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The Red Knots call

Bill Meredith

He must go — go — go away from here!
On the other side the world he's overdue.
'Send your road is clear before you when the old Spring-fret comes o'er you,
And the Red Gods call for you!
… Rudyard Kipling, 1897: "The Feet of the Young Men"

(6/2016) When I was in graduate school learning to be an ecologist, one of the scientists who influenced me was Paul Errington. He was a professor at Iowa State University, where he studied the ecology of muskrats; his research helped develop our understanding of how animal populations are controlled by predators. I read some of his research papers, but the thing that really impressed me was his autobiography, The Red Gods Call. He wrote beautifully, and told of growing up on a farm in Iowa and being a Boy Scout. In those days, many of the activities of Boy Scouts dealt with survival and were patterned on Indian lore, and Kipling’s poem was widely quoted in Scout literature. Errington took it to heart. He wanted to go to college and study biology, but he couldn’t afford it; so he decided to go to Canada and spend a winter fur-trapping. He lived alone through the Canadian winter in an abandoned log cabin, setting trap lines every day and cleaning and preparing the pelts, in addition to the daily chore of cutting firewood. He caught beaver, foxes, muskrats, weasels, skunks, and an occasional mink, and he survived by eating whatever he caught, including the skunks.

From the beginning, the thing that intrigued me about Ecology was the way everything in nature turns out to be connected when you begin to study it in detail. I never got to meet Dr. Errington in person, and my own studies had nothing to do with muskrats; but reading his book showed me the persistence and determination that are required for success, and how important the experiences in adolescence can be. And in the last two months, memories based on the title of his book have morphed from the original version in Kipling’s poem to my own version. Instead of Red Gods, I heard the Red Knots calling, and their calls converged with an opportunity to enjoy practicing ecology again for a few days.

It started a couple of months ago when I received a notice that the Audubon Society would meet at Cape May, New Jersey, for their annual outing to observe the migration of Red Knots. The Red Knot is a type of sandpiper; I first heard about it in some of my earliest Ecology courses. I looked for Knots at every field trip and vacation that I took to a beach for the next 40 years, but I never saw one until September 7, 1999, when I was vacationing in North Carolina with my grandchildren. I was not impressed. Knots normally travel in flocks by the thousands, but there before me was a single scrawny individual, already in its drab winter plumage. But, it counted as another species for my life list, so I dutifully recorded the date and location in my bird book. A year of two later my wife and I drove to Cape May in hopes of seeing the migration, but we were too early by a week; the Knots had not arrived. And then, as years of retirement slipped by, the time arrived when I no longer felt comfortable driving long distances to unfamiliar places in heavy traffic. Then, out of the blue, my son offered to take me to Cape May as a birthday present.

As Lewis Carroll would have said, it was a frabjous three days. It was windy and rainy, but no matter; the Knots were there by the thousands, and they were hungry. They were crowded together so densely that if you were more than 50 feet away you could not make out individual birds. Crowds of them would run to the water’s edge as the waves broke in and out, gobbling up horseshoe crab eggs as they ran. It looked as if the whole beach was moving. Of course, there were other kinds of birds to look at… I listed 55 species of them, and probably would have got 25 more if I could see and hear better… but the Knots were the stars of the show.

Red Knots begin their annual trip in southern Argentina, and migrate to the tundra region of northern Canada, one of the longest annual migrations known. Each spring, the whole population of Knots leaves Argentina in late February, and they fly some 2,000 miles, non-stop, across Brazil. They stop along the beaches of northern Brazil for a few days to eat, and then they fly across the Caribbean to Florida, where they stop again to "re-fuel." Then it is on to Cape May, where they make the most important stop of the entire trip. By the time they arrive here, they have nearly exhausted the fat reserve in their bodies; they have lost over half of their body weight, and are literally "out of gas." They need a rich, plentiful food supply, and they find it in the eggs of horseshoe crabs, which spawn on the sandy beaches of Delaware Bay at the time of the high tides in May. So the whole population of Red Knots descends on Cape May, and they stay there two or three weeks, gorging themselves on horseshoe crab eggs until they have doubled their body weight, under the watchful eyes of hundreds of enthusiastic birders, both amateur and professional. And then, it is on to the Tundra north of Hudson’s Bay, where they will nest and raise their young.

In the 1800s observers wrote that flocks of migrating Red Knots darkened the skies as they flew northward. There was no way in those days to determine accurately how many there were, but estimates ranged in the millions. Market hunters shot thousands of them, and by 1890 it appeared that they might become extinct, as the Passenger Pigeons had. Market hunting was banned along most of the U. S. coast, and the population began to recover; but in the 1920s, that peculiar ecological connection between different species occurred. It was discovered that horseshoe crabs make excellent fertilizer when dried and ground up. People began harvesting the crabs in nets by the ton; the crab population crashed, and the Red Knots found their food supply dropping rapidly. Crab fishing for fertilizer was stopped, and both crab and Knot populations began to recover. Then, in the 1970s it was discovered that the blood of horseshoe crabs contains the most effective agent known for sterilizing surgical equipment and for testing how many bacteria survive after being treated with new antibiotics or sterilizing agents, so the crab population crashed again… and, predictably, the Knot population followed. In 1995, restrictions were imposed on crab harvesting, and the decline slowed but did not recover. The Red Knot population was estimated to be about 150,000 then; it continues to drop for a few years, but recently has increased slightly. The accuracy of estimating population numbers has improved in recent years by scanning aerial photographs with computers; last year’s estimate was 18,000 birds. On May 22 this year, 9,000 Knots were counted in one day on the beaches around Delaware Bay where I was.

The demand for serum made from horseshoe crab blood continues to grow; on the current market, a gallon of crab blood treated for medical use sells for as much as $60,000. Speakers at the Audubon meeting said the crab population seems to be stabilizing at the present; but the crabs spend most of their lives in the ocean, which is becoming more polluted as coastal developers continue to build. Maybe I should not be concerned; I am old, and I have seen the Red Knots. But still, as I doze in my recliner, I can hear the Red Gods calling.

Read other articles by Bill Meredith