Did you provide evidence that the property extends up to the roadside in this part of the world.
Being from the UK our boundary would be before the pavement (side walk), I am aware this is different around the world so you would have to show evidence for this location.
This is a garden ornament that is mass produced, as a quick Google search shows, with an example here: Wholesale Metal Rooster Yard Art | Unique Handcrafted Decor | Cuevas Imports There is no indication that this is a public installation. The adjacent homeowner has a don’t let your dog poop here sign in this section, indicating that the homeowners here don’t want others on the property between the sidewalk and the street in front of their properties. But my guess is that Niantic will not remove this.