Bird of the Month: Spotted Sandpiper
By Andy McCormick
PC: Mick Thompson (Spotted Sandpiper)
Scientific Name: Actitis macularia
Length 7.5 in
Wingspan 15 in
Weight 1.4 oz (40 g)
AOU Band code SPSA
The Spotted Sandpiper is probably the most widespread breeding sandpiper in North America, but it is one of a very small minority of sandpipers with one of the least common gender roles. Females arrive on the breeding ground first and will display to attract the males as they arrive. They also can practice serial polyandry in that once paired with one male, which is most often left to brood the eggs, the female courts up to three additional males for breeding in new nests. At times females will assist with brooding and feeding the young. Blood tests have revealed that during nesting the male Spotted Sandpiper has higher levels of prolactin, a hormone that encourages caretaking behavior. Females are larger and more aggressive than the males.
The Spotted shares the genus Actitis, Greek aktitis, a shore dweller, with the Common Sandpiper ( A. hypoleucos) its Eurasian cousin, and its species name is from the Latin maculo, a spot, referencing its breeding plumage (Holloway).
The Spotted is primarily a fresh water shorebird with generalist habits making it very adaptable to a wide variety of aquatic environments including the banks of rivers, ponds, lakes, and agricultural and urban wetlands (Oring, et al). It nests near water in a shallow depression lined with moss and grass. A clutch of usually four buff-colored eggs with brown splotches is incubated primarily by the male. The young hatch in about three weeks with first flight following in another two and a half weeks. The young feed themselves attended by the male (Kaufman).
Breeding occurs from the northern half of the United States north to the tree line with birds arriving in Washington around the middle of May. Fall migration begins with the first adults departing in July. However, the Puget Sound and Pacific coastal regions are wintering areas for Spotted Sandpipers and they can be seen year-round in our area. Both adults have breast spots in their alternative or breeding plumage, but are pure white breasted in basic plumage in winter. Clear-breasted birds in the late summer and early fall in the Northwest are likely to be juveniles (Paulson). Later in the winter all Spotteds will have a clear breast. Some Spotted Sandpipers migrate long distances to wintering grounds in Costa Rica and Panama and further south to Venezuela, Ecuador and Peru locating similar watery habitat. Others make a short hop from Canada to the Pacific coastal region.
When perched or foraging many Spotteds display an almost constant tail bobbing. Long-time birders might remember this species’ nicknames such as teeter-peep or teeter-snipe (Oring, et al). They also have a clever flight pattern and are usually seen flying very low over water or along the water’s edge with “rapidly fluttering wings held below the horizontal… No other Northwest shorebird flies like this (Paulson). This shallow wing-beat allows them to fly closer to the surface of water to pick off insects above or on the water.