This past spring, I had the opportunity to spend a morning laying face down in the sand photographing red knots. This was a long time coming for me. For many years I have threatened to make a run up to Delaware Bay to photograph the great annual migration of the species. But thus far, my threats have been empty. Life, work, and an already overwhelming travel schedule that time of year has always kept me from doing so. This year, however, they came to me.
While in Florida this past April I walked out to the beach one morning thinking I would find a large flock of black skimmers and various species of terns, but instead was met with a tremendous flock of red knots. These birds are not only the largest of what birders call “peeps” (shorebirds), but one of the furthest traveled of any bird. Nesting in the high arctic of North America, each year these birds travel south to Terra del Fuego. Their round trip migration in a single year comes in at around 9,300 miles (15,000 Km).
This is an extraordinary feat for such a small bird. Consider the storms, the winds, the predators, the shotguns all along their way (yes, people shoot these birds for pleasure and for food down south). Imagine the caloric needs to do something like this – all within the span of a month or so. But minus the shotguns, these are threats that the little red knot has faced head on for a very long time.
In today’s world, things are a bit more complex than the last 13,000 years or so. The ice age is in the past. Today, we are in the age of humans. The Anthropocene if you will. And the age of the sixth great extinctions on this planet.
So let’s take the shotguns out of the equation. Let’s forget the fact that these birds were slaughtered by the tens of thousands each year for sport in the US, that their feathers were in high demand for women’s hats, and little has changed regarding all of this once you get south of the border. No. Instead, let’s focus on horseshoe crabs.
The horseshoe crab is one of the oldest unchanged species on the planet. For 445 million years these relatives of spiders have eked out a living along the shores of the world. To put this into perspective, these guys were around about 5 millions years before the first terrestrial life, in the form of fungus, existed.
Being horseshoe crabs, these guys don’t exactly spend any energy is raising young. In fact, very few species do. Instead, they live by the numbers game. Deposit millions of eggs, and hope for the best. And so each year, for 445 million years, these guys have been doing just that. Over time, as life continued to evolve, this ancient event became dependable. Predators learned that eggs meant calories. And for many, many, many millions of years various species have come to depend upon the annual horseshoe egg laying even each spring – including the red knot.
Migrating birds more or less hopscotch their way to wherever they are going. The exact locations of layovers are well planned and perfectly timed – the result of hard learned knowledge by the species over thousands of years. One of the most important layovers for the red knot happens to be Delaware Bay, timed perfectly to take advantage of the horseshoe crab egg laying. For many of these red knots, Delaware Bay is the last key stop before Canada and the high arctic. And for this last big push to their breeding grounds, they stop in to gorge themselves and nearly triple their weight on horseshoe crab eggs.
What this means then, is that their is a theoretical weak link in the migration of these birds: food. Only the in the Anthropocene can we call a predictable 445 million year old food source a weak link though. But here we are in the 21st century, a time when horseshoe crabs have become a commodity, a fishery, and like all other species in the world, once a dollar can be made off them, their numbers quickly dwindle. In this case, its all for eel bait.
The result? Since the 1980s, 50% fewer red knots have made it back from their wintering grounds each year. 50%! Imagine for a moment if we changed the elements of this statement. What if we said that since the 1980s, the human population has collapsed by 50%? What then? Now, some of you may cheer over this of course. But I am sure you get my meaning here. And so, since 2014, the diminutive little red knot, that most beautiful of all our shorebirds, was placed on the “threatened” list of species in the US. All because of eel bait.