Red Knot (Calidris canutus rufa) numbers could be on the rise

Red Knot by Jan van de Kam

The North American subspecies of Red Knot (Calidris canutus rufa) is in trouble. Although Red Knot is globally a widespread species, this particular subspecies has declined dramatically because of past hunting activities and more recently competition for food in Delaware Bay.

Each year Red Knots stop over at Delaware Bay to feed on Horseshoe Crab eggs, but these birds competed directly for this food source with crab harvesters. This stop-off area is a critical point in their migration from South America to the Arctic where they breed. Birds arrive at Delaware Bay with almost no food reserves and after a few weeks of almost continuous feeding their fat levels are replenished and they’re ready to complete the final leg of the migration. Without sufficient reserves a lot of these departing birds perish en route to their breeding grounds.

Wiki provides a good overview of the various Red Knot subspecies, of which there are six.

Red Knot migration by ShyamalReports from researchers this year indicate that this subspecies may have turned the corner; their numbers appear to be on the rise. Here’s more from Philly.com:

Once numbering nearly 100,000 on the bay, the birds have declined to about 15,000. Biologists blame a reduction in the number of crabs, which were heavily harvested through the 1990s. Gradually, in what officials said was the first time a species not in trouble was regulated to help another that was, crab harvest restrictions have been enacted. Still, neither the crabs nor the birds have shown a comeback. Biologists fear the red knots could plummet into extinction with an event as simple as a summer snowstorm in the Arctic or an oil spill in South America. Advocates have repeatedly, but unsuccessfully, tried to get the U.S. Fish and Wildlife Service to designate the bird – a subspecies called Calidris canutus rufa – as federally threatened or endangered. Yesterday, the researchers packed up and headed home after spending a month on the bay capturing red knots with sophisticated netting devices. They logged biologic data and banded the birds before setting them free. Australian shorebird expert Clive Minton, who has joined Niles on the bay since 1997, called it “an exciting year. We think we’re really seeing the beginning of a possible turn-round in the fortunes of the crabs and the shorebirds.” [more here]

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