My gg grandmother was Sadie BYRD/BIRD (her name was Sarah Bird/Byrd but she went by "Sadie". So, if you haven't checked for the name "Sarah" you might try it.

My Sarah (Sadie) Bird/Byrd also has me stumped. She was born in Mississippi ca 1847-1850 and married John Elbert Shelton abt 1869 (either MS, OK, or around Hunt, Tx). John was born in August 1847/48 Alabama (and census records show that both his parents were born in Tennesse and I've found some records that indicate his father may have also been named John E., but not confirmed). John & Sadie's first son was Steve S Shelton (born in Texas - Steve's eldest son's death certificate says his dad Steve was born in Hunt County Texas).

I found some records in Colbert County where the Tuscumbia Post Office ran ann ad in the "North Alabamian, Fri. Jan 6 1837" for people who had not picked up their mail warning them that they would be placed in dead letters if not picked up by January 1st, 1837. This could be our John E Shelton as that would have been about the time he was likely leaving Alabama. Interesting enough, there is also a Wm or DB Fidder? BYRD on the warning of dead letters in that same ad. Which is another reason I wonder if this Shelton and BYRD family left Alabama in that timeframe.

Family lore is that John & Sarah/Sadie met when John was shopping in town with his dad and it was love at first site for both of them(around Fannin or Hunt County Texas we assume near the Red River). Sarah (Sadie) was reported to be full blooded Cherokee (but I don't think there were many full blooded Cherokee by 1847-1850 in Mississippi because most of the full blooded had relocated to Oklahoma by then, but who knows. All records on their children records and census say their mom (Sadie) was born in Missippi. They said Sadie had beautiful long dark hair which she braided.

So, by ca 1869 they were married and settled in Texas (Hunt, McLennan (near Waco), and Caldwell & Gillepie counties). Their last two children were born in Texas ca 1882 & 1885 in McLennan county, their first child born in Hunt County. They had 7 children (5 male; 2 female).

They did Thomas names in the descendents, but I do not know if there are any more BIRD/BYRD's. Sarah/Sadie passed away before the 1900 census and 1890 census are all burned, so I have big gap that henders absolutely tracking better the migration timeline.

Do you know if your Bird family had any American Indian heritage? I am not absolutely sure mine does - have not proved it.

Maybe our lines will cross paths. If you can give me some of the dates and names of who you are looking for (esp those that came to Texas) let me know as I have most of my tree research in Texas (except the migration paths).

The above SHELTON-BIRD-HYATT-GILL-WEST-CHERRY-FOX are the primary surnames I'm tracking on my maternal side and you never know what I might come across with BIRD/BYRD.

Surnames I'm primarily searching on my paternal side are
LEHMANN-MILLER-WALLACE and I just found a BIRD today while finding spouses/marriages, in fact. That's the first BIRD I've come across on my paternal side. My thought was "oh no, not another one". It seems this surname is very hard to track.

I don't have anything immediate that might help with your search, but will print your post and bookmark it in case.
In your Sadie BIRD searches, if you see something that resembles my summary above, please let me know too. Your post caught my eye because of the Sadie BIRD/BYRD.