What is the meaning of Redshank?

Any of two species of Old World wading bird in the genus Tringa that have long red legs.

Any of species Ceratodon purpureus of moss

Lady's thumb or redleg (Persicaria maculosa), an herb in the buckwheat family.

A bare-legged person; one of the Scottish Highlanders, who wore kilts.

Source: wiktionary.org