The least yellowlegs (Tringa flavipes) is a small shorebird in the family Scolopacidae. It is one of the most common and widespread shorebirds in North America and is an important species for birdwatchers to be familiar with. Though it bears a resemblance to the larger and more boldly patterned greater yellowlegs, the least yellowlegs is distinctly smaller and daintier. Its thin bill gives it a delicate look, and its pale legs are long and spindly. In this article, we’ll cover identification tips, range, habitat, diet, breeding behavior, conservation status, and where birders can spot this species.
Identification
The least yellowlegs reaches lengths of 8-10 inches, with a wingspan around 18 inches. It weighs just 1.4 to 2.2 ounces. Its relatively small size helps distinguish it from the greater yellowlegs.
Other identification features include:
- Thin, dark bill with a slightly upturned appearance
- Long, bright yellow legs
- Pale neck and underparts
- Dark upperparts with white stripes on the back and white spots on the wings (seen during flight)
- Frequently bobs tail up and down
In flight, the least yellowlegs displays a thin white stripe on its otherwise dark wings. Its flight style consists of stiff, shallow wingbeats and glides low over the water.
Vocalizations include a soft, musical “tu-tu-tu” call. During courtship, it makes louder “teu” and whistled “tleu” calls.
Range
The least yellowlegs breeds in Canada and Alaska and migrates to coastal areas throughout the lower 48 United States, Mexico, Central America, and South America.
Its breeding range spans:
- Northern Canada from western Alaska to central Quebec
- Northeastern Alaska
During migration, it stops at inland wetlands and lake shores across much of North America.
Its wintering grounds include:
- Pacific, Atlantic, and Gulf Coasts of the U.S.
- Mexico
- Coastal areas of Central America and northern South America
Some least yellowlegs remain as far north as the Pacific Northwest and Northeast U.S. year-round.
Habitat
The least yellowlegs nests in open boreal forests and forest clearings, often near ponds, lakes, or wet meadows.
During migration and winter, it sticks to coastal habitats like marshes, mudflats, estuaries, and shorelines. It also uses inland wetlands including ponds, lakes, flooded fields, and river edges.
Diet
The least yellowlegs eats small invertebrates like insects, crustaceans, and mollusks. It forages by probing into mud and sand with its long bill, feeling for prey. Its bill allows it to snatch up items just below the surface.
Common prey includes:
- insects
- aquatic insects
- crustaceans
- worms
- snails
- other small invertebrates
It will also occasionally eat tiny fish and fish eggs. The least yellowlegs forages day and night on mudflats and shorelines, moving quickly on its long legs while feeding.
Breeding
The least yellowlegs breeds from mid May through July across northern North America. They nest on the ground in open boreal forests, often on dried mud or moss near water.
Both males and females are territorial during breeding and will defend nesting areas. However, they are socially monogamous each season and cooperate to raise young.
The nest consists of a shallow scrape lined with grasses, leaves, lichens, or other vegetation. The female lays 3-4 buff-colored eggs with brown splotches. Both parents incubate the eggs for 21-22 days until hatching. The precocial downy chicks leave the nest within a day and are able to feed themselves. The parents will brood them and actively defend them for the next few weeks as they grow.
The chicks fledge around 18-20 days after hatching. They reach sexual maturity and begin breeding after their first year. Least yellowlegs have been known to live up to 5-8 years in the wild.
Conservation Status
With a large population estimated at 350,000 birds, the least yellowlegs is listed as a species of Least Concern by the IUCN Red List. Their numbers increased during the early 20th century as new wetlands were created across North America by humans.
The least yellowlegs faces threats from habitat loss due to development and pollution. They are vulnerable to disturbances in their sensitive coastal wetland habitats. However, their ability to use diverse wetland types across a wide range gives them some resilience.
Where to Spot Least Yellowlegs
Here are some top places in North America to spot the least yellowlegs throughout the year:
Breeding Grounds
- Northern boreal forests in Canada and Alaska – find them along forest wetlands and ponds
- Coastal tundra wetlands in western Alaska
Migration Stopovers
- Interior U.S. wetlands – look for them at lakes, rivers, flooded fields
- Great Salt Lake, Utah
- Cheyenne Bottoms Wildlife Area, Kansas
- Sacramento River Delta, California
- Central Platte River, Nebraska
Wintering Grounds
- Coastal Texas
- Florida Gulf Coast
- Coastal Georgia
- Baja California, Mexico
- Yucatan Peninsula, Mexico
- Northern coasts of South America
The least yellowlegs can turn up at almost any marsh, wet meadow, mudflat, or lakeshore in migration as they move between their nesting and wintering grounds. Slowly walking wetland edges while scanning for small shorebirds is the best way to eventually spot one. Their constant tail bobbing often catches the eye once you’re close enough.
Conclusion
The least yellowlegs is a fairly small and delicate shorebird best identified by its thin bill, bright yellow legs, and petite appearance compared to the greater yellowlegs. Birders can spot these sociable shorebirds migrating and wintering along inland and coastal wetlands across North America. Their non-breeding range spans from Alaska to South America along the Pacific, Atlantic, and Gulf Coasts. Though they face some conservation threats, healthy populations of the least yellowlegs persist with as many as 350,000 individuals.