New Study Finds Humboldt Bay is Among the Most Important Places in the Entire Hemisphere for Migratory Shorebirds
Its intertidal mudflats crowded with migratory shorebirds each year, this California bay is threatened by the aquaculture industry.
Breeding adult. Photo: Kyle Dudgeon/Audubon Photography Awards
Calidris alpina
Conservation status | Numbers wintering in some coastal areas have declined noticeably since the 1970s; the reasons for this are unknown. |
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Family | Sandpipers |
Habitat | Tidal flats, beaches, muddy pools; wet tundra in summer. During migration and winter, widespread in coastal habitats; mainly mudflats, but also sand beaches, rocky shores. Inland, occurs on lake shores, sewage ponds, flooded fields. Breeds on wet tundra, especially areas with hummocks, tussocks, and low ridges interspersed with ponds and marshy spots. |
Forages by picking at items on surface or by probing in mud, sometimes with very rapid "stitching" motion, probing several times per second. May feed by day or night.
4, sometimes 2-3, perhaps very rarely more than 4. Olive or blue-green to buff, with brown blotches concentrated at larger end. Incubation is by both sexes (mostly female during night, male during day), 20-24 days. Young: Downy young leave nest soon after hatching. Both parents tend young at first, but female often departs after a few days. Young feed themselves, are able to fly at age of 19-21 days.
Downy young leave nest soon after hatching. Both parents tend young at first, but female often departs after a few days. Young feed themselves, are able to fly at age of 19-21 days.
Mostly insects on tundra, other small invertebrates on coast. Diet varies with season and location. On breeding grounds feeds heavily on insects, including midges, crane flies, beetles, and others. On coast eats wide variety of small creatures found in intertidal zone, including marine worms, snails and other mollusks, amphipods and other crustaceans, sometimes small fish. Sometimes eats seeds and leaves.
In display flight, male circles slowly over breeding territory, fluttering and gliding, while singing. On ground, reacts to intruding males by advancing, pausing to raise one wing high over back. Courtship may involve ritualized nest-making movements. Nest site is on ground, usually well hidden in or under grass clump or in hummock. Nest is a shallow scrape, lined with leaves and grass. Both sexes make scrapes, but female chooses one and completes nest.
Audubon’s scientists have used 140 million bird observations and sophisticated climate models to project how climate change will affect this bird’s range in the future.
Zoom in to see how this species’s current range will shift, expand, and contract under increased global temperatures.
Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.
Its intertidal mudflats crowded with migratory shorebirds each year, this California bay is threatened by the aquaculture industry.
Audubon supports the Shovel-Ready Restoration Grants for Coastlines and Fisheries Act of 2020.
Since the DDT ban, the raptor's populations have boomed—spurring their shorebird prey to adjust in several ways.
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