27-3-2017 VILLA LAPAS, COSTA RICA - SPOTTED SANDPIPER (Actitis macularius)

The Spotted Sandpiper, Actitis macularius, is a small and sprightly shorebird, easily recognized by its brown upperparts and white underparts adorned with distinctive black spots during the breeding season. These spots, which can indicate the bird's health, are most pronounced in females and tend to diminish in size and become more irregular with age. The species exhibits a white supercilium and has short yellowish legs paired with an orange bill that features a dark tip.

Adult Spotted Sandpipers can be identified by their unique plumage and behavior. Look for the all-brown back and tail, lacking the black found in many other sandpipers, and the white edges along the wings. In flight, their wing pattern appears somewhat washed out compared to their Eurasian counterpart, the Common Sandpiper. Their legs are typically light yellow, and they exhibit a characteristic bobbing walk, with their tails rhythmically moving up and down.

The Spotted Sandpiper, Actitis macularius, is a small and sprightly shorebird, easily recognized by its brown upperparts and white underparts adorned with distinctive black spots during the breeding season. These spots, which can indicate the bird's health, are most pronounced in females and tend to diminish in size and become more irregular with age. The species exhibits a white supercilium and has short yellowish legs paired with an orange bill that features a dark tip.

Adult Spotted Sandpipers can be identified by their unique plumage and behavior. Look for the all-brown back and tail, lacking the black found in many other sandpipers, and the white edges along the wings. In flight, their wing pattern appears somewhat washed out compared to their Eurasian counterpart, the Common Sandpiper. Their legs are typically light yellow, and they exhibit a characteristic bobbing walk, with their tails rhythmically moving up and down.

These birds favor breeding habitats near freshwater across North America, often selecting sites with some vegetative cover. They are not social birds and are rarely seen in flocks.

Spotted Sandpipers breed throughout most of Canada and the United States. They are migratory, wintering in the southern United States, the Caribbean, and South America. They are also rare vagrants to western Europe.

The Spotted Sandpiper is known for its polyandrous breeding system, where females may mate with multiple males and leave the incubation to them. Males dutifully care for the eggs and chicks, with incubation lasting about 20-23 days. The species is also known for its distinctive stiff-winged flight just above the water's surface.

The Spotted Sandpiper's vocalizations include a series of sharp, whistled notes. Their calls are often heard during flight or when the birds are agitated.

Females typically establish territories before males and may use successful breeding sites repeatedly. Males may father chicks from multiple clutches due to sperm storage within the female reproductive tract. Testosterone levels are notably higher in males during the pre-incubation period and in mated females compared to unmated ones.

These sandpipers forage on the ground or in shallow water, visually picking up food items such as insects, crustaceans, other invertebrates, small fish, and occasionally carrion. They are also known to catch insects mid-flight.

Eggs and chicks of the Spotted Sandpiper are preyed upon by raptors, mustelids, mice, and gulls.