The common greenshank forages by both day and night, feeding on a variety of insects and their larvae, but also taking crustaceans, molluscs, worms, amphibians and small fish. This species has even been recorded eating rodents and lizards (2) (4). It usually feeds by pecking or probing as it walks through shallow water, or by sweeping the bill sideways through the water (2) (6). An active feeder, it sometimes runs with erratic changes of direction as it searches for or pursues prey (2) (4). Common greenshanks may feed alone, in small flocks, or in larger flocks numbering into the hundreds (2) (4) (7).
The breeding season of the common greenshank runs from late April to June (2). The nest is a shallow scrape on the ground, lined with some plant material. It is built in the open, but is typically placed near to a rock, tree, fence or piece of dead wood, which may help to mark its location (2) (4). The female common greenshank usually lays four eggs, but clutch size can vary from three to five. The eggs are incubated by both adults and hatch after around 22 to 26 days (2).
The young common greenshanks are pale grey with brownish-black markings and a white belly, and fledge at 25 to 31 days old (2). One of the adults, usually the female, may leave the breeding grounds before the chicks have fledged, with the other adult and the juveniles following from three to six weeks later (2) (7). The common greenshank is thought to first breed at two years old, and this species has been recorded living for over 15 years in the wild (4).