Here is the full list of all 16 I commissioned some pigeons achievements.
Complete the game in its entirety.
Find everything hidden in the Post Paper Party artwork.
Find everything hidden in the Curious Cat Companion artwork.
Find everything hidden in the Green Grocer's Corner artwork.
Find everything hidden in the Little Rooftop Garden artwork.
Find everything hidden in the Japan Spring Steps artwork.
Find everything hidden in the Playing In The Park artwork.
Find everything hidden in the Playroom artwork.
Find everything hidden in the Rocking On artwork.
Find everything hidden in the Plants And Paws artwork.
Find everything hidden in the Air Surfing Competition artwork.
Find everything hidden in the Abandoned Factory artwork.
Find everything hidden in the Woodland Stream Houses artwork.
Find everything hidden in the Space Arcade artwork.
Find everything hidden in the Statue At Sunset artwork.
Find everything hidden in the Leaking Kitchen artwork.