Ok so this piece is not terribly old from what I can tell. Looks like a seam line going up it and that combined with "waviness" of the texture leads me to believe it was made using a wet plaster mould(possibly wet wood mould but I doubt it). This could also be the reason for the discoloring on the lip; which is either plaster dust, or where a waxy tool touches the glass when it was really hot on the reheat of the neck, or least likely from the looks is where it cracked and was refused together. the beak is impressive if its part of the mould, but most likely pulled out later in the process before breaking off the blow pipe(nearly impossibly to get something that long and thin to blow in a mould. If it was puntiled it was directly in line with the bottle neck on the birds breast. Could have been cold worked and polished away if it was puntiled(carefully looking for a slightly different surface there could give it away. this piece could also be made from boro silicate glass on a torch, which would be a slightly different but similar process, and this a real possibility looking at the thicknesses of the piece. this is no older than 1960s most likely though from with in the past 20 to 30 years