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Threats to migration pathways
Of the six subspecies of red knot, one is now stable, four are in
decline, and the trend in the sixth population is unclear. These
declines can be attributed to the loss of important feeding areas
and food sources along its migration routes. Both
C. c. canutus
and
C. c. islandica
, for example, are highly dependent upon the
shellfish resources of the Wadden Sea along the East Atlantic
flyway. However, as a result of embanking tidal habitats, and
mechanical shellfish harvesting in parts of the Wadden Sea, both
populations have suffered significant declines.
Similar situations exist for other knot populations. In China and
Korea, for example, large-scale reclamation projects have already
destroyed over 50 per cent of the tidal flats in the Yellow Sea over
the last 30 years with much more underway, putting enormous
pressure on both the
C. c. piersmai
and
C. c. rogersi
populations that
are unique to the East Asian-Australasian Flyway. Along the West
Atlantic flyway, overharvesting of horseshoe crabs in Delaware
Bay has resulted in a shortage of crab eggs for
C. c. rufa
and other
shorebirds. Their population has plummeted from over 100,000
birds in 2001 to fewer than 20,000 by 2011.
The red knot is a migratory shorebird that travels up to 20,000 km twice a year from its breeding grounds on
the high Arctic tundra to its southern non-breeding sites. Along with having one of the longest total migrations
of any bird, some populations also fly as much as 8,000–9,000 km between stopover sites in a single flight. As
a shellfish-eating specialist avoiding pathogen-rich freshwater habitats, the red knot relies on the few large tidal
flats with abundant food resources that the world has to offer. To undertake the physiologically demanding flight
from West Africa to northern Siberia, for example,
Calidris c. canutus
refuels during three weeks of fast feeding
in the national parks of Banc d’Arguin in Mauritania and the European Wadden Sea. After nearly doubling its
weight, it burns off stored fat during the 3 or more days of non-stop flying.
Red knot
(
Calidris canutus
)
CMS STATUS
CMS INSTRUMENT(S)
Appendix I & II
African-Eurasian Waterbird Agreement (AEWA)