Hakuin Ekaku (1686 - 1769) painted a haiga incorporating an ancient mortar & pestle like this. To his painting he attached the words rendered here in haiku form. (The Japanese is l.r.) Reading the text only is deceptive because this image is not (really) about birds.

The bird form in this painting looks neither like a nightingale or a tailless wren. The nightingale, or Japanese bush warbler ("Uguisu"), is often heard but rarely seen and is sometime referred to as "spring bird."

By contrast, the Japanese name for the Eurasian wren is "miso-sazai." Miso (as in 'miso soup') is a traditional Japanese seasoning produced by fermenting soybean paste made in olden days using the mortar & pestle.