Solitary Sandpipers are aptly named, as they are typically observed alone or in very small groups, particularly during migration through Oregon's freshwater wetlands, muddy margins of ponds, and even temporary puddles. They are distinct among sandpipers for their preference for these often more secluded habitats and their habit of bobbing the front half of their body.

When it comes to differentiating males and females, Solitary Sandpipers exhibit extremely subtle to no sexual dimorphism in their plumage. This means that, based on visual appearance alone in the field, it is virtually impossible to reliably determine the sex of an individual.

General Appearance of Adult Solitary Sandpipers (both sexes):
Size and Shape: A medium-small, slender shorebird, somewhat smaller than a Lesser Yellowlegs. They have a relatively long neck, long greenish legs, and a medium-length, straight, thin bill that is often dusky with a paler greenish or yellowish base.
Coloration:
Upperparts: Dark olive-brown (or grayish-brown, depending on subspecies and wear) finely spotted with whitish or buffy dots. These spots can be more prominent in breeding plumage.
Underparts: Crisp white belly.
Breast and Neck: The neck and upper breast are streaked with dusky gray, which can vary in density.
Eye-ring: A prominent white eye-ring is a key field mark. They also have a dark lore (area between the eye and bill) and a subtle pale supercilium (eyebrow stripe).
Tail: Distinctive in flight – a dark center (central tail feathers) contrasting with white outer tail feathers that are barred with black. This is a very useful identification feature.
Underwings: Dark underwings that contrast sharply with the white belly during flight. This is unique among North American shorebirds.
Behavioral Habits: Known for their characteristic head-bobbing or tail-trembling when foraging or agitated. When flushed, they often "tower" directly upwards before flying away, an adaptation likely for escaping from wooded or brushy environments.

While not reliable for field identification, some very subtle average differences have been noted in scientific studies:

1. Size: Females tend to be slightly larger and heavier on average than males, and may have **slightly longer bills and wing lengths**. However, this overlap in measurements between individuals of different sexes is extensive, making it impossible to determine sex from size alone for a single bird in the field.
2. Plumage: There are no consistent or discernible differences in plumage coloration, pattern, or intensity between males and females. Both sexes share the same cryptic olive-brown and white coloration.

Vocalizations:
Both sexes produce similar high-pitched, sharp, often rapid "peet-weet" or "kik-kik-kik" calls, especially when flushed. There are no commonly cited vocal differences that allow for sex determination.

Breeding Behavior (Not observed in Oregon, as they are migrants here):

It's worth noting that Solitary Sandpipers have unique breeding biology. Unlike most shorebirds that nest on the ground, they lay their eggs in old, abandoned songbird nests (such as those of American Robins or Rusty Blackbirds) in trees. Both parents share incubation duties. Males are territorial on their breeding grounds, performing exaggerated postures and aerial displays to defend their space, but these behaviors are typically observed in their northern breeding ranges (e.g., boreal forests of Canada and Alaska), not during their migration through Oregon.