Augury and redundancy

There's a curious sentence in Leland, Etruscan Roman Remains in Popular Tradition (1892), p.344:

"They invented astrology and Etruscan divination, augury, oracles, magic, mythology, and moreover taught men how to make ornate and feigned images of exquisite beauty of kings long passed away, and endowed them with other names." (bold-face mine)

This is the definition of augury. This is the definition of divination.

In what way is augury meaningfully different from divination? In what way are oracles somehow unincluded in the notions of both augury and divination?? Have my reading skills dulled??? Is the LSD catching up with me? Because I could swear that these first three nouns in the above list are reducible to one and that this Victorian-Age writer was trying too hard.

Here's another enigmatic passage I found from
Buckland, The fortune-telling book: The encyclopedia of divination and soothsaying (2003), p.xi

Again, is the author aware of what augury (ie. "the practice of foretelling by means of signs"), divination (ie. "act of foretelling future events") and soothsaying (ie. "the practice of foretelling events") really means and the ridiculous semantic similarities of all these words? His title seems to insist that there's a difference but I'm stumped because the dictionaries are saying something different. Comical stuff!

After Duane on Abnormal Interests mentioned his different understanding of augury as 'bird divination' instead of what I understood to be general omen-seeking of an augur, I came across a bunch of these confusing lines of text in Google. So I wonder, are we all on the same page about the term augury? Are there secondary "niche definitions" lurking about in the crowd that I should be aware of? It seemed to me that Etruscanists are using augury to refer to priestly divination in a general sense while other specialized terms of omen-seeking exist such as auspicy (bird-divination), brontoscopy (divination of lightning and thunder) and haruspicy (liver-divination).

Using augury as a synonym for auspicy on the other hand is simply confusing and, to me, ahistorical. Though I wonder if it has something to do with a long-standing folk-etymology that tries to derive au- in augur from avis 'bird', as is true in auspex, only to be left with an unanalysable portion, -gur. This etymology is certainly a tall tale. Augurs did more than just ornithomancy.