Yellowlegs and sandpipers are two groups of migratory shorebirds that can often be seen together along beaches, mudflats, and wetlands across North America. While they occupy similar habitats and fill comparable ecological niches, there are several key differences between yellowlegs and sandpipers in terms of their appearance, behavior, breeding habits, and taxonomy.
What are Yellowlegs?
Yellowlegs are large shorebirds characterized by their bright yellow legs and long bills. There are two species of yellowlegs found in North America:
Greater Yellowlegs
The greater yellowlegs (Tringa melanoleuca) is the largest of the “yellowlegs” at around 14 inches in length. Their bills are long and slightly upturned. Their plumage is gray and white with streaking on the chest during breeding season. They have a loud, three-note whistle call.
Lesser Yellowlegs
The lesser yellowlegs (Tringa flavipes) is very similar to the greater yellowlegs but smaller in size at around 10-12 inches in length. Their bills are more slender and straight. Their plumage is gray and white but with more solid gray on the back and more white underneath. Their call is a series of faster, higher-pitched whistles.
What are Sandpipers?
Sandpipers are a diverse group of small to medium-sized shorebirds characterized by their upturned bill shape. There are over 20 species of sandpipers in North America, including:
Spotted Sandpiper
The spotted sandpiper (Actitis macularius) is a widespread species in North America, recognizable by its stiff teetering walk and the rows of spots on its white underparts during breeding season. It bobs its tail habitually.
Least Sandpiper
The smallest sandpiper species in North America at just 5-6 inches long. In breeding plumage they have bold brown streaking on the chest. Outside of breeding season they are plain gray above and white below.
Pectoral Sandpiper
A medium-sized sandpiper with yellow-green legs and a drooped bill tip. Breeding males have heavy streaking on the breast. They forage by probing vigorously in mud.
Semipalmated Sandpiper
A small sandpiper with partially webbed toes. Breeding birds have reddish feathers on the neck and black markings on the breast. They often forage in large flocks.
Western Sandpiper
The most abundant small sandpiper on the west coast of North America. They have black legs and a short, thin, dark bill. Breeding birds are brightly rusty colored on the head, breast, and back.
Differences in Appearance
While yellowlegs and sandpipers occupy similar habitats, there are some key physical differences between the two groups:
- Size: Yellowlegs are substantially larger than sandpipers. Yellowlegs range from 10-14 inches in length whereas sandpipers are generally 5-9 inches.
- Legs: As their name suggests, yellowlegs have bright yellow legs. Sandpipers have black, green, or orange legs.
- Bills: Yellowlegs have very long, slightly upturned bills. Sandpipers have shorter bills of variable shape.
- Plumage: Yellowlegs have fairly simple gray and white plumage. Sandpipers often have more complex patterning and can display rusty colors during breeding season.
These differences in appearance can help birders distinguish between yellowlegs and sandpipers when viewed from a distance. However, it’s always best to use multiple field marks when identifying shorebirds since some species can overlap in size and coloration.
Differences in Behavior
In addition to physical differences, yellowlegs and sandpipers have some general behavioral distinctions:
- Feeding: Yellowlegs wade and probe in deeper water. Sandpipers probe along the water’s edge and on wet mud.
- Flocking: Yellowlegs are often solitary or in pairs. Sandpipers frequently feed in large flocks, sometimes mixed with other shorebird species.
- Flight: Yellowlegs have slower, stiffer wingbeats. Sandpipers have quicker wingbeats and are more agile fliers.
- Vocalizations: Yellowlegs have loud, ringing whistle calls. Sandpipers have softer chattering calls.
Observing how the birds move and feed can provide helpful clues about their identity when combined with field marks. However, there is some overlap in behavior between the two groups. Juvenile yellowlegs sometimes feed in loose flocks, for example.
Differences in Breeding
Yellowlegs and sandpipers have some notable differences in their breeding biology:
- Habitat: Yellowlegs nest in open wetlands and bogs. Sandpipers nest in a wider variety of habitats including prairies, tundra, and coastal beaches.
- Nesting: Yellowlegs nest on the ground in shallow depressions. Many sandpipers nest right on exposed beaches.
- Eggs: Yellowlegs lay clutches of 4 eggs. Sandpipers lay anywhere from 2-5 eggs depending on species.
- Incubation: Yellowlegs eggs hatch in 22-24 days. Sandpiper eggs can hatch in as little as 17-21 days.
- Chicks: Yellowlegs chicks feed themselves. Sandpiper chicks are fed by their parents.
These breeding differences stem from the larger body size and slower life history of yellowlegs compared to the smaller, faster-developing sandpipers. The nesting habits of each group are adapted to their favored habitats.
Taxonomic Differences
Beyond physical attributes and behavior, yellowlegs and sandpipers are taxonomically distinct:
- Order: Both are members of the order Charadriiformes, which contains gulls, auks, plovers, and other shorebirds.
- Family: Yellowlegs belong to Scolopacidae, the typical shorebird family. Sandpipers belong to multiple families including Scolopacidae and Scolopacidae.
- Genus: The two yellowlegs species comprise the genus Tringa. Sandpipers comprise over a dozen genera including Calidris, Limnodromus, and Actitis.
This taxonomic separation indicates that yellowlegs and sandpipers have different evolutionary histories despite occupying similar ecological roles today. Their ancestral shorebird lineages adapted to specialized niches over time leading to the diversity seen among modern shorebirds.
Comparison Table
| Trait | Yellowlegs | Sandpipers |
|---|---|---|
| Size | 10-14 inches | 5-9 inches |
| Legs | Bright yellow | Black, green, orange |
| Bill shape | Long, slightly upturned | Short, variable shapes |
| Plumage | Simple gray & white | Often rusty colors |
| Feeding behavior | Wade and probe in deep water | Probe in shallows and mud |
| Flocking | Solitary or paired | Often in large flocks |
| Flight style | Slow, stiff wingbeats | Quick, agile wingbeats |
| Vocalizations | Loud whistles | Soft chatters |
| Nesting habitat | Open wetlands | Varied habitats |
| Clutch size | 4 eggs | 2-5 eggs |
| Incubation period | 22-24 days | 17-21 days |
Conclusion
In summary, yellowlegs and sandpipers overlap broadly in their ecology as migratory shorebirds but can be distinguished by careful observation of size, plumage, vocalizations, behavior, and preferred habitats. Yellowlegs tend to be larger, with simple gray and white patterns, whistling calls, deep water wading habits, solitary tendencies, and preferences for open wetland nesting. Sandpipers encompass diverse smaller species, often with rusty breeding plumage, soft chatter calls, shallow mud probing habits, flocking tendencies, and varied nesting habitats ranging from tundra to beaches. Understanding these key differences aids birders and biologists in identifying yellowlegs and sandpipers when they encounter them in the field.
