Study of structure. Rather featureless species but the photo shows the proportions well: Medium short straight bill, longer legs, and long wings with moderately narrow attachment to body (wider on Ruff). The grayish color is a good hint too. Common migrant in Denmark.
Adult. Villahøj. Arrived today. With experience even a miniature version like this one is identifiable to species. It's the size, colors and the posture, and of course it helps also knowing that now is the time for them to arrive.
Common Greenshank and Green-winged Teal in the background.