LESSER YELLOWLEGS (Tringa flavipes) – (See images below)
DESCRIPTION: The Lesser yellowlegs has bright yellow long and slender legs and a black bill about the same length as the head, which helps to differentiate it from the Greater yellowlegs (see Similar Species below). The top parts are mottled brown, and the under parts are white, except the breast and neck which are white with brown streaks. Sexes are similar. The bird is around 24 cm (9 in.) long including the legs. It is a shorebird in the Sandpiper family.
VOICE: https://www.xeno-canto.org/species/Tringa-flavipes
NAME: The English name ‘Lesser’ implies that there is a ‘Greater’ species (which there is). The Latin genus name ‘tringa’ refers to a bird with a white rump and a bobbing tail in ancient Greece. (This movement can be seen in the video below.) As for the Latin species name ‘flavipes’, it means ‘yellow foot’.
HABITAT: In their breeding range, lesser yellowlegs inhabit open woodlands such as logged clearings or recently burnt areas. During migration and on their wintering grounds, they are found along the coasts and in wetlands such as marshes.
DIET: The lesser yellowlegs feeds on insects for the most part during breeding season. The rest of the year it will add other invertebrates such as crustaceans, and also some fish.
NESTING: This species builds its nest on the ground in well-hidden areas in small colonies. Usually four eggs of varying colors are laid, incubated by both parents. The chicks are independent from birth.
DISTRIBUTION: The lesser yellowlegs breeds in the northwest boreal forests of Canada and in Alaska. This bird’s wintering range includes Mexico and southward to South America. It is also a regular winter visitor on Hawaii.
DISTRIBUTION MAP: https://en.wikipedia.org/wiki/Lesser_yellowlegs#/media/File:Tringa_flavipes_map.svg
ON PEI: The lesser yellowlegs is common on Prince Edward Island in summer and fall during its migration. It is not known to breed on the island.
CONSERVATION: The population of the lesser yellowlegs has declined over the last few decades, which indicates that it needs some form of protection. In spite of this trend, it is still not considered at risk.
SIMILAR SPECIES: Greater Yellowlegs – It is not easy to tell the lesser yellowlegs apart from the greater yellowlegs. One way to distinguish them is by the bill length, which is longer than the head for the greater yellowlegs. Another way is by the species calls, which are different (see here for the greater yellowlegs calls). You can also check this reference: https://www.thespruce.com/greater-or-lesser-yellowlegs-386349 .
REFERENCES: http://www.seattleaudubon.org/birdweb/bird/lesser_yellowlegs

Lesser yellowlegs, Victoria Park, PEI, Canada, Aug. 2017 - © Denise Motard
Lesser yellowlegs, PEI, Canada, Aug. 2017

In this video below the lesser yellowlegs bobs its tail and also its head: