Furniture nomenclature is entirely too flexible. If you do an image search on the phrase birdcage chair, you get something like this:
or even this:
Search for antique birdcage chair and you get this:
The antique chairs are all different. Honest.
The antique birdcage chairs (also known as bird-cage chairs or bird cage chairs) are called square-backed Windsor chairs by Nancy Goyne Evans in her definitive book on American Windsor chairs entitled American Windsor Chairs. If not the definitive book, it is certainly is the biggest at 13″ by 9.5″ by 2.5″ and 741 pages. I could not find the phrase birdcage chair in the book. At least not in the index.
My first chance to examine one of these chairs was while visiting Elia Bizzarri, famous local Windsor chair maker. (He’s done two episodes of The Woodwright’s Shop with The Roy.)
And this is his reproduction chair:
While in his shop admiring the chair, he showed me the interesting bit of joinery. The top rod is joined to the vertical rods with what looks like a miter joint. It’s actually a through tenon with a little chisel work to round things off and complete the deception.
This has been true of the 20 or so chairs I have seen. Then I saw my 21st. The builder apparently didn’t know much about making these chairs. He used the wrong joint.
For more reading about contemporary Windsor chairs and their makers see the Windsor Chair Resource site.
Nancy Goyne Evan has an online article pertaining to the terminology associated with vernacular seating furniture in the eighteenth and nineteenth centuries called Frog Backs and Turkey Legs: The Nomenclature of Vernacular Seating Furniture, 1740–1850.
All this furniture stuff is just too confusing…