I think they were supposed to be some species of quail or grouse, but certainly not bobwhite or ruffed grouse. Definitely not turtles though, although you make a good point that they look like turtles walking upright...






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I am not sure but is that what the extinct flying turnip looks like on the ground.

I love that gun!

There were clearly a LOT of odd looking, and now extinct, species of game in the Meriden area at that time.

I’m pretty sure the flying turnips are supposed to be ducks. The closest looking game bird species that I can find to the walking turtles is the chucker. The engravers must have been going by some kind of pattern because that same bird is on more than one Parker. I took a pic of another example I found in TPS.

Flying turnips and walking turtles ... What gives?

You’d think they could have done better.

Unidentified birds
 

Based on the time period they could be prairie chickens.

You could right: Gun, greater prairie chicken, chucker

Walking turtle

I really like the stylization of early Parker engraving. I know we kid about it, but it is really not intended to be realistic, or even naturalistic (nor did Picasso see people as flounders). I'm sure they are meant to represent Prairie Chickens, as there were still good numbers of them, even if not in New England (the Heath Hen was either gone or nearly so by then). What they really are is adornment on the frame by a craftsman from the long past. No CNC machines here! No Banknote or Bulino engraving -- thankfully!

Heath hen possibly?