This hand-painted Bird with Letter Bosch figurine, is from Hieronymus Bosch's painting The Temptation of Saint Anthony.
The inscription on this note in the beak of this birdlike monster on skates could throw a light on the contemplated symbolism. Unfortunately, this text, which is difficult to read, is open to various interpretations, but none of them are proven to be accurate. The postman-like freak is perhaps delivering a letter to the conspiring figures in the hole under the bridge. The funnel on this curious bird's head gives him a preposterous appearance. This headwear is referred to elsewhere as wisdom or absent-mindedness, but that symbolism seems unsuitable here.
This Bosch figurine is one of many available from the National Gallery.