There is no specific meaning or symbolism associated with a small yellow bird on your window screen. Different cultures and traditions may have their interpretations, but these can vary widely. In general, birds are often seen as symbols of freedom, hope, and new beginnings. The appearance of a small yellow bird on your window screen could be considered a positive sign, bringing a sense of joy, optimism, and brightness into your life. However, it is ultimately up to personal interpretation and may hold different meanings for different individuals.