As a follow-up to last night's post, this year's banding sessions have found that red knots are not gaining as much weight as usual. I suspect that part of the problem was that a large storm swept through the bay right as horseshoe crabs started spawning. However, a strong weather event would not have such an impact in the situation were not already dire.
Biologists have determined that the knots need a density of about 50,000 pearlescent crab eggs per square meter of beach to feed efficiently.Next winter's surveys in South America will tell what effects this will have on the red knot population. I fear that this will bring the bird closer to the extinction – and very soon.
But this year, a May storm swept the eggs from the beaches. Afterward, the crab spawn, exquisitely timed to the arrival of the birds, slowed.
Counts showed an average density of fewer than 500 eggs per square meter.
In 1997, about 80 percent of the birds leaving the bay had bulked up to a needed weight of about 180 grams, or six ounces.
This year, based on data obtained from birds that were captured in nets, only 15 percent - the lowest proportion biologists have yet seen - gained sufficient weight.