Black-crowned night heron are nesting near Mud Lake

The attack was on. Four yellow-headed blackbirds chasing a lone heron in the dwindling evening light across the bulrushes and cattails of Market Lake. The blackbird-bombing went unsuccessful, as the black-crowned night heron carried off a blackbird chick for dinner.

Black-crowned herons eat almost anything that comes in handy when their dinner bell sounds — including chicks of other herons. Mostly fish-eaters, they also eat frogs, snakes, plants, rodents, eggs and have even been observed rummaging through garbage dumps. They are opportunistic feeders. But if a stranger has laid an egg in its nest, it becomes the heron’s and it is raised as it is their own.

Their feeding has no manners. Once a victim is located, a quick thrust from the heron’s coiled neck stuns or grasps the prey. Once in the serrated beak, it is flipped into the air and swallowed headfirst, whole; no tasting or savoring — just food. But no indigestion for this bird, as their highly acidic stomach digests bones, scales and feathers creating a white wash of anything it lands on.

This beautiful gray, black and white bird are sometimes hard to see in southeastern Idaho due to their feeding and activities being mostly at night. They can be observed in the evening, early morning, on overcast days or when food is scarce.

The Black-crowned night heron is the most common heron in the world inhabiting every continent except for Antarctica and Australia. In the Upper Snake River Valley, it nests along most rivers, lakes and marshes. Mud Lake and Island Park Reservoir have colonies of nesting Black-crowned nesting on them while Market Lake has a few visiting during the summer.

In areas of the world where the colonies of the black-crowned herons number in the thousands, they are hated by man and bird. In Singapore, large areas have been fogged or sprayed to kill them off because they destroy trees, vegetation and fish farms with their droppings.

Even though they usually hunt and feed alone, they nest in colonies. Their nests are quite crude, being built mostly by the male. During a courtship dance called “snap displays,” the male invites the female to the nest and offers a twig to her. Once a twig is accepted by the female, the marriage is complete, and housekeeping is set up. The male will continue to bring nesting material to the nest while the female is sitting and she will use it to improve the nest.

During nesting on hot days, the eggs are cooled by the adults flying out to get water on their feathers to cool them down. Once hatched, the fun really begins. The chicks are fed a fish, bird, amphibian or plant puree, regurgitated to them from their parents. When approaching the nest, each parent must communicate with the chicks that it is really them or they will get sprayed by the mess they just gave the babes. This is a way to protect themselves from raiding parents within the colony.

With colonies of nesting Franklin Gulls, terns, white-faced ibis and black-crowned herons together at Mud Lake, evening and even some days can be entertaining as they battle to protect their nests.

On Thursday evening, some farmers were swathing their hay. Eleven black-crowned, nine great blue herons, numerous Swainson’s hawks and northern harriers were waiting and harvesting voles and other rodents. I did not see any of the rodents harvested by any of the black-crowned herons.

Right now, one of the best places to watch for these birds are on the road running to the South Boat Ramp on Mud Lake and then take the road that runs along the south side of the lake. The herons are nesting in the willows along the canal and lake and if you are lucky, you can spot one before it flies away.

Have a great week. The young are starting to leave the nests for many of the birds, and predators like weasels, mink and even skunks may be seen as you enjoy the great outdoors.