Great blue heron family reunion at Henrys Fork

Last week while observing some wood ducks and hooded mergansers, a pair of great blue herons flew in with the male landing in the water while the female perched in the top of a cottonwood. The female’s perch was about 80 feet above the water as she surveilled the area before joining the male to hunt for breakfast.

About five minutes after they began catching minnows, two immature herons arrived to join in the activity. One of the youngsters was very adept at catching small fish with its five-inch beak while the other one appeared to struggle. It would follow one of the adults who appeared to stun or injure a minnow so it could catch the fish easier. These were yearling youngsters and will soon be on their own in a few weeks, but I saw both catching their own fish. Maybe the one was just lazy or did not want to get its feathers wet because it had just been to the “feather-dresser” for a new feather styling.

I watched them for over two hours as they hunted, ate, flirted, preened themselves and interacted with each other and with waterfowl, mostly wood ducks. This all happened on a friend’s pond that was created by part of the changing direction of the Henrys Fork of the Snake River in the Egin area in Fremont County.

Five days after this first encounter with the herons, I again went to watch the pond, and the four herons showed up. From the blind I was again entertained by them, only this time I was able to observe one of the adults preening the “powder blue” feathers on its chest.

On their chest, they have some specialized feathers that do not molt, but continue to grow and fray with age. They will comb these feathers with a fringe claw on their feet creating a powder that they apply to their under-feathers. The powder protects these feathers from fish slime and oils.

That is not the only special physical phenomenon that the great blue heron is blessed with. They can also hunt for food during the night because their eyes are equipped with rod-type photoreceptors which enhance their nighttime vision. Their neck vertebrae are specially shaped so they can uncoil their neck quickly to strike fast from a distance.

The great blue heron feeds mostly on fish, but right now south of Mud Lake, up to 20 herons can be seen working the hayfields collecting and swallowing voles. They hear the voles underground, and spear or grab them while they are hiding in shallow burrows.

These large, gangly, pre-historic-looking birds like to nest in colonies called “heronries” in mature trees with up to 100 pair in each. But they can nest individually in trees, willows or on the ground. Many in the Upper Snake River Valley have abandoned the heronries because of the successful return of the bald eagles.

Bald eagles have now started building nests in heronries because the young herons become food for the young eagles. That has happened at Mud Lake, on the Henrys Fork and on the South Fork of the Snake River, east of the South Menan Butte.

Herons are not great nest builders and usually build a platform to lay their three to five eggs on. As the chicks hatch and grow, they compete for space and for the regurgitated food from the parents. This causes many to fall out of the nest where they will become food for the ground animals like raccoons, coyotes and foxes.

As the high water rises on the Henrys Fork, water will spill over into my friend’s pond deepening its level. This family of herons will have to find other places to fish. The two youngsters will be forced out of the family as the adults start nesting, and they will have to find their own grocery store, but until then, they will have a nice handy one to visit for the daily family reunion.

It is time to start looking for the arrival of songbirds and shorebirds in flooded areas as the insects and worms become available. I will also make sure my feeders are full and will put out orange halves for the colorful birds that enjoy fruit. Bald eagles have started sitting on their eggs and the great-horned owls should soon start hatching. Have a great week.