Why did Sylvia not tell the stranger about the heron?

Sylvia chose not to tell the stranger about the heron because she felt a deep, personal connection to the bird and wanted to protect its sanctity. Sharing the heron's existence could lead to its disturbance or exploitation, which conflicted with her strong sense of loyalty to nature. Additionally, Sylvia's bond with the heron symbolized her own struggles and desires, making it a private part of her life that she wasn't ready to share.