John James Audubon begins exploring Galveston Bay on the Texas coast on April 24, 1837. The area of the bay is approximately 600 square miles and is a part of one of the largest estuaries in the United States. He notes a Pileated woodpecker tapping on the roof of a house. In no other state has Audubon seen so many Pileated woodpeckers. High up in the trees the Cedar waxwing is trilling and “very numerous.” In the open, grassy areas the Eastern meadowlark is “very abundant.” Gadwalls are “quite abundant on all the inland ponds and streams, as well as on the brackish pools and inlets of the islands and shores of Galveston Bay.” Many other kinds of ducks are also visible, such as the Mallard, Blue-winged teal, American widgeon, Northern Shoveller, and American Black Duck. Some are even nesting.
When Audubon sees the Red knots take out from Galveston Bay and the shores of the Texas coast, Audubon notices they head eastward across the Gulf of Mexico to reach their nesting grounds. It took many years after Audubon’s publication of Birds of America to determine that Red knots travel tens of thousands of miles between their nesting grounds in the Arctic and their wintering grounds in such places as Terra del Fuego in southern Chile. There are current records of Red knots flying for as long as seven days straight.
In the fall, Audubon watches “great numbers” of the birds along the southeast Atlantic coast. It is also during this time of year that the Red knots gather to form murmations. “They follow each other in their course with a celerity that seems almost incomprehensible, when the individuals are so near each other that one might suppose it impossible for them to turn and wheel without interfering with each other. At such times, their lower and upper parts are alternately seen, the flock exhibiting now a dusky appearance, and again gleaming like a meteor.” European starlings and Bobolinks are known to fly in such formations. The Passenger pigeon and Carolina parakeet also flew in this manner before the guns of farmers and hunters eliminated them from the sky.
Hunters also once shot relentlessly at Red knots. The bird when “young and fat, is always welcome to the palate of the connoisseur in dainties.” Hunting laws and other forms of protection have helped the Red knot avoid extinction, but now they face loss of habitat from coastal development and the decline in the number of eggs of the Horseshoe crab, one of the bird’s most important sources of food. Red knots rely on the eggs of Horseshoe crabs to complete their marathon migration routes. Meanwhile, the Horseshoe crab has become a valuable resource for the pharmaceutical industry. The Horseshoe crab’s blood contains copper and can be used to expose bacteria in vaccines, drugs, and medical devices.
When writing about the Red knot, Audubon is convinced there is just one species. “The dimensions of birds of this family, as well as of many others, are extremely variable.” Upon further examination of specimens that he is able to collect, he concludes, “it would be difficult to find two of them having exactly the same size and proportions. If I add to this the very remarkable changes of plumage exhibited by birds of this family before and after maturity, you will not think it strange that [Alexander] WILSON should have mistaken the young of the Knot for a separate species from the old bird in its spring dress. Indeed, I am obliged to tell you that I have been much puzzled, when, on picking up several of these birds from the same flock, I have found some having longer and thicker bills than others, with as strange a difference in the size of their eyes. These differences I have endeavoured [sic] to represent in my plate.”
Though not separate, there is currently one species of Red knot (Calidris canutus) with a number of subspecies, among which is Alexander Wilson’s rufa (C. c. rufa). Joanna Burger, a biologist at Rutgers University, speculates in the New York Times the species is in deep trouble: “I think that we need to think about the red knot as a species that is dying, and we really need emergency measures.” The rufa subspecies is regarded as endangered in the United States. Biologist Larry Niles warns also in the New York Times, “Rufa knots, especially long-distance red knots, could be lost. We can’t stop bad winds or cold water, but we can expand the population of horseshoe crabs, so birds arriving in most of these conditions find an abundance of horseshoe crab eggs.” Whether one species, two separate species, or a species with subspecies, all appear headed toward extinction and then experience drastic measures to save them from vanishing.