Herons are also known as "shitepokes", or euphemistically as "shikepokes" or "shypokes". Webster's Dictionary suggests that herons were given this name because of their habit of defecating when flushed. The terms "shitepoke" or "shikepoke" can be used as insults in a number of situations. For example, the term "shikepoke" appears in the 1931 play Green Grow The Lilacs, and in the 1943 musical play Oklahoma!.
The 1971 Compact Edition of the Oxford English Dictionary describes the use of "shitepoke" for the small green heron of North America (Butorides virescens) as originating in the United States, citing a published example from 1853. The OED also observes that "shiterow" or "shederow" are terms used for herons, and also applied as derogatory terms meaning a "thin weakly person". This name for a heron is found in a list of gamebirds in a royal decree of James VI (1566–1625) of Scotland. The OED speculates that "shiterow" is a corruption of "shiteheron".
This is tenuously related to the previous post about "astonishment," btw; I once wrote a (rather bad!) poem about Shetland that appears to have had the side-effect of convincing Alan that the heron's default expression is one of astonishment. For what it's worth "heron" derives from O. Fr. "aigron" of which "aigrette" -> "egret" is a diminutive. Reminiscent of the situation with rillettes discussed in a Richard Wilbur poem:
rillettes. hors d'oeuvre made up of a mash of pigmeat, usually highly seasoned. Also used for making sandwiches. The Rillettes enjoying the greatest popularity are the Rillettes and Rillons de Tours, but there are many Rillettes made in other parts of France.
rillons. Another name for the Rillettes, a pigmeat hors d'oeuvre. The most popular rillons are those of Blois.
-- A Concise Encyclopedia of Gastronomy, ed. Andre L. Simon
Rillons, rillettes, they taste the same,
And would by any other name,
And are, if I may risk a joke,
Alike as two pigs in a poke.
The dishes are the same, and yet,
While Tours provides the best rillettes,
The best rillons are made in Blois.
There must be some solution.
Does Blois provide, do you suppose,
The best rillettes de Tours, while those
Now offered by the chefs of Tours
Are, by their ancient standards, poor?
Clever, but there remains a doubt.
It is a thing to brood about,
Like non-non-U, infinity,
Or the doctrine of the Trinity.