The Long-billed Dowitcher probes mud and shallow water with its long bill to find small aquatic animals.
It has a rounded body and long bill, with black and rusty tones in breeding plumage and gray-brown tones in winter.
On its North American breeding grounds, it nests in wet meadows. During migration and winter, it probes mud for aquatic invertebrates in shallow ponds and wetlands.
It makes a deep cup nest among marsh grasses and mosses near a pond, lined with grass and sedge leaves. The clutch is three to four eggs and incubation lasts 21–22 days. Chicks can walk at hatching, leave once all eggs hatch and feed themselves.
It probes deeply in mud and may submerge its head while feeding. Breeding foods include midges and their larvae, beetles and caterpillars; coastal foods include polychaetes, amphipods and small bivalves. Nocturnal feeding is frequent outside the breeding season.
A long pale eyebrow and white back between the wings occur in all plumages. Juveniles have blackish back feathers with rufous or buff fringes. Nonbreeding birds have gray backs and chests with paler bellies.
An extinction-risk assessment has not been added yet.