Mindful that the artist may have granted himself license as to colouration and body shape,
and adding that mine is only a guess, perhaps your small birds belong to the FINCH family.
Found online at a UK birdie site: : Small birds with forked or notched tails, moderately pointed wings, rounded or elongated bodies and round heads, with more or less triangular bills...The bill shape varies according to the principal type of food, from short and rounded to rather long and sharp.
Some species are agile and feed while perching on, or hanging from, plants, .
I have attached three plates from the BALDWIN book—recall that I'm so green at glass that if I walked into a pasture the cows would eat me—as other possibilities, which may or may not be useful.
The fourth attachment is Baldwin's description of the third of three gilt processes. It would seem, from your photo, that your surround shares this characteristic. Due to the text's length, I am mindful that I am stretching the bounds of Fair Use but since I gain ''no commercial benefit'' from doing so, I believe it's OK.
Confession: I sell antiquarian and collectible books: underlining and writing on pages are not concepts I support--unless they are pages in what's become my text book. I was sorting between the three idents for Mr. Root Beer(may be #3) and found the notation about the presence of lavender like several of his oaks leaves.
Moser Artistic Glass ~ Edition Two.
Baldwin, Gary D.
1997: Marietta, Ohio The Glass Press Co.
As early as 1878 Moser introduced enameled and gilded glass imitating Islamic goldsmiths' work and Japanese floral motifs. (p.13)
1875 – 1885: Islamic, Chinese and Japanese style glass produced (p.74)