Birds
Spotted Sandpiper
Actitis macularius · also called spotted sandpipers, teeter-tail
A spotted sandpiper teeters along a stream bank, its rear end bobbing almost constantly as it forages, while nearby a male of the species sits quietly on a nest the female who mated with him has already left behind to pursue another male elsewhere along the shore.
Overview
The spotted sandpiper, Actitis macularius, is a small, constantly bobbing shorebird that breeds along streams, rivers, ponds, and lakes across most of North America. Its genuinely reversed breeding roles, distinctive teetering walk, and status as one of the continent’s most widespread breeding shorebirds make it one of the more behaviourally remarkable birds found along North American waterways.
A shorebird that flipped the script
While most birds follow a pattern of male competition and female parental care, the spotted sandpiper does the opposite, with females competing for mates and males left holding nearly all the responsibility for incubating eggs and raising chicks.
Status
Least Concern, though populations have declined somewhat in parts of the range due to wetland habitat loss and degradation.
Spotted Sandpiper: common questions
Why does the female spotted sandpiper compete for mates instead of the male?
This species displays a genuine reversal of the breeding roles typical of most birds, with females arriving on the breeding grounds first to establish and defend territories, sometimes mating with multiple males in a single season, while each male takes on most or all of the incubation and chick-rearing responsibilities for the eggs left in his care.
Why does the spotted sandpiper bob its rear end while walking?
This species almost continuously teeters and bobs its rear end up and down while walking along shorelines, a distinctive and near-constant habit that gave rise to its nickname, teeter-tail, though the precise function of the behaviour is not fully settled among researchers.
How can you identify a spotted sandpiper in flight?
Look for a distinctive stiff-winged, shallow, fluttering flight style held low over the water, quite different from the flight of many other shorebirds, a pattern reliable enough to help confirm identification even when the bird's spotted breeding plumage cannot be seen clearly.
Where does the spotted sandpiper breed?
This species breeds along streams, rivers, ponds, and lakes across a very broad range of North America extending from the Arctic south to the central United States, making it one of the most widely distributed breeding shorebirds on the continent.