Recovering Relics: where do you read that yours is only the 11th found east of the Rockies? There's been more than that found on that side of the USA. But yes, the vast majority are found along the western coast: Columbia River area of OR/WA, and various spots in CA that had mission era influence. Some guys over hear, that specialize in the earlier European contact sites have found lots of those (Go figure, over here, there still wasn't a lot going on by the mid 1820s, so to reach coins and buttons of that era, is a notch of acheivement for us

).
There is unanswered questions as to whether the phoenix buttons found on the east coast started from the west, and migrated eastward, or whether the ship that carried these surplus French military buttons first stopped on the east coast, before coming around to the west coast to their ultimate destination (manufactured goods to be traded for goods along the west coast). Over here, they are deeply connected to being an indian trade item (for trade for furs, food, labor, etc...) yet they also simply show up in areas not exclusively indian sites. (speaking for CA anyhow). In OR/WA they are associated with indian burials, because the indians had ..... for centuries ..... buried their dead with adornments. Once the white man came, this tradition continued, but now, the "adornments" started to be the trade items that were being introduced, of which phoenix buttons must've been traded by the multiples of hundreds, because they were found en-masse on indian burial islands of the Columbia River.
More info can be seen here:
http://www.thetreasuredepot.com/issue3/article4.htm
I think the reason you may have read that yours is so rare on the eastern half of the USA, is that statistics like that are often put forth by archaeologists, based on their own complitations of known examples. And those "known examples" are gleaned from repositories of other known archaeological digs, and what is in museum collections, written works, etc... What the archaeologists don't necessarily know, is the quantities that surface from relic hunters, md'rs, etc....
I have not kept track of the specimens east of the rockies, but from my recollections (even just going by ones posted on forums), it is more than a few dozen. If you want more info on that, I know a fellow who's tracked this distribution for many years, and he'd have an angle on that. Email me at
ttanner777@aol.com and I'll forward that to him. He might like to see the pix of yours, and know what geographic locale yours was found at.
As for value, I've sold some for as little as $25, and others for as much as $300. Depends on the numbers, bird type, style, shape, etc... Obviously a very small niche of collectors, but when a few of them get in a bidding match, they can be fierce
There's a whole lot more that can be said as to why anyone cares about such a curiosity, but it has to do with early finds, early speculations, and their connection to Indian history, French military colonies, and western trading route history (and the mysteries of their distribution elsewhere ads to the allure

)