Breeding adult. Photo: Brian Kushner/Flickr
Calidris canutus
| Conservation status | Once far more numerous in North America, but huge numbers were shot on migration in late 1800s. Some populations have declined sharply since the 1960s. The subspecies that migrates from southern Argentina to the Canadian Arctic in spring relies on stopover habitat along Delaware Bay, where the knots fatten up on the superabundant eggs of horseshoe crabs before they continue north to the Arctic. Overharvesting of horseshoe crabs along the central Atlantic Coast has led to a sharp reduction in this food source for migratory shorebirds, and Red Knots seem to have been hit hard by this. |
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| Family | Sandpipers |
| Habitat | Tidal flats, shores; tundra (summer). In migration and winter on coastal mudflats and tidal zones, sometimes on open sandy beaches of the sort favored by Sanderlings. Nests on Arctic tundra, usually on rather high and barren areas inland from coast, but typically near a pond or stream. |
On tidal flats, forages mostly by probing in mud with bill, finding food by touch. On dry sand and on tundra breeding grounds, forages mostly by sight, picking items from surface.
3-4. Pale olive-green, with small brown spots. Incubation is by both sexes (although male may do more), 21-22 days. Young: Downy young leave nest soon after hatching. Both parents tend young at first, but female leaves before young are old enough to fly. Young feed themselves. Young are able to fly at about 18-20 days after hatching, become independent about that time.
Downy young leave nest soon after hatching. Both parents tend young at first, but female leaves before young are old enough to fly. Young feed themselves. Young are able to fly at about 18-20 days after hatching, become independent about that time.
Includes mollusks, insects, green vegetation, seeds. In migration and winter, feeds on small invertebrates that live in mud of intertidal zone, especially small mollusks, also marine worms, crustaceans. On breeding grounds, feeds mostly on insects, especially flies. Also eats much plant material, especially early in breeding season (when insects may be scarce), including shoots, buds, leaves, and seeds.
Early in breeding season, male flies in high circles above territory, hovering on rapidly quivered wings and then gliding, while giving mellow whistled calls. Female may fly around territory with male. On ground, male displays with wings held high. Nest site is on ground on open tundra, usually near water. Nest is a shallow scrape lined with leaves, lichen, moss.
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.
In the final days of 2020, Congress boosted funding for the crucial Delaware River Basin Restoration Program and critical regional conservation efforts.
Vaccine production requires the blood of horseshoe crabs, whose eggs are a vital food source for several species, including Red Knots. A synthetic replacement for the blood exists, but the United States is stuck in the past.
U.S. Fish and Wildlife Service program supports bird conservation in three critical regions of the watershed.
Protecting freshwater in Delaware, New Jersey, New York, and Pennsylvania for birds and people.
Protecting shorebirds in habitats especially vulnerable to development and climate threats
Protecting the Central Flyway’s diverse marsh and wetland habitats for migrating species
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