Based on the search results, there is no such thing as "erosion birds" in the context of a real animal or bird species. "Erosion Bird" or "Opium Bird" is a name given to an AI-generated picture of a large bird-like creature that is depicted on a snow-covered mountain. It is essentially a meme that became popularized on TikTok in September 2023. The bird is reportedly AI-generated and not real. There are no scientific records or evidence of such a bird species existing.