Spotted Sandpiper, Actitis macularius
The Spotted Sandpiper (Actitis macularius) is a shorebird of small size. It measures 18 to 20 centimeters long. In addition with its sister species, the Common Sandpiper, they make up the genus Actitis. They replace each other geographically; stray birds may settle with breeders of the other species and hybridize.
Their breeding habitat is close by fresh water across most of Canada and the United States. They migrate to the southern United States and South America, and are very rare vagrants to Western Europe. These are not gregarious birds and are not seen commonly in flocks.
The adult individuals have short yellowish colored legs and an orange bill with a dark tip. The body is brown on the top and white underneath with scattered black spots. The non-breeding birds lack the spotted underparts and are much like the Common Sandpiper of Eurasia; the main difference is the more washed-out wing pattern that is visible in flight and the usual light yellow legs and feet of the Spotted Sandpiper. The Actitis species have a distinctive flight low over the water with their wings stiff.
They nest on the ground. During each summer breeding season, the females may mate with and lay clutches for more than one male, leaving the incubation duties to them. This act is referred to as polyandry. The male parents of first clutches may father chicks in later males clutches, most likely because of sperm storage within female reproductive tracts, which is very common amongst birds. The females that fail to find additional mates usually help incubate and rear the chicks. Mated females have concentrations of testosterone that are seven times higher than those of unmated females.
These sandpipers forage on the ground or water, picking up food utilizing their sight. They may also catch insects while in flight. They consume crustaceans, other invertebrates and insects. As they forage for this food, they can be recognized by their constant nodding and teetering.
Image Caption: Spotted Sandpiper (Actitis macularia), Bluffer’s Park (Toronto, Canada). Credit: Mdf/Wikipedia (CC BY-SA 3.0)