flimsy platform formed from sticks. They will nest in colonies made up of similar species along other herons, egrets and ibis. At the colony each tree may support up to 12 birds.

Males will make use of the same nest year-on-year regardless of whether they mate with the same female.

To attract a mate a male will create a hiss. He also bows and raises his feather plumes. Newly formed pairs will groom one another and engage in mutual billing.

Once mating is complete the male will begin to present sticks to the female.

A female will deposit between 3 and 4 eggs though as many as 7 have been recorded. The eggs are colored pale green but fade in color as they are incubated.

Both parents are involved in caring for the young. They will regurgitate food for the young. They first move around in the nest at 4 weeks old and can fly by 6 weeks old. They begin to travel with their parents soon after this.

These birds may interbreed with the closely related rufous night heron to produce a hybrid.

Other birds may sneak chicks in to their nest and the pair will raise these as if they were their own.

Sexual maturity is reached by three years old around the same time they develop their adult plumage. Until this time they will have gray-brown feathers on the head, chest and underside. This may be streaked with white.

Behavior

What does the black-crowned night heron do with its day?

These birds are as their name suggests active at night or dusk. Their vision is well adapted to help them see during reduced light conditions. They may move to being active by day during the breeding season or if the weather is unusual.

When not active they will roost in a tree.

Much of their foraging is undertaken on their own but they will nest in a colony.

The vocalization of these birds is a harsh call which is similar to that of a crow.

Animals which live in the North of the range will be migratory moving around based on the weather.

Credit: Public Domain

Predators and Threats

What is impacting the survival of the black-crowned night heron?

If chicks are disturbed by a predator they will regurgitate their food.

Numbers of the black-crowned night heron are decreasing. The total population is estimated at between 570,000 and 3,730,000.

They are facing threats such as drainage or destruction of wetlands in their range. These animals are also affected by pesticide. Contamination has been caused by some substances in their environment and can cause genetic damage to the chicks.

In some areas of their range these animals are taken for food and use in traditional medicines.

Quick facts

In parts of their range they are known simply as the night heron. Across their range these birds may be known as some variation on the word "quark."

Their scientific name, Nycticorax, means "night raven.'

Four subspecies of the black-crowned night heron are recognized.