The phrase "as a heron" is correct and usable in written English.
It can be used in contexts where you want to draw a comparison or illustrate a characteristic associated with a heron, such as gracefulness or stillness.
Example: "She stood by the water's edge, poised and silent, as a heron waiting for its prey."
Alternatives: "like a heron" or "in the manner of a heron."
A gray post woke up as a heron and took off.
He was 50, Dutch, a marathon runner, as graceful as a heron.
Stalking up a tidal channel with a spear over his shoulder, he is "as flexed and focused as a heron".
The sun bittern stalks insects as a heron stalks fish, stealthily approaching its prey with neck drawn in, then grabbing it with a sudden stabbing thrust of the bill.
One is so English, despite many years in Ireland, that Benjamin Black calls her "tall, straight, stately as a heron, with her hoity-toity accent and her shield of impenetrable politeness".
Each piece, designed with the eye and hand in mind, presented a wonderfully refined silhouette — a creamer as stout as a Disney dwarf, a water pitcher as sleek as a heron in flight.
Some of his figurative language has a precision that allows anyone to see what he is describing, as when a heron takes off, "a foldaway construction of struts and canvas, snapping and locking itself into shape just in time to keep airborne".
As he spoke, a heron circled over the choppy Atlantic and swallows darted in and out of holes in the rugged cliffs.
Besides the elephant's main attraction, a vast gallery houses many other giant animals, such as an ant, a heron, and a caterpillar.
Wearing goggles to protect herself from the potentially lethal stab of the heron's beak, Megan carefully allows the bird to spread its wings and take to the air - a tense moment, as the fragility of a heron's legs mean that it's just not possible to "test fly" it before release.
At a viewing point known for the nearby "happy cows" that swim through the river during the summer to reach pasture, we watched as a gray heron was divebombed by lapwings when it got too near their nests.
