WatchList Species Account for Red Knot (Calidris cantus) |
the list as a Declining Yellow List Species
Breeding also in two areas of Siberia,
the Red Knot’s North American population breeds in northwestern
and northern Alaska, the high arctic islands of Canada south
to islands in northern Hudson’s Bay, and on Greenland.
The birds breeding in Greenland and the Canadian arctic islands
winter in Europe, while the majority of the remaining birds
breeding in North America winter in southern South America,
with a few along both coasts of North America.
The total numbers of the bird are estimated
at three million, with the Alaskan breeders in the low hundreds
of thousands, but aerial surveys in recent years suggest that
numbers at the North American staging areas and South American
wintering areas have fallen drastically in the past 30 years,
with a drop in numbers as high as 50%.
Red Knots are among the longest-distant
migrants of any birds—those spending the non-breeding
season in Tierra del Fuego travel over 9,000 miles each way between
there and their breeding areas. The knot is also known for
gathering in large flocks at staging areas during migration
before making long-distance nonstop flights, some more than
1,500 miles, to the next traditional stopping area on their long
flight. The species is quite faithful to specific staging
areas along the migration route; one of the most important
of these in North America is the tidal mudflats along Delaware
Bay, where thousands gather in mid- to late May to feed on
the eggs of the horseshoe crab for a few days and accumulate
body fat needed for the long continuing journey to their arctic
breeding grounds. As many as 94,000 were estimated to be present
there during one census count, and estimates of up to 92%
of the entire population of the Alaska-breeding subspecies
were present on a single day.
This means the bird is very vulnerable
to ecological disaster and short food supplies at a single
site; a recent move to limit harvest of horseshoe crabs at
Delaware Bay will help conserve the bird. The bird is also
hunted in South America, particularly in the Guianas. All
areas used by the bird, whether for breeding, non-breeding,
or migration, are among those where the effects of global
climate change are expected to be the greatest.