Semipalmated sandpiper

DISTRIBUTION AND HABITAT

The semipalmated sandpiper is a migrant visitor to New Jersey’s coastal beaches and bay shores. The Delaware Bay is considered to be their most important spring migratory stopover in the eastern United States. Semipalmated sandpipers, along with millions of other shorebirds, visit the Delaware Bay during migration to feed on millions of horseshoe crab eggs. In late May, the arrival of shorebirds coincides with peak breeding season for horseshoe crabs. As long-distance migrants, semipalmated sandpipers make no other stops from their wintering grounds in South America to their breeding grounds in the Arctic.

After their long journey north, the semipalmated sandpiper reaches its breeding grounds in Arctic & subarctic Canada and coastal Alaska. Here they breed on grassy, dry tundra usually near water. In August and September, post-breeding females depart about 5 days prior to males. Most of the breeding population stages for fall migration at the Bay of Fundy and then fly directly over the ocean making landfall only in northeast South America. During the non-breeding months, they prefer mudflats, sandy beaches, and the shores of lakes & ponds.

DIET

Considered to be selective, but opportunistic foragers, the semipalmated sandpiper probes the ground for small arthropods, amphipods, polychaetes and occasionally insects & spiders. Foraging is regulated by the tidal cycle, mostly as the water recedes at low tide.

LIFE CYCLE

In late May into June, male semipalmated sandpipers arrive on their breeding grounds first and immediately begin setting up territories. Within the first week of the females arriving, pair bonds are formed. Their courtship begins with the males making numerous depressions in the ground for the female to choose from. Often the pairs return to previous successful nest sites. Pairs are typically monogamous with a high rate of reunion over several years.

In June, semipalmated sandpipers lay a 4 egg clutch, laying 1 egg per day. The eggs are dull white or olive buff with brown markings. Both adults will incubate the nest equally over a 19-21 day period. After the eggs hatch, both adults stay with the brood for 1-2 days. Within hours of hatching, the chicks are out of the nest bowl and foraging for food on their own. The female then leaves by day 6 and the male continues to rear the chicks. The chicks are fledged between 15-17 days old and leave the area where they were born several weeks after both parents have left.
In mid-August, juveniles begin to arrive at the staging area. Most juveniles do not breed as yearlings and stay on their wintering grounds until they are ready to breed in their 2nd year.