His earliest memories were of paints, inks, paper, rubbers and brushes.As a child, Yerka loved to draw and make sculptures.
part of Congress Poland controlled by the Russian Empire.
During his childhood and early teen years he was greatly influenced by his father Julian, a Polish patriot and social activist who introduced him to the world of Romantic literature inspired by the November Uprising.
He cites Hieronymus Bosch, Pieter Bruegel, Cagliostro, Jan van Eyck, and Hugo van der Goes as formative influences on his work.
His subject matter ranges from odd beasts to whimsical landscapes incorporating extraordinary architecture, and includes imagery gleaned from his childhood, such as his grandmother's kitchen.
He was equally impressed with the dramatic art of earlier Polish Romantic painter Artur Grottger.