PLEASE NOTE
http://thomaschen.freewebspace.com/custom3.html where much of the groundbreaking research was carried out by Mr Philip Tom. The article notes a fashion in Chinese swords and close ties with sword influence going both ways. Swords made in Beijing were exported to India after 1761 . Further ..a common description amongst Chinese sword design was the pistol grip which is essentially the same as the bird head or parrot head hilt. Note also the practice of cutting grooves in the blade and inserting pearls which roll up and down the grooves; This is a direct copy from Indian blades of that form.
Shown in addition below is the trend in Indian blades; both sword and dagger, of decorating the throat with a cartouche done in Koftgari form but that in the project sword this is of Tunkou style essentially a reinforcement plate giving support to the hilt and enabling a tighter fit for the blade into the scabbard....something koftgari design does not do...nor was it designed to.
Given that in the late 1700s Chinese swords were exported to India it stands to reason that the Tunkou was in fact part of this design imported on these weapons but turned the other way...perhaps to satisfy Indian taste from purely an aesthetic viewpoint as it looked better? See thye Chinese form below.
Regarding the pistol grip hilt which was a Chinese ingredient it is commonly seen in Indian hiltsb although the6y a4re no slouch when it comes to
Zoomorphic hilts...The Indian parrot hilt may by now be a mixed and morphed design though birdhead hilts may go back further in Indian style and it ma6y be simply co incidental. Non the less Chinese pistol grip hilts were common during the period and as a note to the margin of this interesting design.